add close() method to Ghostscript

gradle.properties

@@ -1,5 +1,5 @@
 group = org.xbib.graphics
 name = graphics
-version = 4.3.2
+version = 4.3.3
 
 org.gradle.warning.mode = ALL

graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/FontAnalyzer.java

@@ -23,9 +23,9 @@ public class FontAnalyzer {
                 "-sFile=" + path.toAbsolutePath(),
                 "-sOutputFile=%stdout",
                 "-f", "-"};
+        Ghostscript gs = Ghostscript.getInstance();
         try (InputStream is = this.getClass().getClassLoader().getResourceAsStream("script/AnalyzePDFFonts.ps");
              ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
-            Ghostscript gs = Ghostscript.getInstance();
             gs.setStdIn(is);
             gs.setStdOut(baos);
             gs.run(gsArgs);
@@ -56,6 +56,8 @@ public class FontAnalyzer {
                 }
             }
             return result;
+        } finally {
+            gs.close();
         }
     }
 }

graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/Ghostscript.java

@@ -31,32 +31,24 @@ public class Ghostscript {
 
     private static Ghostscript INSTANCE;
 
-    private static InputStream stdIn;
+    private InputStream stdIn;
 
-    private static OutputStream stdOut;
+    private OutputStream stdOut;
 
-    private static OutputStream stdErr;
+    private OutputStream stdErr;
 
-    static {
+    private GhostscriptLibrary libraryInstance;
-        try {
+
-            prepareTmp();
+    private Ghostscript(GhostscriptLibrary libraryInstance) {
-            INSTANCE = new Ghostscript();
+        this.libraryInstance = libraryInstance;
-            stdOut = new LoggingOutputStream(logger);
+        this.stdOut = new LoggingOutputStream(logger);
-            stdErr = new LoggingOutputStream(logger);
+        this.stdErr = new LoggingOutputStream(logger);
-            INSTANCE.setStdOut(stdOut);
-            INSTANCE.setStdErr(stdErr);
-        } catch (Exception e) {
-            logger.log(Level.SEVERE, e.getMessage(), e);
-        }
     }
 
-    private final GhostscriptLibrary libraryInstance;
+    public synchronized static Ghostscript getInstance() {
-
+        if (INSTANCE == null) {
-    private Ghostscript() {
+            INSTANCE = createInstance();
-        libraryInstance = GhostscriptLibraryLoader.loadLibrary();
         }
-
-    public static Ghostscript getInstance() {
         return INSTANCE;
     }
 
@@ -65,7 +57,7 @@ public class Ghostscript {
      *
      * @return the Ghostscript revision data.
      */
-    public static GhostscriptRevision getRevision() {
+    public synchronized static GhostscriptRevision getRevision() {
         GhostscriptLibrary.gsapi_revision_s revision = new GhostscriptLibrary.gsapi_revision_s();
         INSTANCE.libraryInstance.gsapi_revision(revision, revision.size());
         GhostscriptRevision result = new GhostscriptRevision();
@@ -83,7 +75,7 @@ public class Ghostscript {
      *
      * @return The OutputStream or null
      */
-    public synchronized OutputStream getStdErr() {
+    public OutputStream getStdErr() {
         return stdErr;
     }
 
@@ -92,7 +84,7 @@ public class Ghostscript {
      *
      * @param outputStream OutputStream object
      */
-    public synchronized void setStdErr(OutputStream outputStream) {
+    public void setStdErr(OutputStream outputStream) {
         stdErr = outputStream;
     }
 
@@ -101,7 +93,7 @@ public class Ghostscript {
      *
      * @return The OutputStream or null
      */
-    public synchronized OutputStream getStdOut() {
+    public OutputStream getStdOut() {
         return stdOut;
     }
 
@@ -110,7 +102,7 @@ public class Ghostscript {
      *
      * @param outputStream OutputStream object
      */
-    public synchronized void setStdOut(OutputStream outputStream) {
+    public void setStdOut(OutputStream outputStream) {
         stdOut = outputStream;
     }
 
@@ -119,7 +111,7 @@ public class Ghostscript {
      *
      * @return The InputStream or null
      */
-    public synchronized InputStream getStdIn() {
+    public InputStream getStdIn() {
         return stdIn;
     }
 
@@ -128,7 +120,7 @@ public class Ghostscript {
      *
      * @param inputStream InputStream object
      */
-    public synchronized void setStdIn(InputStream inputStream) {
+    public void setStdIn(InputStream inputStream) {
         stdIn = inputStream;
     }
 
