Merged SimpleStructureTree and ParsedStructureTree classes into a single one, used by both TransformerNodeEndProcessing and intermediate XML parsers

git-svn-id: https://svn.apache.org/repos/asf/xmlgraphics/fop/branches/Temp_Accessibility@825504 13f79535-47bb-0310-9956-ffa450edef68

10 files changed, 126 insertions, 155 deletions

diff --git a/src/java/org/apache/fop/accessibility/SimpleStructureTree.java b/src/java/org/apache/fop/accessibility/SimpleStructureTree.java
deleted file mode 100644
index c009b7b30..000000000
--- a/src/java/org/apache/fop/accessibility/SimpleStructureTree.java
+++ /dev/null
@@ -1,66 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements.  See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License.  You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-/* $Id$ */
-
-package org.apache.fop.accessibility;
-
-import java.io.StringWriter;
-import java.io.Writer;
-
-import javax.xml.transform.Transformer;
-import javax.xml.transform.TransformerFactory;
-import javax.xml.transform.dom.DOMSource;
-import javax.xml.transform.stream.StreamResult;
-
-import org.w3c.dom.Node;
-import org.w3c.dom.NodeList;
-
-/**
- * A StructureTree implementation created from the reduced FO tree, in the form
- * of a single DOM document obtained by XSL Transformation of the original FO
- * tree.
- */
-final class SimpleStructureTree implements StructureTree {
-
-    private final Node reducedFOTree;
-
-    SimpleStructureTree(Node reducedFOTree) {
-        this.reducedFOTree = reducedFOTree;
-    }
-
-    /** {@inheritDoc} */
-    public NodeList getPageSequence(int number) {
-        Node pageSequence = reducedFOTree.getFirstChild().getChildNodes().item(number - 1);
-        assert pageSequence.getNodeType() == Node.ELEMENT_NODE
-                && pageSequence.getLocalName().equals("page-sequence");
-        return pageSequence.getChildNodes();
-    }
-
-    /** {@inheritDoc} */
-    public String toString() {
-        try {
-            Transformer t = TransformerFactory.newInstance().newTransformer();
-            Writer str = new StringWriter();
-            t.transform(new DOMSource(reducedFOTree), new StreamResult(str));
-            return str.toString();
-        } catch (Exception e) {
-            return e.toString();
-        }
-    }
-
-}
diff --git a/src/java/org/apache/fop/accessibility/StructureTree.java b/src/java/org/apache/fop/accessibility/StructureTree.java
index 09a33f151..a0fdaac21 100644
--- a/src/java/org/apache/fop/accessibility/StructureTree.java
+++ b/src/java/org/apache/fop/accessibility/StructureTree.java
@@ -19,20 +19,84 @@
 
 package org.apache.fop.accessibility;
 
+import java.io.StringWriter;
+import java.io.Writer;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+
+import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
 /**
  * A reduced version of the document's FO tree, containing only its logical
  * structure. Used by accessible output formats.
  */
-public interface StructureTree {
+public final class StructureTree {
+
+    private final List pageSequenceStructures = new ArrayList();
+
+    /**
+     * Package-private default constructor.
+     */
+    StructureTree() { }
+
+    private static boolean flowOrStaticContentNodes(NodeList nodes) {
+        for (int i = 0; i < nodes.getLength(); i++) {
+            Node node = nodes.item(i);
+            if (node.getNodeType() != Node.ELEMENT_NODE) {
+                return false;
+            }
+            String name = node.getLocalName();
+            if (!(name.equals("flow") || name.equals("static-content"))) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    void addPageSequenceStructure(NodeList structureTree) {
+        assert flowOrStaticContentNodes(structureTree);
+        pageSequenceStructures.add(structureTree);
+    }
 
     /**
      * Returns the list of nodes that are the children of the given page sequence.
      *
-     * @param number number of the page sequence, 1-based
+     * @param index index of the page sequence, 0-based
      * @return its children nodes
      */
-    NodeList getPageSequence(int number);
+    public NodeList getPageSequence(int index) {
+        return (NodeList) pageSequenceStructures.get(index);
+    }
+
+    /**
+     * Returns an XML-like representation of the structure trees.
+     * <p>
+     * <strong>Note:</strong> use only for debugging purpose, as this method
+     * performs non-trivial operations.
+     * </p>
+     * @return a string representation of this object
+     */
+    public String toString() {
+        try {
+            Transformer t = TransformerFactory.newInstance().newTransformer();
+            Writer str = new StringWriter();
+            for (Iterator iter = pageSequenceStructures.iterator(); iter.hasNext();) {
+                NodeList nodes = (NodeList) iter.next();
+                for (int i = 0, c = nodes.getLength(); i < c; i++) {
+                    t.transform(new DOMSource(nodes.item(i)), new StreamResult(str));
+                }
+            }
+            return str.toString();
+        } catch (Exception e) {
+            return e.toString();
+        }
+    }
 
