1658 lines
58 KiB
XML
1658 lines
58 KiB
XML
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<?xml version="1.0"?>
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<ruleset name="Design"
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xmlns="http://pmd.sourceforge.net/ruleset/2.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://pmd.sourceforge.net/ruleset/2.0.0 https://pmd.sourceforge.io/ruleset_2_0_0.xsd">
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<description>
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Rules that help you discover design issues.
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</description>
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<rule name="AbstractClassWithoutAnyMethod"
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language="java"
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since="4.2"
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class="net.sourceforge.pmd.lang.rule.XPathRule"
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typeResolution="true"
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message="No abstract method which means that the keyword is most likely used to prevent instantiation. Use a private or protected constructor instead."
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externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#abstractclasswithoutanymethod">
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<description>
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If an abstract class does not provides any methods, it may be acting as a simple data container
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that is not meant to be instantiated. In this case, it is probably better to use a private or
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protected constructor in order to prevent instantiation than make the class misleadingly abstract.
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</description>
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<priority>1</priority>
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<properties>
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<property name="xpath">
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<value>
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<![CDATA[
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//ClassOrInterfaceDeclaration
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[@Abstract = 'true']
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[count(//MethodDeclaration) + count(//ConstructorDeclaration) = 0]
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[not(../Annotation/MarkerAnnotation/Name[pmd-java:typeIs('com.google.auto.value.AutoValue')])]
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]]>
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</value>
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</property>
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</properties>
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<example>
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<![CDATA[
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public abstract class Example {
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String field;
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int otherField;
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}
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]]>
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</example>
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</rule>
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<rule name="AvoidCatchingGenericException"
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since="4.2.6"
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language="java"
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message="Avoid catching generic exceptions such as NullPointerException, RuntimeException, Exception in try-catch block"
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class="net.sourceforge.pmd.lang.rule.XPathRule"
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externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#avoidcatchinggenericexception">
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<description>
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Avoid catching generic exceptions such as NullPointerException, RuntimeException, Exception in try-catch block
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</description>
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<priority>3</priority>
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<properties>
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<property name="xpath">
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<value>
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<![CDATA[
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//CatchStatement/FormalParameter/Type/ReferenceType/ClassOrInterfaceType[
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@Image='NullPointerException' or
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@Image='Exception' or
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@Image='RuntimeException']
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]]>
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</value>
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</property>
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</properties>
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<example>
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<![CDATA[
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package com.igate.primitive;
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public class PrimitiveType {
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public void downCastPrimitiveType() {
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try {
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System.out.println(" i [" + i + "]");
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} catch(Exception e) {
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e.printStackTrace();
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} catch(RuntimeException e) {
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e.printStackTrace();
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} catch(NullPointerException e) {
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e.printStackTrace();
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}
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}
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}
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]]>
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</example>
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</rule>
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<rule name="AvoidDeeplyNestedIfStmts"
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since="1.0"
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message="Deeply nested if..then statements are hard to read"
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class="net.sourceforge.pmd.lang.java.rule.design.AvoidDeeplyNestedIfStmtsRule"
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externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#avoiddeeplynestedifstmts">
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<description>
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Avoid creating deeply nested if-then statements since they are harder to read and error-prone to maintain.
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</description>
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<priority>3</priority>
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<example>
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<![CDATA[
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public class Foo {
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public void bar(int x, int y, int z) {
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if (x>y) {
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if (y>z) {
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if (z==x) {
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// !! too deep
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}
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}
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}
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}
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}
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]]>
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</example>
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</rule>
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<rule name="AvoidRethrowingException"
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language="java"
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since="3.8"
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message="A catch statement that catches an exception only to rethrow it should be avoided."
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class="net.sourceforge.pmd.lang.rule.XPathRule"
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externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#avoidrethrowingexception">
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<description>
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Catch blocks that merely rethrow a caught exception only add to code size and runtime complexity.
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</description>
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<priority>3</priority>
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<properties>
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<property name="xpath">
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<value>
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<![CDATA[
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//CatchStatement[FormalParameter
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/VariableDeclaratorId/@Image = Block/BlockStatement/Statement
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/ThrowStatement/Expression/PrimaryExpression[count(PrimarySuffix)=0]/PrimaryPrefix/Name/@Image
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and count(Block/BlockStatement/Statement) =1]
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]]>
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</value>
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</property>
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</properties>
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<example>
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<![CDATA[
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public void bar() {
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try {
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// do something
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} catch (SomeException se) {
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throw se;
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}
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}
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]]>
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</example>
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</rule>
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<rule name="AvoidThrowingNewInstanceOfSameException"
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since="4.2.5"
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language="java"
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message="A catch statement that catches an exception only to wrap it in a new instance of the same type of exception and throw it should be avoided"
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class="net.sourceforge.pmd.lang.rule.XPathRule"
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externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#avoidthrowingnewinstanceofsameexception">
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<description>
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Catch blocks that merely rethrow a caught exception wrapped inside a new instance of the same type only add to
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code size and runtime complexity.
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</description>
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<priority>3</priority>
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<properties>
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<property name="xpath">
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<value>
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<![CDATA[
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//CatchStatement[
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count(Block/BlockStatement/Statement) = 1
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and
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FormalParameter/Type/ReferenceType/ClassOrInterfaceType/@Image = Block/BlockStatement/Statement/ThrowStatement/Expression/PrimaryExpression/PrimaryPrefix/AllocationExpression/ClassOrInterfaceType/@Image
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and
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count(Block/BlockStatement/Statement/ThrowStatement/Expression/PrimaryExpression/PrimaryPrefix/AllocationExpression/Arguments/ArgumentList/Expression) = 1
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and
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FormalParameter/VariableDeclaratorId = Block/BlockStatement/Statement/ThrowStatement/Expression/PrimaryExpression/PrimaryPrefix/AllocationExpression/Arguments/ArgumentList/Expression/PrimaryExpression/PrimaryPrefix/Name
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]
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]]>
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</value>
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</property>
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</properties>
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<example>
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<![CDATA[
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public void bar() {
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try {
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// do something
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} catch (SomeException se) {
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// harmless comment
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throw new SomeException(se);
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}
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}
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]]>
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</example>
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</rule>
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<rule name="AvoidThrowingNullPointerException"
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language="java"
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since="1.8"
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message="Avoid throwing null pointer exceptions."
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class="net.sourceforge.pmd.lang.rule.XPathRule"
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externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#avoidthrowingnullpointerexception">
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<description>
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<![CDATA[
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Avoid throwing NullPointerExceptions manually. These are confusing because most people will assume that the
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virtual machine threw it. To avoid a method being called with a null parameter, you may consider
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using an IllegalArgumentException instead, making it clearly seen as a programmer-initiated exception.