@@ -265,6 +257,35 @@ public class Ghostscript {
         }
     }
 
+    public synchronized void close() throws IOException {
+        if (stdIn != null) {
+            stdIn.close();
+            stdIn = null;
+        }
+        if (stdOut != null) {
+            stdOut.close();
+            stdOut = null;
+        }
+        if (stdErr != null) {
+            stdErr.close();
+            stdErr = null;
+        }
+        libraryInstance = null;
+        INSTANCE = null;
+        System.gc();
+        logger.log(Level.INFO, "ghostscript instance closed and gc'ed()");
+    }
+
+    private static Ghostscript createInstance() {
+        try {
+            prepareTmp();
+            return new Ghostscript(GhostscriptLibraryLoader.loadLibrary());
+        } catch (Exception e) {
+            logger.log(Level.SEVERE, e.getMessage(), e);
+        }
+        return null;
+    }
+
     private static void prepareTmp() throws IOException {
         String tmp = System.getenv("TMPDIR"); // the variable that ghostscript uses
         if (tmp == null) {

graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFConverter.java

@@ -106,9 +106,10 @@ public class PDFConverter {
         if (outputStream == null) {
             return;
         }
+        Ghostscript gs = Ghostscript.getInstance();
+        try {
             prepare(tmpPath);
             Path output = Files.createTempFile(tmpPath, "pdf", "pdf");
-        Ghostscript gs = Ghostscript.getInstance();
             List<String> gsArgs = new LinkedList<>();
             gsArgs.add("-ps2pdf");
             gsArgs.add("-dNOPAUSE");
@@ -174,6 +175,9 @@ public class PDFConverter {
             } finally {
                 delete(tmpPath);
             }
+        } finally {
+            gs.close();
+        }
     }
 
     private static void prepare(Path path) throws IOException {

graphics-ghostscript/src/main/java/org/xbib/graphics/ghostscript/PDFRasterizer.java

@@ -143,11 +143,15 @@ public class PDFRasterizer {
         logger.info("pdfToImage args=" + gsArgs);
         // reset stdin
         Ghostscript gs = Ghostscript.getInstance();
+        try {
             gs.setStdIn(null);
             gs.setStdOut(new LoggingOutputStream(logger));
             gs.setStdErr(new LoggingOutputStream(logger));
             gs.run(gsArgs.toArray(new String[gsArgs.size()]));
             logger.info("pdfToImage done");
+        } finally {
+            gs.close();
+        }
     }
 
     public synchronized void pdfToImage(Path sourceFile,
@@ -179,12 +183,16 @@ public class PDFRasterizer {
         gsArgs.add(sourceFile.toString());
         logger.info("pdfToImage args=" + gsArgs);
         Ghostscript gs = Ghostscript.getInstance();
+        try {
             // reset stdin
             gs.setStdIn(null);
             gs.setStdOut(new LoggingOutputStream(logger));
             gs.setStdErr(new LoggingOutputStream(logger));
             gs.run(gsArgs.toArray(new String[gsArgs.size()]));
             logger.info("pdfToImage done");
+        } finally {
+            gs.close();
+        }
     }
 
     public int mergeImagesToPDF(Path sourceDir, Path targetFile) throws IOException {
@@ -287,10 +295,14 @@ public class PDFRasterizer {
         gsArgs.add("-sOutputFile=" + targetFile.toString());
         gsArgs.add(sourceFile.toString());
         Ghostscript gs = Ghostscript.getInstance();
+        try {
             gs.setStdIn(null);
             logger.info(gsArgs.toString());
             gs.run(gsArgs.toArray(new String[gsArgs.size()]));
             logger.info("scalePDF: source = " + sourceFile + " target = " + targetFile + " done");
+        } finally {
+            gs.close();
+        }
     }
 
     public void toPDFA(Path source, Path target) throws IOException {
@@ -326,14 +338,15 @@ public class PDFRasterizer {
         gsArgs.add("-sOutputFile=" + target.toString());
         gsArgs.add(pdfapsPath.toAbsolutePath().toString());
         gsArgs.add(source.toString());
-        try {
         Ghostscript gs = Ghostscript.getInstance();
+        try {
             gs.setStdIn(null);
             gs.run(gsArgs.toArray(new String[gsArgs.size()]));
         } finally {
             delete(pdfapsPathTmp);
             delete(pdfapsPath);
             delete(iccPath);
+            gs.close();
         }
     }
 

graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostScriptLibraryTester.java

@@ -1,4 +1,4 @@
-package org.xbib.graphics.ghostscript;
+package org.xbib.graphics.ghostscript.test;
 
 import com.sun.jna.ptr.IntByReference;
 import org.xbib.graphics.ghostscript.internal.GhostscriptLibrary;

graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptLibraryTest.java

@@ -3,7 +3,6 @@ package org.xbib.graphics.ghostscript.test;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
-import org.xbib.graphics.ghostscript.GhostScriptLibraryTester;
 
 import java.io.File;
 import java.util.logging.Logger;

graphics-ghostscript/src/test/java/org/xbib/graphics/ghostscript/test/GhostscriptTest.java

@@ -1,5 +1,8 @@
 package org.xbib.graphics.ghostscript.test;
 
+import java.io.IOException;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.xbib.graphics.ghostscript.Ghostscript;
@@ -20,7 +23,17 @@ public class GhostscriptTest {
 
     private static final String dir = "src/test/resources/org/xbib/graphics/ghostscript/test/";
 
-    private static final Ghostscript gs = Ghostscript.getInstance();
+    static Ghostscript gs;
+
+    @BeforeAll
+    public static void init() {
+        gs = Ghostscript.getInstance();
+    }
+
+    @AfterAll
+    public static void shutdown() throws IOException {
+        gs.close();
+    }
 
     @Test
     public void testGetRevision() {