/*
* 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.render.intermediate;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
import org.xml.sax.helpers.DefaultHandler;
import org.apache.fop.accessibility.StructureTree2SAXEventAdapter;
import org.apache.fop.accessibility.StructureTreeElement;
import org.apache.fop.accessibility.StructureTreeEventHandler;
import org.apache.fop.fo.extensions.InternalElementMapping;
import org.apache.fop.util.XMLConstants;
import org.apache.fop.util.XMLUtil;
/**
* Saves structure tree events as SAX events in order to replay them when it's
* time to stream the structure tree to the output.
*/
final class IFStructureTreeBuilder implements StructureTreeEventHandler {
static final class IFStructureTreeElement implements StructureTreeElement {
private final String id;
IFStructureTreeElement() {
this.id = null;
}
IFStructureTreeElement(String id) {
this.id = id;
}
public String getId() {
return id;
}
}
/** A SAX handler that records events to replay them later. */
static class SAXEventRecorder extends DefaultHandler {
private final List<SAXEventRecorder.Event> events = new ArrayList<SAXEventRecorder.Event>();
private abstract static class Event {
abstract void replay(ContentHandler handler) throws SAXException;
}
private abstract static class Element extends SAXEventRecorder.Event {
protected final String uri;
protected final String localName;
protected final String qName;
private Element(String uri, String localName, String qName) {
this.uri = uri;
this.localName = localName;
this.qName = qName;
}
}
private static final class StartElement extends SAXEventRecorder.Element {
private final Attributes attributes;
private StartElement(String uri, String localName, String qName,
Attributes attributes) {
super(uri, localName, qName);
this.attributes = attributes;
}
@Override
void replay(ContentHandler handler) throws SAXException {
handler.startElement(uri, localName, qName, attributes);
}
}
private static final class EndElement extends SAXEventRecorder.Element {
private EndElement(String uri, String localName, String qName) {
super(uri, localName, qName);
}
@Override
void replay(ContentHandler handler) throws SAXException {
handler.endElement(uri, localName, qName);
}
}
private static final class StartPrefixMapping extends SAXEventRecorder.Event {
private final String prefix;
private final String uri;
private StartPrefixMapping(String prefix, String uri) {
this.prefix = prefix;
this.uri = uri;
}
@Override
void replay(ContentHandler handler) throws SAXException {
handler.startPrefixMapping(prefix, uri);
}
}
private static final class EndPrefixMapping extends SAXEventRecorder.Event {
private final String prefix;
private EndPrefixMapping(String prefix) {
this.prefix = prefix;
}
@Override
void replay(ContentHandler handler) throws SAXException {
handler.endPrefixMapping(prefix);
}
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
events.add(new StartElement(uri, localName, qName, attributes));
}
@Override
public void endElement(String uri, String localName, String qName) throws SAXException {
events.add(new EndElement(uri, localName, qName));
}
@Override
public void startPrefixMapping(String prefix, String uri) throws SAXException {
events.add(new StartPrefixMapping(prefix, uri));
}
@Override
public void endPrefixMapping(String prefix) throws SAXException {
events.add(new EndPrefixMapping(prefix));
}
/**
* Replays the recorded events.
*
* @param handler {@code ContentHandler} to replay events on
*/
public void replay(ContentHandler handler) throws SAXException {
for (SAXEventRecorder.Event e : events) {
e.replay(handler);
}
}
}
private StructureTreeEventHandler delegate;
private final List<SAXEventRecorder> pageSequenceEventRecorders
= new ArrayList<SAXEventRecorder>();
private SAXEventRecorder retrievedMarkersEventRecorder;
private int idCounter;
/**
* Replay SAX events for a page sequence.
* @param handler The handler that receives SAX events
* @param pageSequenceIndex The index of the page sequence
* @throws SAXException
*/
public void replayEventsForPageSequence(ContentHandler handler,
int pageSequenceIndex) throws SAXException {
pageSequenceEventRecorders.get(pageSequenceIndex).replay(handler);
}
public void replayEventsForRetrievedMarkers(ContentHandler handler) throws SAXException {
if (!retrievedMarkersEventRecorder.events.isEmpty()) {
delegate = StructureTree2SAXEventAdapter.newInstance(handler);
delegate.startPageSequence(null, null);
retrievedMarkersEventRecorder.replay(handler);
delegate.endPageSequence();
prepareRetrievedMarkersEventRecorder();
}
}
public void startPageSequence(Locale locale, String role) {
SAXEventRecorder eventRecorder = new SAXEventRecorder();
pageSequenceEventRecorders.add(eventRecorder);
delegate = StructureTree2SAXEventAdapter.newInstance(eventRecorder);
delegate.startPageSequence(locale, role);
}
public void endPageSequence() {
delegate.endPageSequence();
prepareRetrievedMarkersEventRecorder();
}
private void prepareRetrievedMarkersEventRecorder() {
SAXEventRecorder eventRecorder = new SAXEventRecorder();
retrievedMarkersEventRecorder = eventRecorder;
delegate = StructureTree2SAXEventAdapter.newInstance(eventRecorder);
}
public StructureTreeElement startNode(String name, Attributes attributes, StructureTreeElement parent) {
if (parent != null) {
attributes = addParentAttribute(new AttributesImpl(attributes), parent);
}
delegate.startNode(name, attributes, null);
return new IFStructureTreeElement();
}
private AttributesImpl addParentAttribute(AttributesImpl attributes, StructureTreeElement parent) {
if (parent != null) {
attributes.addAttribute(InternalElementMapping.URI,
InternalElementMapping.STRUCT_REF,
InternalElementMapping.STANDARD_PREFIX + ":" + InternalElementMapping.STRUCT_REF,
XMLConstants.CDATA,
((IFStructureTreeElement) parent).getId());
}
return attributes;
}
public void endNode(String name) {
delegate.endNode(name);
}
public StructureTreeElement startImageNode(String name, Attributes attributes, StructureTreeElement parent) {
String id = getNextID();
AttributesImpl atts = addIDAttribute(attributes, id);
addParentAttribute(atts, parent);
delegate.startImageNode(name, atts, null);
return new IFStructureTreeElement(id);
}
public StructureTreeElement startReferencedNode(String name, Attributes attributes, StructureTreeElement parent) {
String id = getNextID();
AttributesImpl atts = addIDAttribute(attributes, id);
addParentAttribute(atts, parent);
delegate.startReferencedNode(name, atts, null);
return new IFStructureTreeElement(id);
}
private String getNextID() {
return Integer.toHexString(idCounter++);
}
private AttributesImpl addIDAttribute(Attributes attributes, String id) {
AttributesImpl atts = new AttributesImpl(attributes);
atts.addAttribute(InternalElementMapping.URI,
InternalElementMapping.STRUCT_ID,
InternalElementMapping.STANDARD_PREFIX + ":" + InternalElementMapping.STRUCT_ID,
XMLUtil.CDATA,
id);
return atts;
}
}