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However, there are better ways to handle this:
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|||
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>*Effective Java, 3rd Edition, Item 72: Favor the use of standard exceptions*
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>
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|||
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>Arguably, every erroneous method invocation boils down to an illegal argument or state,
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but other exceptions are standardly used for certain kinds of illegal arguments and states.
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If a caller passes null in some parameter for which null values are prohibited, convention dictates that
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NullPointerException be thrown rather than IllegalArgumentException.
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To implement that, you are encouraged to use `java.util.Objects.requireNonNull()`
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(introduced in Java 1.7). This method is designed primarily for doing parameter
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validation in methods and constructors with multiple parameters.
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Your parameter validation could thus look like the following:
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```
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public class Foo {
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private String exampleValue;
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void setExampleValue(String exampleValue) {
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// check, throw and assignment in a single standard call
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this.exampleValue = Objects.requireNonNull(exampleValue, "exampleValue must not be null!");
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}
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}
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```
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]]>
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</description>
|
|||
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<priority>1</priority>
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<properties>
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|||
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<property name="xpath">
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<value>
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<![CDATA[
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//AllocationExpression/ClassOrInterfaceType[@Image='NullPointerException']
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]]>
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</value>
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</property>
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</properties>
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<example>
|
|||
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<![CDATA[
|
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public class Foo {
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void bar() {
|
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throw new NullPointerException();
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}
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|||
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}
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]]>
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</example>
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|||
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</rule>
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|||
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|
|||
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<rule name="AvoidThrowingRawExceptionTypes"
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language="java"
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since="1.8"
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message="Avoid throwing raw exception types."
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class="net.sourceforge.pmd.lang.rule.XPathRule"
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typeResolution="true"
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externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#avoidthrowingrawexceptiontypes">
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<description>
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|||
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Avoid throwing certain exception types. Rather than throw a raw RuntimeException, Throwable,
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Exception, or Error, use a subclassed exception or error instead.
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</description>
|
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<priority>1</priority>
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|||
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<properties>
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|||
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<property name="xpath">
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|||
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<value>
|
|||
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<![CDATA[
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//ThrowStatement//AllocationExpression
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/ClassOrInterfaceType[
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pmd-java:typeIsExactly('java.lang.Throwable')
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or
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pmd-java:typeIsExactly('java.lang.Exception')
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or
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pmd-java:typeIsExactly('java.lang.Error')
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or
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pmd-java:typeIsExactly('java.lang.RuntimeException')
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]
|
|||
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]]>
|
|||
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</value>
|
|||
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</property>
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|||
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</properties>
|
|||
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<example>
|
|||
|
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<![CDATA[
|
|||
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public class Foo {
|
|||
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public void bar() throws Exception {
|
|||
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throw new Exception();
|
|||
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}
|
|||
|
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}
|
|||
|
|
]]>
|
|||
|
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</example>
|
|||
|
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</rule>
|
|||
|
|
|
|||
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<rule name="ClassWithOnlyPrivateConstructorsShouldBeFinal"
|
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language="java"
|
|||
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since="4.1"
|
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class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
message="A class which only has private constructors should be final"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#classwithonlyprivateconstructorsshouldbefinal">
|
|||
|
|
<description>
|
|||
|
|
A class with only private constructors should be final, unless the private constructor
|
|||
|
|
is invoked by a inner class.
|
|||
|
|
</description>
|
|||
|
|
<priority>1</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
TypeDeclaration[count(../TypeDeclaration) = 1]/ClassOrInterfaceDeclaration
|
|||
|
|
[@Final = 'false']
|
|||
|
|
[count(./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration[@Private = 'true']) >= 1 ]
|
|||
|
|
[count(./ClassOrInterfaceBody/ClassOrInterfaceBodyDeclaration/ConstructorDeclaration[(@Public = 'true') or (@Protected = 'true') or (@PackagePrivate = 'true')]) = 0 ]
|
|||
|
|
[not(.//ClassOrInterfaceDeclaration)]
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo { //Should be final
|
|||
|
|
private Foo() { }
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="CollapsibleIfStatements"
|
|||
|
|
language="java"
|
|||
|
|
since="3.1"
|
|||
|
|
message="These nested if statements could be combined"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#collapsibleifstatements">
|
|||
|
|
<description>
|
|||
|
|
Sometimes two consecutive 'if' statements can be consolidated by separating their conditions with a boolean short-circuit operator.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//IfStatement[@Else='false']/Statement
|
|||
|
|
/IfStatement[@Else='false']
|
|||
|
|
|
|
|||
|
|
//IfStatement[@Else='false']/Statement
|
|||
|
|
/Block[count(BlockStatement)=1]/BlockStatement
|
|||
|
|
/Statement/IfStatement[@Else='false']
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
void bar() {
|
|||
|
|
if (x) { // original implementation
|
|||
|
|
if (y) {
|
|||
|
|
// do stuff
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
void bar() {
|
|||
|
|
if (x && y) { // optimized implementation
|
|||
|
|
// do stuff
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="CouplingBetweenObjects"
|
|||
|
|
since="1.04"
|
|||
|
|
message="High amount of different objects as members denotes a high coupling"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.CouplingBetweenObjectsRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#couplingbetweenobjects">
|
|||
|
|
<description>
|
|||
|
|
This rule counts the number of unique attributes, local variables, and return types within an object.
|
|||
|
|
A number higher than the specified threshold can indicate a high degree of coupling.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
import com.Blah;
|
|||
|
|
import org.Bar;
|
|||
|
|
import org.Bardo;
|
|||
|
|
|
|||
|
|
public class Foo {
|
|||
|
|
private Blah var1;
|
|||
|
|
private Bar var2;
|
|||
|
|
|
|||
|
|
//followed by many imports of unique objects
|
|||
|
|
void ObjectC doWork() {
|
|||
|
|
Bardo var55;
|
|||
|
|
ObjectA var44;
|
|||
|
|
ObjectZ var93;
|
|||
|
|
return something;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="CyclomaticComplexity"
|
|||
|
|
message="The {0} ''{1}'' has a{2} cyclomatic complexity of {3}."
|
|||
|
|
since="1.03"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.CyclomaticComplexityRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#cyclomaticcomplexity">
|
|||
|
|
<description><.
|
|||
|
|
|
|||
|
|
Generally, numbers ranging from 1-4 denote low complexity, 5-7 denote moderate complexity, 8-10 denote
|
|||
|
|
high complexity, and 11+ is very high complexity. By default, this rule reports methods with a complexity >= 10.