 }
diff --git a/src/java/org/apache/fop/accessibility/ParsedStructureTree.java b/src/java/org/apache/fop/accessibility/StructureTreeBuilder.java
index 646496252..cd9aa011a 100644
--- a/src/java/org/apache/fop/accessibility/ParsedStructureTree.java
+++ b/src/java/org/apache/fop/accessibility/StructureTreeBuilder.java
@@ -19,36 +19,25 @@
 
 package org.apache.fop.accessibility;
 
-import java.io.StringWriter;
-import java.io.Writer;
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.List;
-
-import javax.xml.transform.Transformer;
 import javax.xml.transform.TransformerConfigurationException;
-import javax.xml.transform.TransformerFactory;
 import javax.xml.transform.dom.DOMResult;
-import javax.xml.transform.dom.DOMSource;
 import javax.xml.transform.sax.SAXTransformerFactory;
 import javax.xml.transform.sax.TransformerHandler;
-import javax.xml.transform.stream.StreamResult;
 
-import org.w3c.dom.NodeList;
 import org.xml.sax.ContentHandler;
 import org.xml.sax.SAXException;
 
 import org.apache.fop.util.DelegatingContentHandler;
 
 /**
- * A StructureTree implementation re-created from the structure stored in an IF
- * XML document.
+ * Helper class that re-builds a structure tree from what is stored in an
+ * intermediate XML file (IF XML or Area Tree XML).
  */
-public class ParsedStructureTree implements StructureTree {
+public final class StructureTreeBuilder {
 
-    private SAXTransformerFactory factory;
+    private final SAXTransformerFactory factory;
 
-    private List pageSequenceStructures = new ArrayList();
+    private final StructureTree structureTree = new StructureTree();
 
     /**
      * Creates a new instance.
@@ -56,17 +45,25 @@ public class ParsedStructureTree implements StructureTree {
      * @param factory a factory internally used to build the structures of page
      * sequences
      */
-    public ParsedStructureTree(SAXTransformerFactory factory) {
+    public StructureTreeBuilder(SAXTransformerFactory factory) {
         this.factory = factory;
     }
 
     /**
+     * Returns the structure tree that will result from the parsing.
+     *
+     * @return the structure tree built by this object
+     */
+    public StructureTree getStructureTree() {
+        return structureTree;
+    }
+
+    /**
      * Returns a ContenHandler for parsing the structure of a new page sequence.
      * It is assumed that page sequences are being parsed in the document order.
-     * This class will automatically number the structure trees.
      *
-     * @return a handler for parsing the &lt;structure-tree&gt; element and its
-     * descendants
+     * @return a handler for parsing the &lt;structure-tree&gt; or
+     * &lt;structureTree&gt; element and its descendants
      * @throws SAXException if there is an error when creating the handler
      */
     public ContentHandler getHandlerForNextPageSequence() throws SAXException {
@@ -89,38 +86,10 @@ public class ParsedStructureTree implements StructureTree {
 
             public void endDocument() throws SAXException {
                 super.endDocument();
-                pageSequenceStructures.add(domResult.getNode().getFirstChild().getChildNodes());
+                structureTree.addPageSequenceStructure(domResult.getNode().getFirstChild()
+                        .getChildNodes());
             }
         };
     }
 
-    /** {@inheritDoc} */
-    public NodeList getPageSequence(int number) {
-        return (NodeList) pageSequenceStructures.get(number - 1);
-    }
-
-    /**
-     * Returns an XML-like representation of the structure trees.
-     * <p>
-     * <strong>Note:</strong> use only for debugging purpose, as this method
-     * performs non-trivial operations.
-     * </p>
-     * @return a string representation of this object
-     */
-    public String toString() {
-        try {
-            Transformer t = TransformerFactory.newInstance().newTransformer();
-            Writer str = new StringWriter();
-            for (Iterator iter = pageSequenceStructures.iterator(); iter.hasNext();) {
-                NodeList nodes = (NodeList) iter.next();
-                for (int i = 0, c = nodes.getLength(); i < c; i++) {
-                    t.transform(new DOMSource(nodes.item(i)), new StreamResult(str));
-                }
-            }
-            return str.toString();
-        } catch (Exception e) {
-            return e.toString();
-        }
-    }
-
 }
diff --git a/src/java/org/apache/fop/accessibility/TransformerNodeEndProcessing.java b/src/java/org/apache/fop/accessibility/TransformerNodeEndProcessing.java
index 00d4a5b56..36f36fdef 100644
--- a/src/java/org/apache/fop/accessibility/TransformerNodeEndProcessing.java
+++ b/src/java/org/apache/fop/accessibility/TransformerNodeEndProcessing.java
@@ -32,10 +32,12 @@ import javax.xml.transform.dom.DOMResult;
 import javax.xml.transform.stream.StreamResult;
 import javax.xml.transform.stream.StreamSource;
 
