Simplified the setting of filters in the AbstractPDFStream hierarchy. Instead of unnecessarily re-defining the setupFilterList method, sub-classes just define a getDefaultFilterName method

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/trunk@757712 13f79535-47bb-0310-9956-ffa450edef68

src/java/org/apache/fop/pdf/AbstractPDFFontStream.java

@@ -33,9 +33,8 @@ public abstract class AbstractPDFFontStream extends AbstractPDFStream {
     }
 
     /** {@inheritDoc} */
-    protected void setupFilterList() {
-        addDefaultFilter(PDFFilterList.FONT_FILTER);
-        super.setupFilterList();
+    protected String getDefaultFilterName() {
+        return PDFFilterList.FONT_FILTER;
     }
 
 }

src/java/org/apache/fop/pdf/AbstractPDFStream.java

@@ -47,21 +47,23 @@ public abstract class AbstractPDFStream extends PDFDictionary {
      * from outside.
      */
     protected void setupFilterList() {
-        addDefaultFilter(PDFFilterList.DEFAULT_FILTER);
+        if (!getFilterList().isInitialized()) {
+            getFilterList().addDefaultFilters(
+                getDocumentSafely().getFilterMap(),
+                getDefaultFilterName());
+        }
         prepareImplicitFilters();
         getDocument().applyEncryption(this);
     }
 
     /**
-     * Adds the default filter to the filter list if the filter list hasn't been initialized, yet.
-     * @param filterName the name of the default filter to use
+     * Returns the name of a suitable filter for this PDF object.
+     *
+     * @return the default filter
+     * @see PDFFilterList
      */
-    protected void addDefaultFilter(String filterName) {
-        if (!getFilterList().isInitialized()) {
-            getFilterList().addDefaultFilters(
-                getDocumentSafely().getFilterMap(),
-                filterName);
-        }
+    protected String getDefaultFilterName() {
+        return PDFFilterList.DEFAULT_FILTER;
     }
 
     /**

src/java/org/apache/fop/pdf/PDFImageXObject.java

@@ -159,14 +159,11 @@ public class PDFImageXObject extends PDFXObject {
     }
 
     /**
-     * This sets up the default filters for XObjects. It uses the PDFImage
-     * instance to determine what default filters to apply.
      * {@inheritDoc}
+     * This class uses the PDFImage instance to determine the default filter.
      */
-    protected void setupFilterList() {
-        addDefaultFilter(pdfimage.getFilterHint());
-        super.setupFilterList();
+    protected String getDefaultFilterName() {
+        return pdfimage.getFilterHint();
     }
 
-
 }

src/java/org/apache/fop/pdf/PDFMetadata.java

@@ -59,9 +59,8 @@ public class PDFMetadata extends PDFStream {
     }
 
     /** {@inheritDoc} */
-    protected void setupFilterList() {
-        addDefaultFilter(PDFFilterList.METADATA_FILTER);
-        super.setupFilterList();
+    protected String getDefaultFilterName() {
+        return PDFFilterList.METADATA_FILTER;
     }
 
     /**