|
|||
|
|
Additionnally, classes with many methods of moderate complexity get reported as well once the total of their
|
|||
|
|
methods' complexities reaches 80, even if none of the methods was directly reported.
|
|||
|
|
|
|||
|
|
Reported methods should be broken down into several smaller methods. Reported classes should probably be broken down
|
|||
|
|
into subcomponents.]]>
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
class Foo {
|
|||
|
|
void baseCyclo() { // Cyclo = 1
|
|||
|
|
highCyclo();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
void highCyclo() { // Cyclo = 10: reported!
|
|||
|
|
int x = 0, y = 2;
|
|||
|
|
boolean a = false, b = true;
|
|||
|
|
|
|||
|
|
if (a && (y == 1 ? b : true)) { // +3
|
|||
|
|
if (y == x) { // +1
|
|||
|
|
while (true) { // +1
|
|||
|
|
if (x++ < 20) { // +1
|
|||
|
|
break; // +1
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
} else if (y == t && !d) { // +2
|
|||
|
|
x = a ? y : x; // +1
|
|||
|
|
} else {
|
|||
|
|
x = 2;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="DataClass"
|
|||
|
|
since="6.0.0"
|
|||
|
|
message="The class ''{0}'' is suspected to be a Data Class (WOC={1}, NOPA={2}, NOAM={3}, WMC={4})"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.DataClassRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#dataclass">
|
|||
|
|
<description>
|
|||
|
|
Data Classes are simple data holders, which reveal most of their state, and
|
|||
|
|
without complex functionality. The lack of functionality may indicate that
|
|||
|
|
their behaviour is defined elsewhere, which is a sign of poor data-behaviour
|
|||
|
|
proximity. By directly exposing their internals, Data Classes break encapsulation,
|
|||
|
|
and therefore reduce the system's maintainability and understandability. Moreover,
|
|||
|
|
classes tend to strongly rely on their data representation, which makes for a brittle
|
|||
|
|
design.
|
|||
|
|
|
|||
|
|
Refactoring a Data Class should focus on restoring a good data-behaviour proximity. In
|
|||
|
|
most cases, that means moving the operations defined on the data back into the class.
|
|||
|
|
In some other cases it may make sense to remove entirely the class and move the data
|
|||
|
|
into the former client classes.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class DataClass {
|
|||
|
|
|
|||
|
|
public int bar = 0;
|
|||
|
|
public int na = 0;
|
|||
|
|
private int bee = 0;
|
|||
|
|
|
|||
|
|
public void setBee(int n) {
|
|||
|
|
bee = n;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="DoNotExtendJavaLangError"
|
|||
|
|
language="java"
|
|||
|
|
typeResolution="true"
|
|||
|
|
since="4.0"
|
|||
|
|
message="Exceptions should not extend java.lang.Error"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#donotextendjavalangerror">
|
|||
|
|
<description>
|
|||
|
|
Errors are system exceptions. Do not extend them.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//ClassOrInterfaceDeclaration/ExtendsList/ClassOrInterfaceType
|
|||
|
|
[pmd-java:typeIs('java.lang.Error')]
|
|||
|
|
|
|||
|
|
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo extends Error { }
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ExceptionAsFlowControl"
|
|||
|
|
since="1.8"
|
|||
|
|
message="Avoid using exceptions as flow control."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ExceptionAsFlowControlRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#exceptionasflowcontrol">
|
|||
|
|
<description>
|
|||
|
|
Using Exceptions as form of flow control is not recommended as they obscure true exceptions when debugging.
|
|||
|
|
Either add the necessary validation or use an alternate control structure.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public void bar() {
|
|||
|
|
try {
|
|||
|
|
try {
|
|||
|
|
} catch (Exception e) {
|
|||
|
|
throw new WrapperException(e);
|
|||
|
|
// this is essentially a GOTO to the WrapperException catch block
|
|||
|
|
}
|
|||
|
|
} catch (WrapperException e) {
|
|||
|
|
// do some more stuff
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ExcessiveClassLength"
|
|||
|
|
since="0.6"
|
|||
|
|
message="Avoid really long classes."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ExcessiveClassLengthRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#excessiveclasslength">
|
|||
|
|
<description>
|
|||
|
|
Excessive class file lengths are usually indications that the class may be burdened with excessive
|
|||
|
|
responsibilities that could be provided by external classes or functions. In breaking these methods
|
|||
|
|
apart the code becomes more manageable and ripe for reuse.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
public void bar1() {
|
|||
|
|
// 1000 lines of code
|
|||
|
|
}
|
|||
|
|
public void bar2() {
|
|||
|
|
// 1000 lines of code
|
|||
|
|
}
|
|||
|
|
public void bar3() {
|
|||
|
|
// 1000 lines of code
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public void barN() {
|
|||
|
|
// 1000 lines of code
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ExcessiveImports"
|
|||
|
|
since="1.04"
|
|||
|
|
message="A high number of imports can indicate a high degree of coupling within an object."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ExcessiveImportsRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#excessiveimports">
|
|||
|
|
<description>
|
|||
|
|
A high number of imports can indicate a high degree of coupling within an object. This rule
|
|||
|
|
counts the number of unique imports and reports a violation if the count is above the
|
|||
|
|
user-specified threshold.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
import blah.blah.Baz;
|
|||
|
|
import blah.blah.Bif;
|
|||
|
|
// 18 others from the same package elided
|
|||
|
|
public class Foo {
|
|||
|
|
public void doWork() {}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ExcessiveMethodLength"
|
|||
|
|
since="0.6"
|
|||
|
|
message="Avoid really long methods."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ExcessiveMethodLengthRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#excessivemethodlength">
|
|||
|
|
<description>
|
|||
|
|
When methods are excessively long this usually indicates that the method is doing more than its
|
|||
|
|
name/signature might suggest. They also become challenging for others to digest since excessive
|
|||
|
|
scrolling causes readers to lose focus.
|
|||
|
|
Try to reduce the method length by creating helper methods and removing any copy/pasted code.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public void doSomething() {
|
|||
|
|
System.out.println("Hello world!");
|
|||
|
|
System.out.println("Hello world!");
|
|||
|
|
// 98 copies omitted for brevity.
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ExcessiveParameterList"
|
|||
|
|
since="0.9"
|
|||
|
|
message="Avoid long parameter lists."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ExcessiveParameterListRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#excessiveparameterlist">
|
|||
|
|
<description>
|
|||
|
|
Methods with numerous parameters are a challenge to maintain, especially if most of them share the
|
|||
|
|
same datatype. These situations usually denote the need for new objects to wrap the numerous parameters.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public void addPerson( // too many arguments liable to be mixed up
|
|||
|
|
int birthYear, int birthMonth, int birthDate, int height, int weight, int ssn) {
|
|||
|
|
|
|||
|
|
. . . .