-import org.apache.commons.io.output.ByteArrayOutputStream;
+import org.w3c.dom.NodeList;
 import org.xml.sax.SAXException;
 import org.xml.sax.helpers.DefaultHandler;
 
+import org.apache.commons.io.output.ByteArrayOutputStream;
+
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.apps.FOUserAgent;
 
@@ -78,7 +80,12 @@ class TransformerNodeEndProcessing extends TransformerNode {
             Source src = new StreamSource(new ByteArrayInputStream(enrichedFO));
             DOMResult res = new DOMResult();
             transformer.transform(src, res);
-            userAgent.setStructureTree(new SimpleStructureTree(res.getNode()));
+            StructureTree structureTree = new StructureTree();
+            NodeList pageSequences = res.getNode().getFirstChild().getChildNodes();
+            for (int i = 0; i < pageSequences.getLength(); i++) {
+                structureTree.addPageSequenceStructure(pageSequences.item(i).getChildNodes());
+            }
+            userAgent.setStructureTree(structureTree);
 
             SAXParserFactory saxParserFactory = SAXParserFactory.newInstance();
             saxParserFactory.setNamespaceAware(true);
diff --git a/src/java/org/apache/fop/area/AreaTreeParser.java b/src/java/org/apache/fop/area/AreaTreeParser.java
index 12e31530d..784ca0684 100644
--- a/src/java/org/apache/fop/area/AreaTreeParser.java
+++ b/src/java/org/apache/fop/area/AreaTreeParser.java
@@ -57,7 +57,7 @@ import org.apache.xmlgraphics.image.loader.ImageManager;
 import org.apache.xmlgraphics.image.loader.ImageSessionContext;
 import org.apache.xmlgraphics.util.QName;
 
-import org.apache.fop.accessibility.ParsedStructureTree;
+import org.apache.fop.accessibility.StructureTreeBuilder;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.area.Trait.Background;
 import org.apache.fop.area.Trait.InternalLink;
@@ -160,17 +160,17 @@ public class AreaTreeParser {
         private Locator locator;
 
 
-        private ParsedStructureTree structureTree;
+        private StructureTreeBuilder structureTreeBuilder;
 
-        private ContentHandler structureTreeBuilder;
+        private ContentHandler structureTreeBuilderWrapper;
 
-        private final class StructureTreeBuilder extends DelegatingContentHandler {
+        private final class StructureTreeBuilderWrapper extends DelegatingContentHandler {
 
             private Attributes pageSequenceAttributes;
 
-            private StructureTreeBuilder(Attributes pageSequenceAttributes,
-                    ParsedStructureTree structureTree) throws SAXException {
-                super(structureTree.getHandlerForNextPageSequence());
+            private StructureTreeBuilderWrapper(Attributes pageSequenceAttributes)
+                    throws SAXException {
+                super(structureTreeBuilder.getHandlerForNextPageSequence());
                 this.pageSequenceAttributes = new AttributesImpl(pageSequenceAttributes);
             }
 
@@ -216,9 +216,10 @@ public class AreaTreeParser {
             makers.put("bookmarkTree", new BookmarkTreeMaker());
             makers.put("bookmark", new BookmarkMaker());
             makers.put("destination", new DestinationMaker());
+
             if (userAgent.isAccessibilityEnabled()) {
-                structureTree = new ParsedStructureTree(tFactory);
-                userAgent.setStructureTree(structureTree);
+                structureTreeBuilder = new StructureTreeBuilder(tFactory);
+                userAgent.setStructureTree(structureTreeBuilder.getStructureTree());
             }
         }
 
