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package org.apache.xml.fop.fo;
// FOP
import org.apache.xml.fop.layout.AreaTree;
import org.apache.xml.fop.apps.FOPException;
import org.apache.xml.fop.fo.pagination.Root;
// SAX
import org.xml.sax.HandlerBase;
import org.xml.sax.SAXException;
import org.xml.sax.InputSource;
import org.xml.sax.AttributeList;
// Java
import java.util.Hashtable;
import java.util.Stack;
import java.io.IOException;
/**
* SAX Handler that builds the formatting object tree.
*/
public class FOTreeBuilder extends HandlerBase {
/**
* table mapping element names to the makers of objects
* representing formatting objects
*/
protected Hashtable fobjTable = new Hashtable();
/**
* class that builds a property list for each formatting object
*/
protected PropertyListBuilder propertyListBuilder = new
PropertyListBuilder();
/**
* current formatting object being handled
*/
protected FObj currentFObj = null;
/**
* the root of the formatting object tree
*/
protected FObj rootFObj = null;
/**
* set of names of formatting objects encountered but unknown
*/
protected Hashtable unknownFOs = new Hashtable();
// namespace implementation ideas pinched from John Cowan
protected static class NSMap {
String prefix;
String uri;
int level;
NSMap(String prefix, String uri, int level) {
this.prefix = prefix;
this.uri = uri;
this.level = level;
}
}
protected int level = 0;
protected Stack namespaceStack = new Stack();
{
namespaceStack.push(new NSMap("xml",
"http://www.w3.org/XML/1998/namespace",
-1));
namespaceStack.push(new NSMap("", "", -1));
}
protected String findURI(String prefix) {
for (int i = namespaceStack.size() - 1; i >= 0; i--) {
NSMap nsMap = (NSMap) (namespaceStack.elementAt(i));
if (prefix.equals(nsMap.prefix)) return nsMap.uri;
}
return null;
}
protected String mapName(String name)
throws SAXException {
int colon = name.indexOf(':');
String prefix = "";
String localPart = name;
if (colon != -1) {
prefix = name.substring(0, colon);
localPart = name.substring(colon + 1);
}
String uri = findURI(prefix);
if (uri == null) {
if (prefix.equals("")) {
return name;
} else {
throw new SAXException(new FOPException("Unknown namespace prefix " + prefix));
}
}
return uri + "^" + localPart;
}
/**
* add a mapping from element name to maker.
*
* @param namespaceURI namespace URI of formatting object element
* @param localName local name of formatting object element
* @param maker Maker for class representing formatting object
*/
public void addMapping(String namespaceURI, String localName,
FObj.Maker maker) {
this.fobjTable.put(namespaceURI + "^" + localName, maker);
}
/** SAX Handler for characters */
public void characters(char data[], int start, int length) {
currentFObj.addCharacters(data, start, start + length);
}
/** SAX Handler for the end of an element */
public void endElement(String name) {
currentFObj.end();
currentFObj = (FObj) currentFObj.getParent();
level--;
while (((NSMap) namespaceStack.peek()).level > level) {
namespaceStack.pop();
}
}
/** SAX Handler for the start of the document */
public void startDocument() {
System.err.println("building formatting object tree");
}
/** SAX Handler for the start of an element */
public void startElement(String name, AttributeList attlist)
throws SAXException {
/* the formatting object started */
FObj fobj;
/* the maker for the formatting object started */
FObj.Maker fobjMaker;
level++;
int length = attlist.getLength();
for (int i = 0; i < length; i++) {
String att = attlist.getName(i);
if (att.equals("xmlns")) {
namespaceStack.push( new NSMap("",
attlist.getValue(i),
level));
} else if (att.startsWith("xmlns:")) {
String value = attlist.getValue(i);
namespaceStack.push(new NSMap(att.substring(6), value,
level));
}
}
String fullName = mapName(name);
fobjMaker = (FObj.Maker) fobjTable.get(fullName);
if (fobjMaker == null) {
if (!this.unknownFOs.containsKey(fullName)) {
this.unknownFOs.put(fullName, "");
System.err.println("WARNING: Unknown formatting object "
+ fullName);
}
fobjMaker = new FObjMixed.Maker(); // fall back
}
try {
fobj =
fobjMaker.make(currentFObj,
this.propertyListBuilder.makeList(attlist,
(currentFObj == null) ? null : currentFObj.properties));
} catch (FOPException e) {
throw new SAXException(e);
}
if (rootFObj == null) {
rootFObj = fobj;
if (!fobj.getName().equals("fo:root")) {
throw new SAXException(new FOPException("Root element must"
+ " be root, not "
+ fobj.getName()));
}
} else {
currentFObj.addChild(fobj);
}
currentFObj = fobj;
}
/**
* format this formatting object tree
*
* @param areaTree the area tree to format into
*/
public void format(AreaTree areaTree)
throws FOPException {
System.err.println("formatting FOs into areas");
((Root) this.rootFObj).format(areaTree);
}
}
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