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public void addPerson( // preferred approach
|
|||
|
|
Date birthdate, BodyMeasurements measurements, int ssn) {
|
|||
|
|
|
|||
|
|
. . . .
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ExcessivePublicCount"
|
|||
|
|
since="1.04"
|
|||
|
|
message="This class has a bunch of public methods and attributes"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ExcessivePublicCountRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#excessivepubliccount">
|
|||
|
|
<description>
|
|||
|
|
Classes with large numbers of public methods and attributes require disproportionate testing efforts
|
|||
|
|
since combinational side effects grow rapidly and increase risk. Refactoring these classes into
|
|||
|
|
smaller ones not only increases testability and reliability but also allows new variations to be
|
|||
|
|
developed easily.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
public String value;
|
|||
|
|
public Bar something;
|
|||
|
|
public Variable var;
|
|||
|
|
// [... more more public attributes ...]
|
|||
|
|
|
|||
|
|
public void doWork() {}
|
|||
|
|
public void doMoreWork() {}
|
|||
|
|
public void doWorkAgain() {}
|
|||
|
|
// [... more more public methods ...]
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="FinalFieldCouldBeStatic"
|
|||
|
|
language="java"
|
|||
|
|
since="1.1"
|
|||
|
|
message="This final field could be made static"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#finalfieldcouldbestatic">
|
|||
|
|
<description>
|
|||
|
|
If a final field is assigned to a compile-time constant, it could be made static, thus saving overhead
|
|||
|
|
in each object at runtime.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//FieldDeclaration
|
|||
|
|
[@Final='true' and @Static='false']
|
|||
|
|
/VariableDeclarator/VariableInitializer/Expression
|
|||
|
|
/PrimaryExpression[not(PrimarySuffix)]/PrimaryPrefix/Literal
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
public final int BAR = 42; // this could be static and save some space
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="GodClass"
|
|||
|
|
language="java"
|
|||
|
|
since="5.0"
|
|||
|
|
message="Possible God Class (WMC={0}, ATFD={2}, TCC={1})"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.GodClassRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#godclass">
|
|||
|
|
<description>
|
|||
|
|
The God Class rule detects the God Class design flaw using metrics. God classes do too many things,
|
|||
|
|
are very big and overly complex. They should be split apart to be more object-oriented.
|
|||
|
|
The rule uses the detection strategy described in "Object-Oriented Metrics in Practice".
|
|||
|
|
The violations are reported against the entire class.
|
|||
|
|
|
|||
|
|
See also the references:
|
|||
|
|
|
|||
|
|
Michele Lanza and Radu Marinescu. Object-Oriented Metrics in Practice:
|
|||
|
|
Using Software Metrics to Characterize, Evaluate, and Improve the Design
|
|||
|
|
of Object-Oriented Systems. Springer, Berlin, 1 edition, October 2006. Page 80.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ImmutableField"
|
|||
|
|
since="2.0"
|
|||
|
|
message="Private field ''{0}'' could be made final; it is only initialized in the declaration or constructor."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ImmutableFieldRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#immutablefield">
|
|||
|
|
<description>
|
|||
|
|
Identifies private fields whose values never change once object initialization ends either in the declaration
|
|||
|
|
of the field or by a constructor. This helps in converting existing classes to becoming immutable ones.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
private int x; // could be final
|
|||
|
|
public Foo() {
|
|||
|
|
x = 7;
|
|||
|
|
}
|
|||
|
|
public void foo() {
|
|||
|
|
int a = x + 2;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="LawOfDemeter"
|
|||
|
|
language="java"
|
|||
|
|
since="5.0"
|
|||
|
|
message="Potential violation of Law of Demeter"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.LawOfDemeterRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#lawofdemeter">
|
|||
|
|
<description>
|
|||
|
|
The Law of Demeter is a simple rule, that says "only talk to friends". It helps to reduce coupling between classes
|
|||
|
|
or objects.
|
|||
|
|
|
|||
|
|
See also the references:
|
|||
|
|
|
|||
|
|
* Andrew Hunt, David Thomas, and Ward Cunningham. The Pragmatic Programmer. From Journeyman to Master. Addison-Wesley Longman, Amsterdam, October 1999.;
|
|||
|
|
* K.J. Lieberherr and I.M. Holland. Assuring good style for object-oriented programs. Software, IEEE, 6(5):38–48, 1989.;
|
|||
|
|
* <http://www.ccs.neu.edu/home/lieber/LoD.html>
|
|||
|
|
* <http://en.wikipedia.org/wiki/Law_of_Demeter>
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
/**
|
|||
|
|
* This example will result in two violations.
|
|||
|
|
*/
|
|||
|
|
public void example(Bar b) {
|
|||
|
|
// this method call is ok, as b is a parameter of "example"
|
|||
|
|
C c = b.getC();
|
|||
|
|
|
|||
|
|
// this method call is a violation, as we are using c, which we got from B.
|
|||
|
|
// We should ask b directly instead, e.g. "b.doItOnC();"
|
|||
|
|
c.doIt();
|
|||
|
|
|
|||
|
|
// this is also a violation, just expressed differently as a method chain without temporary variables.
|
|||
|
|
b.getC().doIt();
|
|||
|
|
|
|||
|
|
// a constructor call, not a method call.
|
|||
|
|
D d = new D();
|
|||
|
|
// this method call is ok, because we have create the new instance of D locally.
|
|||
|
|
d.doSomethingElse();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="LogicInversion"
|
|||
|
|
language="java"
|
|||
|
|
since="5.0"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
message="Use opposite operator instead of the logic complement operator."
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#logicinversion">
|
|||
|
|
<description>
|
|||
|
|
Use opposite operator instead of negating the whole expression with a logic complement operator.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//UnaryExpressionNotPlusMinus[@Image='!']/PrimaryExpression/PrimaryPrefix/Expression[EqualityExpression or RelationalExpression]
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public boolean bar(int a, int b) {
|
|||
|
|
|
|||
|
|
if (!(a == b)) { // use !=
|
|||
|
|
return false;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
if (!(a < b)) { // use >=
|
|||
|
|
return false;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
return true;
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="LoosePackageCoupling"
|
|||
|
|
since="5.0"
|
|||
|
|
message="Use of ''{0}'' outside of package hierarchy ''{1}'' is not recommended; use recommended classes instead"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.LoosePackageCouplingRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#loosepackagecoupling">
|
|||
|
|
<description>
|
|||
|
|
Avoid using classes from the configured package hierarchy outside of the package hierarchy,
|
|||
|
|
except when using one of the configured allowed classes.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
package some.package;
|
|||
|
|
|
|||
|
|
import some.other.package.subpackage.subsubpackage.DontUseThisClass;
|
|||
|
|
|
|||
|
|
public class Bar {
|
|||
|
|
DontUseThisClass boo = new DontUseThisClass();
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="ModifiedCyclomaticComplexity"
|
|||
|
|
since="5.1.2"
|
|||
|
|
message = "The {0} ''{1}'' has a Modified Cyclomatic Complexity of {2}."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.ModifiedCyclomaticComplexityRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#modifiedcyclomaticcomplexity"
|
|||
|
|
deprecated="true">
|
|||
|
|
<description>
|
|||
|
|
Complexity directly affects maintenance costs is determined by the number of decision points in a method
|
|||
|
|
plus one for the method entry. The decision points include 'if', 'while', 'for', and 'case labels' calls.