@@ -296,10 +297,10 @@ public class AreaTreeParser {
                 boolean handled = true;
                 if ("".equals(uri)) {
                     if (localName.equals("pageSequence") && userAgent.isAccessibilityEnabled()) {
-                        structureTreeBuilder = new StructureTreeBuilder(attributes, structureTree);
+                        structureTreeBuilderWrapper = new StructureTreeBuilderWrapper(attributes);
                     } else if (localName.equals("structureTree")) {
                         if (userAgent.isAccessibilityEnabled()) {
-                            delegate = structureTreeBuilder;
+                            delegate = structureTreeBuilderWrapper;
                         } else {
                             /* Delegate to a handler that does nothing */
                             delegate = new DefaultHandler();
diff --git a/src/java/org/apache/fop/render/intermediate/IFParser.java b/src/java/org/apache/fop/render/intermediate/IFParser.java
index 9ef65ce6f..e7bdd1b23 100644
--- a/src/java/org/apache/fop/render/intermediate/IFParser.java
+++ b/src/java/org/apache/fop/render/intermediate/IFParser.java
@@ -46,7 +46,7 @@ import org.apache.commons.logging.LogFactory;
 
 import org.apache.xmlgraphics.util.QName;
 
-import org.apache.fop.accessibility.ParsedStructureTree;
+import org.apache.fop.accessibility.StructureTreeBuilder;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.fo.ElementMapping;
 import org.apache.fop.fo.ElementMappingRegistry;
@@ -151,17 +151,17 @@ public class IFParser implements IFConstants {
 
         private ContentHandler navParser;
 
-        private ParsedStructureTree structureTree;
+        private StructureTreeBuilder structureTreeBuilder;
 
-        private ContentHandler structureTreeBuilder;
+        private ContentHandler structureTreeBuilderWrapper;
 
-        private final class StructureTreeBuilder extends DelegatingContentHandler {
+        private final class StructureTreeBuilderWrapper extends DelegatingContentHandler {
 
             private Attributes pageSequenceAttributes;
 
-            private StructureTreeBuilder(Attributes pageSequenceAttributes,
-                    ParsedStructureTree structureTree) throws SAXException {
-                super(structureTree.getHandlerForNextPageSequence());
+            private StructureTreeBuilderWrapper(Attributes pageSequenceAttributes)
+                    throws SAXException {
+                super(structureTreeBuilder.getHandlerForNextPageSequence());
                 this.pageSequenceAttributes = new AttributesImpl(pageSequenceAttributes);
             }
 
@@ -196,8 +196,8 @@ public class IFParser implements IFConstants {
             elementHandlers.put(EL_IMAGE, new ImageHandler());
 
             if (userAgent.isAccessibilityEnabled()) {
-                structureTree = new ParsedStructureTree(tFactory);
-                userAgent.setStructureTree(structureTree);
+                structureTreeBuilder = new StructureTreeBuilder(tFactory);
+                userAgent.setStructureTree(structureTreeBuilder.getStructureTree());
             }
         }
 
@@ -227,10 +227,10 @@ public class IFParser implements IFConstants {
                 boolean handled = true;
                 if (NAMESPACE.equals(uri)) {
                     if (localName.equals(EL_PAGE_SEQUENCE) && userAgent.isAccessibilityEnabled()) {
-                        structureTreeBuilder = new StructureTreeBuilder(attributes, structureTree);
+                        structureTreeBuilderWrapper = new StructureTreeBuilderWrapper(attributes);
                     } else if (localName.equals(EL_STRUCTURE_TREE)) {
                         if (userAgent.isAccessibilityEnabled()) {
-                            delegate = structureTreeBuilder;
+                            delegate = structureTreeBuilderWrapper;
                         } else {
                             /* Delegate to a handler that does nothing */
                             delegate = new DefaultHandler();
diff --git a/src/java/org/apache/fop/render/intermediate/IFSerializer.java b/src/java/org/apache/fop/render/intermediate/IFSerializer.java
index 9d7c15a61..b6136f036 100644
--- a/src/java/org/apache/fop/render/intermediate/IFSerializer.java
+++ b/src/java/org/apache/fop/render/intermediate/IFSerializer.java
@@ -63,7 +63,7 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
         implements IFConstants, IFPainter, IFDocumentNavigationHandler {
 
     private IFDocumentHandler mimicHandler;
-    private int pageSequenceCounter; // used for accessibility
+    private int pageSequenceIndex; // used for accessibility
 
