allow single subfield value transformation

build.gradle

@@ -13,7 +13,7 @@ apply plugin: 'checkstyle'
 apply plugin: "jacoco"
 
 group = "org.xbib"
-version = "1.0.5"
+version = "1.0.6"
 
 configurations {
     wagon

src/main/java/org/xbib/marc/MarcField.java

@@ -224,13 +224,12 @@ public class MarcField implements Comparable<MarcField> {
 
     /**
      * A MARC field can be denoted by a key, independent of values.
-     * This key is a string, consisting of tag, indicator, subfield IDs, delimited by a dollar sign.
+     * This key is a string, consisting of the tag.
      *
-     * @return the key of this MARC field
+     * @return the tag-based key of this MARC field
      */
-    public String toKey() {
+    public String toTagKey() {
-        return (tag == null ? EMPTY_STRING : tag) + KEY_DELIMITER + (indicator == null ? EMPTY_STRING : indicator) +
+        return tag == null ? EMPTY_STRING : tag;
-                KEY_DELIMITER + subfieldIds;
     }
 
     /**
@@ -244,13 +243,22 @@ public class MarcField implements Comparable<MarcField> {
     }
 
     /**
-     * A MARC field can be denoted by a key, independent of values.
+     * Return subfield IDs.
-     * This key is a string, consisting of the tag.
+     * @return the subfield ID list as a string.
-     *
-     * @return the tag-based key of this MARC field
      */
-    public String toTagKey() {
+    public String getSubfieldIds() {
-        return tag == null ? EMPTY_STRING : tag;
+        return subfieldIds;
+    }
+
+    /**
+     * A MARC field can be denoted by a key, independent of values.
+     * This key is a string, consisting of tag, indicator, subfield IDs, delimited by a dollar sign.
+     *
+     * @return the key of this MARC field
+     */
+    public String toKey() {
+        return (tag == null ? EMPTY_STRING : tag) + KEY_DELIMITER + (indicator == null ? EMPTY_STRING : indicator) +
+                KEY_DELIMITER + subfieldIds;
     }
 
     @Override

src/main/java/org/xbib/marc/transformer/value/MarcValueTransformers.java

@@ -27,6 +27,8 @@ public class MarcValueTransformers {
 
     private final Map<String, MarcValueTransformer> marcValueTransformerMap = new HashMap<>();
 
+    private final Map<String, String> subfieldMap = new HashMap<>();
+
     public MarcValueTransformers setMarcValueTransformer(MarcValueTransformer transformer) {
         this.marcValueTransformerMap.put("_default", transformer);
         return this;
@@ -39,7 +41,13 @@ public class MarcValueTransformers {
      * @return this handler
      */
     public MarcValueTransformers setMarcValueTransformer(String fieldKey, MarcValueTransformer transformer) {
-        this.marcValueTransformerMap.put(fieldKey, transformer);
+        // split into  tag + indicator and subfield IDs
+        int pos = fieldKey.lastIndexOf('$');
+        String tagind = pos > 0 ? fieldKey.substring(0, pos) : fieldKey;
+        String subs = pos > 0 ? fieldKey.substring(pos + 1) : "";
+        this.marcValueTransformerMap.put(tagind, transformer);
+        // subfield IDs
+        this.subfieldMap.put(tagind, subs);
         return this;
     }
 
@@ -49,7 +57,7 @@ public class MarcValueTransformers {
      * @return a new MARC field with transformed values
      */
     public MarcField transformValue(MarcField field) {
-        String key = field.toKey();
+        String key = field.toTagIndicatorKey();
         if (marcValueTransformerMap.isEmpty()) {
             return field;
         }
@@ -61,8 +69,11 @@ public class MarcValueTransformers {
             if (field.getValue() != null) {
                 builder.value(transformer.transform(field.getValue()));
             }
+            // select only subfields configured for this tag
+            String subs = subfieldMap.containsKey(key) ? subfieldMap.get(key) : field.getSubfieldIds();
             field.getSubfields().forEach(subfield ->
-                    builder.subfield(subfield.getId(), transformer.transform(subfield.getValue())));
+                    builder.subfield(subfield.getId(), subs.contains(subfield.getId()) ?
+                                    transformer.transform(subfield.getValue()) : subfield.getValue()));
             return builder.build();
         }
         return field;

src/test/java/org/xbib/marc/transformer/MarcValueTransformerTest.java

@@ -14,12 +14,7 @@ public class MarcValueTransformerTest {
 
     @Test
     public void testValueTransformer() {
-        MarcValueTransformer marcValueTransformer = new MarcValueTransformer() {
+        MarcValueTransformer marcValueTransformer = value -> value.equals("World") ? "Earth" : value;
-            @Override
-            public String transform(String value) {
-                return value.equals("World") ? "Earth" : value;
-            }
-        };
         MarcValueTransformers marcValueTransformers = new MarcValueTransformers();
         marcValueTransformers.setMarcValueTransformer(marcValueTransformer);
         MarcField a = MarcField.builder().tag("100").subfield("a", "Hello").subfield("b", "World").build();
@@ -29,12 +24,7 @@ public class MarcValueTransformerTest {
 
     @Test
     public void testValueControlFieldTransformer() {
-        MarcValueTransformer marcValueTransformer = new MarcValueTransformer() {
+        MarcValueTransformer marcValueTransformer = value -> value.equals("World") ? "Earth" : value;
-            @Override
-            public String transform(String value) {
-                return value.equals("World") ? "Earth" : value;
-            }
-        };
         MarcValueTransformers marcValueTransformers = new MarcValueTransformers();
         marcValueTransformers.setMarcValueTransformer(marcValueTransformer);
         MarcField a = MarcField.builder().tag("001").value("World").build();
@@ -42,4 +32,29 @@ public class MarcValueTransformerTest {
         assertEquals("001$$Earth", b.toString());
     }
 
+    @Test
+    public void testValueTransformerForSingleSubfield() {
+        MarcValueTransformer marcValueTransformer = value -> value.equals("World") ? "Earth" : value;
+        MarcValueTransformers marcValueTransformers = new MarcValueTransformers();
+        // select only subfield 'b' for transformation
+        marcValueTransformers.setMarcValueTransformer("100$$b", marcValueTransformer);
+        // create MARC field with two subfields
+        MarcField a = MarcField.builder().tag("100").subfield("a", "World").subfield("b", "World").build();
+        MarcField b = marcValueTransformers.transformValue(a);
+        // check that transformation has been applied only to subfield 'b'
+        assertEquals("100$$ab[a=World, b=Earth]", b.toString());
+    }
+    @Test
+    public void testValueTransformerForManySubfields() {
+        MarcValueTransformer marcValueTransformer = value -> value.equals("World") ? "Earth" : value;
+        MarcValueTransformers marcValueTransformers = new MarcValueTransformers();
+        // select subfield 'a' and 'b' for transformation
+        marcValueTransformers.setMarcValueTransformer("100$$ab", marcValueTransformer);
+        // create MARC field with two subfields
+        MarcField a = MarcField.builder().tag("100").subfield("a", "World").subfield("b", "World").build();
+        MarcField b = marcValueTransformers.transformValue(a);
+        // check that transformation has been applied to both subfields
+        assertEquals("100$$ab[a=Earth, b=Earth]", b.toString());
+    }
+
 }