|
|||
|
|
Generally, numbers ranging from 1-4 denote low complexity, 5-7 denote moderate complexity, 8-10 denote
|
|||
|
|
high complexity, and 11+ is very high complexity. Modified complexity treats switch statements as a single
|
|||
|
|
decision point.
|
|||
|
|
|
|||
|
|
This rule is deprecated and will be removed with PMD 7.0.0. The rule is replaced
|
|||
|
|
by the rule {% rule java/design/CyclomaticComplexity %}.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo { // This has a Cyclomatic Complexity = 9
|
|||
|
|
1 public void example() {
|
|||
|
|
2 if (a == b) {
|
|||
|
|
3 if (a1 == b1) {
|
|||
|
|
fiddle();
|
|||
|
|
4 } else if a2 == b2) {
|
|||
|
|
fiddle();
|
|||
|
|
} else {
|
|||
|
|
fiddle();
|
|||
|
|
}
|
|||
|
|
5 } else if (c == d) {
|
|||
|
|
6 while (c == d) {
|
|||
|
|
fiddle();
|
|||
|
|
}
|
|||
|
|
7 } else if (e == f) {
|
|||
|
|
8 for (int n = 0; n < h; n++) {
|
|||
|
|
fiddle();
|
|||
|
|
}
|
|||
|
|
} else{
|
|||
|
|
9 switch (z) {
|
|||
|
|
case 1:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
case 2:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
case 3:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
default:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="NcssConstructorCount"
|
|||
|
|
message="The constructor with {0} parameters has an NCSS line count of {1}"
|
|||
|
|
since="3.9"
|
|||
|
|
deprecated="true"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.NcssConstructorCountRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#ncssconstructorcount">
|
|||
|
|
<description>
|
|||
|
|
This rule uses the NCSS (Non-Commenting Source Statements) algorithm to determine the number of lines
|
|||
|
|
of code for a given constructor. NCSS ignores comments, and counts actual statements. Using this algorithm,
|
|||
|
|
lines of code that are split are counted as one.
|
|||
|
|
|
|||
|
|
This rule is deprecated and will be removed with PMD 7.0.0. The rule is replaced
|
|||
|
|
by the rule {% rule java/design/NcssCount %}.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo extends Bar {
|
|||
|
|
public Foo() {
|
|||
|
|
super();
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
//this constructor only has 1 NCSS lines
|
|||
|
|
super.foo();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="NcssCount"
|
|||
|
|
message="The {0} ''{1}'' has a NCSS line count of {2}."
|
|||
|
|
since="6.0.0"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.NcssCountRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#ncsscount">
|
|||
|
|
<description>
|
|||
|
|
This rule uses the NCSS (Non-Commenting Source Statements) metric to determine the number of lines
|
|||
|
|
of code in a class, method or constructor. NCSS ignores comments, blank lines, and only counts actual
|
|||
|
|
statements. For more details on the calculation, see the documentation of
|
|||
|
|
the [NCSS metric](/pmd_java_metrics_index.html#non-commenting-source-statements-ncss).
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
import java.util.Collections; // +0
|
|||
|
|
import java.io.IOException; // +0
|
|||
|
|
|
|||
|
|
class Foo { // +1, total Ncss = 12
|
|||
|
|
|
|||
|
|
public void bigMethod() // +1
|
|||
|
|
throws IOException {
|
|||
|
|
int x = 0, y = 2; // +1
|
|||
|
|
boolean a = false, b = true; // +1
|
|||
|
|
|
|||
|
|
if (a || b) { // +1
|
|||
|
|
try { // +1
|
|||
|
|
do { // +1
|
|||
|
|
x += 2; // +1
|
|||
|
|
} while (x < 12);
|
|||
|
|
|
|||
|
|
System.exit(0); // +1
|
|||
|
|
} catch (IOException ioe) { // +1
|
|||
|
|
throw new PatheticFailException(ioe); // +1
|
|||
|
|
}
|
|||
|
|
} else {
|
|||
|
|
assert false; // +1
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="NcssMethodCount"
|
|||
|
|
message="The method {0}() has an NCSS line count of {1}"
|
|||
|
|
deprecated="true"
|
|||
|
|
since="3.9"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.NcssMethodCountRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#ncssmethodcount">
|
|||
|
|
<description>
|
|||
|
|
This rule uses the NCSS (Non-Commenting Source Statements) algorithm to determine the number of lines
|
|||
|
|
of code for a given method. NCSS ignores comments, and counts actual statements. Using this algorithm,
|
|||
|
|
lines of code that are split are counted as one.
|
|||
|
|
|
|||
|
|
This rule is deprecated and will be removed with PMD 7.0.0. The rule is replaced
|
|||
|
|
by the rule {% rule java/design/NcssCount %}.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo extends Bar {
|
|||
|
|
public int methd() {
|
|||
|
|
super.methd();
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
//this method only has 1 NCSS lines
|
|||
|
|
return 1;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="NcssTypeCount"
|
|||
|
|
message="The type has an NCSS line count of {0}"
|
|||
|
|
since="3.9"
|
|||
|
|
deprecated="true"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.NcssTypeCountRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#ncsstypecount">
|
|||
|
|
<description>
|
|||
|
|
This rule uses the NCSS (Non-Commenting Source Statements) algorithm to determine the number of lines
|
|||
|
|
of code for a given type. NCSS ignores comments, and counts actual statements. Using this algorithm,
|
|||
|
|
lines of code that are split are counted as one.
|
|||
|
|
|
|||
|
|
This rule is deprecated and will be removed with PMD 7.0.0. The rule is replaced
|
|||
|
|
by the rule {% rule java/design/NcssCount %}.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo extends Bar {
|
|||
|
|
public Foo() {
|
|||
|
|
//this class only has 6 NCSS lines
|
|||
|
|
super();
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
|
|||
|
|
super.foo();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="NPathComplexity"
|
|||
|
|
since="3.9"
|
|||
|
|
message="The {0} ''{1}'' has an NPath complexity of {2}"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.NPathComplexityRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#npathcomplexity">
|
|||
|
|
<description>
|
|||
|
|
The NPath complexity of a method is the number of acyclic execution paths through that method.
