Fix duplicate listener problem.

We were adding the default listener in CompressorDecompressorBase, which
resulted in both ImageCompressor and specialized (SQ|VQ)ImageCompressor
having this listener. Then in getImage(Compressor|Decompressor) we
duplicated all listener from base class. This resulted in having two
same listeners, with different lamda adresses.

src/main/java/azgracompress/compression/CompressorDecompressorBase.java

@@ -24,16 +24,19 @@ public abstract class CompressorDecompressorBase {
     public CompressorDecompressorBase(CompressionOptions options) {
         this.options = options;
         this.codebookSize = (int) Math.pow(2, this.options.getBitsPerCodebookIndex());
-        // Default status listener, which can be override by setStatusListener.
-
-        if (options.isVerbose())
-            addStatusListener(this::defaultLog);
     }
 
     public void addStatusListener(final IStatusListener listener) {
         if (statusListeners == null) {
             statusListeners = new ArrayList<>(1);
         }
+        if (statusListeners.size() > 0) {
+            System.out.println("Existing listeners:");
+            for (final IStatusListener l : statusListeners)
+                System.out.println("\t" + l);
+        }
+        System.out.println(this + " - Adding new statusListener: " + listener);
+
         statusListeners.add(listener);
     }
 
@@ -129,7 +132,7 @@ public abstract class CompressorDecompressorBase {
     }
 
 
-    private void defaultLog(final String message) {
+    public void defaultLog(final String message) {
         if (options.isVerbose()) {
             System.out.println(message);
         }

src/main/java/azgracompress/compression/ImageCompressor.java

@@ -36,6 +36,10 @@ public class ImageCompressor extends CompressorDecompressorBase {
 
         // Forward listeners to image compressor.
         duplicateAllListeners(compressor);
+
+        if (options.isVerbose())
+            compressor.addStatusListener(this::defaultLog);
+
         return compressor;
     }
 

src/main/java/azgracompress/compression/ImageDecompressor.java

@@ -55,6 +55,10 @@ public class ImageDecompressor extends CompressorDecompressorBase {
 
         // Forward listeners to image decompressor.
         duplicateAllListeners(decompressor);
+
+        if(options.isVerbose())
+            decompressor.addStatusListener(this::defaultLog);
+
         return decompressor;
     }