     /** Holds the intermediate format state */
     private IFState state;
@@ -224,7 +224,7 @@ public class IFSerializer extends AbstractXMLWritingIFDocumentHandler
             if (this.getUserAgent().isAccessibilityEnabled()) {
                 StructureTree structureTree = getUserAgent().getStructureTree();
                 handler.startElement(EL_STRUCTURE_TREE); // add structure tree
-                NodeList nodes = structureTree.getPageSequence(++pageSequenceCounter);
+                NodeList nodes = structureTree.getPageSequence(pageSequenceIndex++);
                 for (int i = 0, n = nodes.getLength(); i < n; i++) {
                     Node node = nodes.item(i);
                     new DOM2SAX(handler).writeFragment(node);
diff --git a/src/java/org/apache/fop/render/pdf/PDFDocumentHandler.java b/src/java/org/apache/fop/render/pdf/PDFDocumentHandler.java
index b9d726bf2..3cd601bfa 100644
--- a/src/java/org/apache/fop/render/pdf/PDFDocumentHandler.java
+++ b/src/java/org/apache/fop/render/pdf/PDFDocumentHandler.java
@@ -62,7 +62,7 @@ public class PDFDocumentHandler extends AbstractBinaryWritingIFDocumentHandler {
     /** logging instance */
     private static Log log = LogFactory.getLog(PDFDocumentHandler.class);
 
-    private int pageSequenceNumber;
+    private int pageSequenceIndex;
 
     private boolean accessEnabled;
 
@@ -186,8 +186,7 @@ public class PDFDocumentHandler extends AbstractBinaryWritingIFDocumentHandler {
         }
 
         if (accessEnabled) {
-            NodeList nodes = getUserAgent().getStructureTree().getPageSequence(
-                    ++pageSequenceNumber);
+            NodeList nodes = getUserAgent().getStructureTree().getPageSequence(pageSequenceIndex++);
             logicalStructureHandler.processStructureTree(nodes, getContext().getLanguage());
         }
     }
diff --git a/src/java/org/apache/fop/render/pdf/PDFRenderer.java b/src/java/org/apache/fop/render/pdf/PDFRenderer.java
index 17ab1755c..380241ba0 100644
--- a/src/java/org/apache/fop/render/pdf/PDFRenderer.java
+++ b/src/java/org/apache/fop/render/pdf/PDFRenderer.java
@@ -204,7 +204,7 @@ public class PDFRenderer extends AbstractPathOrientedRenderer implements PDFConf
 
     private PDFLogicalStructureHandler logicalStructureHandler;
 
-    private int pageSequenceNumber;
+    private int pageSequenceIndex;
 
     /** Reference in the structure tree to the image being rendered. */
     private String imageReference;
@@ -428,8 +428,7 @@ public class PDFRenderer extends AbstractPathOrientedRenderer implements PDFConf
         }
         pdfUtil.generateDefaultXMPMetadata();
         if (accessEnabled) {
-            NodeList nodes = getUserAgent().getStructureTree().getPageSequence(
-                    ++pageSequenceNumber);
+            NodeList nodes = getUserAgent().getStructureTree().getPageSequence(pageSequenceIndex++);
             logicalStructureHandler.processStructureTree(nodes, language);
         }
     }
diff --git a/src/java/org/apache/fop/render/xml/XMLRenderer.java b/src/java/org/apache/fop/render/xml/XMLRenderer.java
index d86814d25..a8a1a1911 100644
--- a/src/java/org/apache/fop/render/xml/XMLRenderer.java
+++ b/src/java/org/apache/fop/render/xml/XMLRenderer.java
@@ -41,7 +41,6 @@ import org.xml.sax.SAXException;
 import org.apache.xmlgraphics.util.QName;
 import org.apache.xmlgraphics.util.XMLizable;
 
-import org.apache.fop.accessibility.StructureTree;
 import org.apache.fop.apps.FOPException;
 import org.apache.fop.apps.FOUserAgent;
 import org.apache.fop.apps.MimeConstants;
@@ -108,7 +107,7 @@ public class XMLRenderer extends AbstractXMLRenderer {
     /** If not null, the XMLRenderer will mimic another renderer by using its font setup. */
     protected Renderer mimic;
 
-    private int pageSequenceNumber;
+    private int pageSequenceIndex;
 
     /**
      * Creates a new XML renderer.
@@ -446,10 +445,9 @@ public class XMLRenderer extends AbstractXMLRenderer {
         transferForeignObjects(pageSequence);
         startElement("pageSequence", atts);
         if (this.getUserAgent().isAccessibilityEnabled()) {
-            StructureTree structureTree = getUserAgent().getStructureTree();
             String structureTreeElement = "structureTree";
             startElement(structureTreeElement);
-            NodeList nodes = structureTree.getPageSequence(++pageSequenceNumber);
+            NodeList nodes = getUserAgent().getStructureTree().getPageSequence(pageSequenceIndex++);
             for (int i = 0, n = nodes.getLength(); i < n; i++) {
                 Node node = nodes.item(i);
                 try {