|
|||
|
|
While cyclomatic complexity counts the number of decision points in a method, NPath counts the number of
|
|||
|
|
full paths from the beginning to the end of the block of the method. That metric grows exponentially, as
|
|||
|
|
it multiplies the complexity of statements in the same block. For more details on the calculation, see the
|
|||
|
|
documentation of the [NPath metric](/pmd_java_metrics_index.html#npath-complexity-npath).
|
|||
|
|
|
|||
|
|
A threshold of 200 is generally considered the point where measures should be taken to reduce
|
|||
|
|
complexity and increase readability.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
public static void bar() { // Ncss = 252: reported!
|
|||
|
|
boolean a, b = true;
|
|||
|
|
try { // 2 * 2 + 2 = 6
|
|||
|
|
if (true) { // 2
|
|||
|
|
List buz = new ArrayList();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
for(int i = 0; i < 19; i++) { // * 2
|
|||
|
|
List buz = new ArrayList();
|
|||
|
|
}
|
|||
|
|
} catch(Exception e) {
|
|||
|
|
if (true) { // 2
|
|||
|
|
e.printStackTrace();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
while (j++ < 20) { // * 2
|
|||
|
|
List buz = new ArrayList();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
switch(j) { // * 7
|
|||
|
|
case 1:
|
|||
|
|
case 2: break;
|
|||
|
|
case 3: j = 5; break;
|
|||
|
|
case 4: if (b && a) { bar(); } break;
|
|||
|
|
default: break;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
do { // * 3
|
|||
|
|
List buz = new ArrayList();
|
|||
|
|
} while (a && j++ < 30);
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SignatureDeclareThrowsException"
|
|||
|
|
since="1.2"
|
|||
|
|
message="A method/constructor should not explicitly throw java.lang.Exception"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.SignatureDeclareThrowsExceptionRule"
|
|||
|
|
typeResolution="true"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#signaturedeclarethrowsexception">
|
|||
|
|
<description>
|
|||
|
|
A method/constructor shouldn't explicitly throw the generic java.lang.Exception, since it
|
|||
|
|
is unclear which exceptions that can be thrown from the methods. It might be
|
|||
|
|
difficult to document and understand such vague interfaces. Use either a class
|
|||
|
|
derived from RuntimeException or a checked exception.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public void foo() throws Exception {
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SimplifiedTernary"
|
|||
|
|
language="java"
|
|||
|
|
since="5.4.0"
|
|||
|
|
message="Ternary operators that can be simplified with || or &&"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#simplifiedternary">
|
|||
|
|
<description>
|
|||
|
|
<![CDATA[
|
|||
|
|
Look for ternary operators with the form `condition ? literalBoolean : foo`
|
|||
|
|
or `condition ? foo : literalBoolean`.
|
|||
|
|
|
|||
|
|
These expressions can be simplified respectively to
|
|||
|
|
`condition || foo` when the literalBoolean is true
|
|||
|
|
`!condition && foo` when the literalBoolean is false
|
|||
|
|
or
|
|||
|
|
`!condition || foo` when the literalBoolean is true
|
|||
|
|
`condition && foo` when the literalBoolean is false
|
|||
|
|
]]>
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//ConditionalExpression[not(PrimaryExpression/*/Literal) and (Expression/PrimaryExpression/*/Literal/BooleanLiteral)]
|
|||
|
|
|
|
|||
|
|
//ConditionalExpression[not(Expression/PrimaryExpression/*/Literal) and (PrimaryExpression/*/Literal/BooleanLiteral)]
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
public boolean test() {
|
|||
|
|
return condition ? true : something(); // can be as simple as return condition || something();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public void test2() {
|
|||
|
|
final boolean value = condition ? false : something(); // can be as simple as value = !condition && something();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public boolean test3() {
|
|||
|
|
return condition ? something() : true; // can be as simple as return !condition || something();
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public void test4() {
|
|||
|
|
final boolean otherValue = condition ? something() : false; // can be as simple as condition && something();
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SimplifyBooleanAssertion"
|
|||
|
|
language="java"
|
|||
|
|
since="3.6"
|
|||
|
|
message="assertTrue(!expr) can be replaced by assertFalse(expr)"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
typeResolution="true"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#simplifybooleanassertion">
|
|||
|
|
<description>
|
|||
|
|
Avoid negation in an assertTrue or assertFalse test.
|
|||
|
|
|
|||
|
|
For example, rephrase:
|
|||
|
|
|
|||
|
|
assertTrue(!expr);
|
|||
|
|
|
|||
|
|
as:
|
|||
|
|
|
|||
|
|
assertFalse(expr);
|
|||
|
|
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//StatementExpression
|
|||
|
|
[
|
|||
|
|
.//Name[@Image='assertTrue' or @Image='assertFalse']
|
|||
|
|
and
|
|||
|
|
PrimaryExpression/PrimarySuffix/Arguments/ArgumentList
|
|||
|
|
/Expression/UnaryExpressionNotPlusMinus[@Image='!']
|
|||
|
|
/PrimaryExpression/PrimaryPrefix
|
|||
|
|
]
|
|||
|
|
[ancestor::ClassOrInterfaceDeclaration[//ClassOrInterfaceType[pmd-java:typeIs('junit.framework.TestCase')]
|
|||
|
|
or //MarkerAnnotation/Name[
|
|||
|
|
pmd-java:typeIs('org.junit.Test')
|
|||
|
|
or pmd-java:typeIs('org.junit.jupiter.api.Test') or pmd-java:typeIs('org.junit.jupiter.api.RepeatedTest')
|
|||
|
|
or pmd-java:typeIs('org.junit.jupiter.api.TestFactory') or pmd-java:typeIs('org.junit.jupiter.api.TestTemplate')
|
|||
|
|
or pmd-java:typeIs('org.junit.jupiter.params.ParameterizedTest')
|
|||
|
|
]
|
|||
|
|
]]]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class SimpleTest extends TestCase {
|
|||
|
|
public void testX() {
|
|||
|
|
assertTrue("not empty", !r.isEmpty()); // replace with assertFalse("not empty", r.isEmpty())
|
|||
|
|
assertFalse(!r.isEmpty()); // replace with assertTrue(r.isEmpty())
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SimplifyBooleanExpressions"
|
|||
|
|
language="java"
|
|||
|
|
since="1.05"
|
|||
|
|
message="Avoid unnecessary comparisons in boolean expressions"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#simplifybooleanexpressions">
|
|||
|
|
<description>
|
|||
|
|
Avoid unnecessary comparisons in boolean expressions, they serve no purpose and impacts readability.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//EqualityExpression/PrimaryExpression
|
|||
|
|
/PrimaryPrefix/Literal/BooleanLiteral
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Bar {
|
|||
|
|
// can be simplified to
|
|||
|
|
// bar = isFoo();
|
|||
|
|
private boolean bar = (isFoo() == true);
|
|||
|
|
|
|||
|
|
public isFoo() { return false;}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SimplifyBooleanReturns"
|
|||
|
|
since="0.9"
|
|||
|
|
message="Avoid unnecessary if..then..else statements when returning booleans"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.SimplifyBooleanReturnsRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#simplifybooleanreturns">
|
|||
|
|
<description>
|
|||
|
|
Avoid unnecessary if-then-else statements when returning a boolean. The result of
|
|||
|
|
the conditional test can be returned instead.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public boolean isBarEqualTo(int x) {
|
|||
|
|
if (bar == x) { // this bit of code...
