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/*
* 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 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 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 index index of the page sequence, 0-based
* @return its children nodes
*/
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();
}
}
}
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