|
|||
|
|
return true;
|
|||
|
|
} else {
|
|||
|
|
return false;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public boolean isBarEqualTo(int x) {
|
|||
|
|
return bar == x; // can be replaced with this
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SimplifyConditional"
|
|||
|
|
language="java"
|
|||
|
|
since="3.1"
|
|||
|
|
message="No need to check for null before an instanceof"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#simplifyconditional">
|
|||
|
|
<description>
|
|||
|
|
No need to check for null before an instanceof; the instanceof keyword returns false when given a null argument.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//Expression
|
|||
|
|
[ConditionalOrExpression
|
|||
|
|
[EqualityExpression[@Image='==']
|
|||
|
|
//NullLiteral
|
|||
|
|
and
|
|||
|
|
UnaryExpressionNotPlusMinus
|
|||
|
|
[@Image='!']//InstanceOfExpression[PrimaryExpression
|
|||
|
|
//Name/@Image = ancestor::ConditionalOrExpression/EqualityExpression
|
|||
|
|
/PrimaryExpression/PrimaryPrefix/Name/@Image]
|
|||
|
|
and
|
|||
|
|
(count(UnaryExpressionNotPlusMinus) + 1 = count(*))
|
|||
|
|
]
|
|||
|
|
or
|
|||
|
|
ConditionalAndExpression
|
|||
|
|
[EqualityExpression[@Image='!=']//NullLiteral
|
|||
|
|
and
|
|||
|
|
InstanceOfExpression
|
|||
|
|
[PrimaryExpression[count(PrimarySuffix[@ArrayDereference='true'])=0]
|
|||
|
|
//Name[not(contains(@Image,'.'))]/@Image = ancestor::ConditionalAndExpression
|
|||
|
|
/EqualityExpression/PrimaryExpression/PrimaryPrefix/Name/@Image]
|
|||
|
|
and
|
|||
|
|
(count(InstanceOfExpression) + 1 = count(*))
|
|||
|
|
]
|
|||
|
|
]
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
class Foo {
|
|||
|
|
void bar(Object x) {
|
|||
|
|
if (x != null && x instanceof Bar) {
|
|||
|
|
// just drop the "x != null" check
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SingularField"
|
|||
|
|
since="3.1"
|
|||
|
|
message="Perhaps ''{0}'' could be replaced by a local variable."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.SingularFieldRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#singularfield">
|
|||
|
|
<description>
|
|||
|
|
Fields whose scopes are limited to just single methods do not rely on the containing
|
|||
|
|
object to provide them to other methods. They may be better implemented as local variables
|
|||
|
|
within those methods.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
private int x; // no reason to exist at the Foo instance level
|
|||
|
|
public void foo(int y) {
|
|||
|
|
x = y + 5;
|
|||
|
|
return x;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="StdCyclomaticComplexity"
|
|||
|
|
since="5.1.2"
|
|||
|
|
message = "The {0} ''{1}'' has a Standard Cyclomatic Complexity of {2}."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.StdCyclomaticComplexityRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#stdcyclomaticcomplexity"
|
|||
|
|
deprecated="true">
|
|||
|
|
<description>
|
|||
|
|
Complexity directly affects maintenance costs is determined by the number of decision points in a method
|
|||
|
|
plus one for the method entry. The decision points include 'if', 'while', 'for', and 'case labels' calls.
|
|||
|
|
Generally, numbers ranging from 1-4 denote low complexity, 5-7 denote moderate complexity, 8-10 denote
|
|||
|
|
high complexity, and 11+ is very high complexity.
|
|||
|
|
|
|||
|
|
This rule is deprecated and will be removed with PMD 7.0.0. The rule is replaced
|
|||
|
|
by the rule {% rule java/design/CyclomaticComplexity %}.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo { // This has a Cyclomatic Complexity = 12
|
|||
|
|
1 public void example() {
|
|||
|
|
2 if (a == b || (c == d && e == f)) { // Only one
|
|||
|
|
3 if (a1 == b1) {
|
|||
|
|
fiddle();
|
|||
|
|
4 } else if a2 == b2) {
|
|||
|
|
fiddle();
|
|||
|
|
} else {
|
|||
|
|
fiddle();
|
|||
|
|
}
|
|||
|
|
5 } else if (c == d) {
|
|||
|
|
6 while (c == d) {
|
|||
|
|
fiddle();
|
|||
|
|
}
|
|||
|
|
7 } else if (e == f) {
|
|||
|
|
8 for (int n = 0; n < h; n++) {
|
|||
|
|
fiddle();
|
|||
|
|
}
|
|||
|
|
} else{
|
|||
|
|
switch (z) {
|
|||
|
|
9 case 1:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
10 case 2:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
11 case 3:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
12 default:
|
|||
|
|
fiddle();
|
|||
|
|
break;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="SwitchDensity"
|
|||
|
|
since="1.02"
|
|||
|
|
message="A high ratio of statements to labels in a switch statement. Consider refactoring."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.SwitchDensityRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#switchdensity">
|
|||
|
|
<description>
|
|||
|
|
A high ratio of statements to labels in a switch statement implies that the switch statement
|
|||
|
|
is overloaded. Consider moving the statements into new methods or creating subclasses based
|
|||
|
|
on the switch variable.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Foo {
|
|||
|
|
public void bar(int x) {
|
|||
|
|
switch (x) {
|
|||
|
|
case 1: {
|
|||
|
|
// lots of statements
|
|||
|
|
break;
|
|||
|
|
} case 2: {
|
|||
|
|
// lots of statements
|
|||
|
|
break;
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="TooManyFields"
|
|||
|
|
since="3.0"
|
|||
|
|
message="Too many fields"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.TooManyFieldsRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#toomanyfields">
|
|||
|
|
<description>
|
|||
|
|
Classes that have too many fields can become unwieldy and could be redesigned to have fewer fields,
|
|||
|
|
possibly through grouping related fields in new objects. For example, a class with individual
|
|||
|
|
city/state/zip fields could park them within a single Address field.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class Person { // too many separate fields
|
|||
|
|
int birthYear;
|
|||
|
|
int birthMonth;
|
|||
|
|
int birthDate;
|
|||
|
|
float height;
|
|||
|
|
float weight;
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public class Person { // this is more manageable
|
|||
|
|
Date birthDate;
|
|||
|
|
BodyMeasurements measurements;
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="TooManyMethods"
|
|||
|
|
language="java"
|
|||
|
|
since="4.2"
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
message="This class has too many methods, consider refactoring it."
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#toomanymethods">
|
|||
|
|
<description>
|
|||
|
|
A class with too many methods is probably a good suspect for refactoring, in order to reduce its
|
|||
|
|
complexity and find a way to have more fine grained objects.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="maxmethods" type="Integer" description="The method count reporting threshold" min="1" max="1000" value="10"/>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<!-- FIXME: Refine XPath to discard 'get' and 'set' methods with Block no more than 3 lines,
|
|||
|
|
something like this:
|
|||
|
|
not (
|
|||
|
|
(
|
|||
|
|
starts-with(@Image,'get')
|
|||
|
|
or
|
|||
|
|
starts-with(@Image,'set')
|
|||
|
|
or
|
|||
|
|
starts-with(@Image,'is')
|
|||
|
|
)
|
|||
|
|
and (
|
|||
|
|
(
|
|||
|
|
(../Block/attribute::endLine)
|
|||
|
|
-
|
|||
|
|
(../Block/attribute::beginLine)
|
|||
|
|
) <= 3
|
|||
|
|
)
|
|||
|
|
)
|
|||
|
|
This will avoid discarding 'real' method...
|
|||
|
|
-->
|
|||
|
|
<![CDATA[
|
|||
|
|
//ClassOrInterfaceDeclaration/ClassOrInterfaceBody
|
|||
|
|
[
|
|||
|
|
count(./ClassOrInterfaceBodyDeclaration/MethodDeclaration/MethodDeclarator[
|
|||
|
|
not (
|
|||
|
|
starts-with(@Image,'get')
|
|||
|
|
or
|
|||
|
|
starts-with(@Image,'set')
|
|||
|
|
or
|
|||
|
|
starts-with(@Image,'is')
|
|||
|
|
)
|
|||
|
|
]) > $maxmethods
|
|||
|
|
]
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="UselessOverridingMethod"
|
|||
|
|
since="3.3"
|
|||
|
|
message="Overriding method merely calls super"
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.UselessOverridingMethodRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#uselessoverridingmethod">
|
|||
|
|
<description>
|
|||
|
|
The overriding method merely calls the same method defined in a superclass.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public void foo(String bar) {
|
|||
|
|
super.foo(bar); // why bother overriding?
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
public String foo() {
|
|||
|
|
return super.foo(); // why bother overriding?
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
@Id
|
|||
|
|
public Long getId() {
|
|||
|
|
return super.getId(); // OK if 'ignoreAnnotations' is false, which is the default behavior
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="UseObjectForClearerAPI"
|
|||
|
|
language="java"
|
|||
|
|
since="4.2.6"
|
|||
|
|
message="Rather than using a lot of String arguments, consider using a container object for those values."
|
|||
|
|
class="net.sourceforge.pmd.lang.rule.XPathRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#useobjectforclearerapi">
|
|||
|
|
<description>
|
|||
|
|
When you write a public method, you should be thinking in terms of an API. If your method is public, it means other class
|
|||
|
|
will use it, therefore, you want (or need) to offer a comprehensive and evolutive API. If you pass a lot of information
|
|||
|
|
as a simple series of Strings, you may think of using an Object to represent all those information. You'll get a simpler
|
|||
|
|
API (such as doWork(Workload workload), rather than a tedious series of Strings) and more importantly, if you need at some
|
|||
|
|
point to pass extra data, you'll be able to do so by simply modifying or extending Workload without any modification to
|
|||
|
|
your API.
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<properties>
|
|||
|
|
<property name="xpath">
|
|||
|
|
<value>
|
|||
|
|
<![CDATA[
|
|||
|
|
//MethodDeclaration[@Public]/MethodDeclarator/FormalParameters[
|
|||
|
|
count(FormalParameter/Type/ReferenceType/ClassOrInterfaceType[@Image = 'String']) > 3
|
|||
|
|
]
|
|||
|
|
]]>
|
|||
|
|
</value>
|
|||
|
|
</property>
|
|||
|
|
</properties>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class MyClass {
|
|||
|
|
public void connect(String username,
|
|||
|
|
String pssd,
|
|||
|
|
String databaseName,
|
|||
|
|
String databaseAdress)
|
|||
|
|
// Instead of those parameters object
|
|||
|
|
// would ensure a cleaner API and permit
|
|||
|
|
// to add extra data transparently (no code change):
|
|||
|
|
// void connect(UserData data);
|
|||
|
|
{
|
|||
|
|
|
|||
|
|
}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
<rule name="UseUtilityClass"
|
|||
|
|
since="0.3"
|
|||
|
|
message="All methods are static. Consider using a utility class instead. Alternatively, you could add a private constructor or make the class abstract to silence this warning."
|
|||
|
|
class="net.sourceforge.pmd.lang.java.rule.design.UseUtilityClassRule"
|
|||
|
|
externalInfoUrl="${pmd.website.baseurl}/pmd_rules_java_design.html#useutilityclass">
|
|||
|
|
<description>
|
|||
|
|
For classes that only have static methods, consider making them utility classes.
|
|||
|
|
Note that this doesn't apply to abstract classes, since their subclasses may
|
|||
|
|
well include non-static methods. Also, if you want this class to be a utility class,
|
|||
|
|
remember to add a private constructor to prevent instantiation.
|
|||
|
|
(Note, that this use was known before PMD 5.1.0 as UseSingleton).
|
|||
|
|
</description>
|
|||
|
|
<priority>3</priority>
|
|||
|
|
<example>
|
|||
|
|
<![CDATA[
|
|||
|
|
public class MaybeAUtility {
|
|||
|
|
public static void foo() {}
|
|||
|
|
public static void bar() {}
|
|||
|
|
}
|
|||
|
|
]]>
|
|||
|
|
</example>
|
|||
|
|
</rule>
|
|||
|
|
|
|||
|
|
</ruleset>
|