org.apache.fop.events.model.EventModelParser Maven / Gradle / Ivy
/*
* 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: EventModelParser.java 985571 2010-08-14 19:28:26Z jeremias $ */
package org.apache.fop.events.model;
import java.util.Stack;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXTransformerFactory;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.fop.util.DefaultErrorListener;
/**
* This is a parser for the event model XML.
*/
public final class EventModelParser {
private EventModelParser() {
}
/** Logger instance */
private static final Log LOG = LogFactory.getLog(EventModelParser.class);
private static SAXTransformerFactory tFactory
= (SAXTransformerFactory)SAXTransformerFactory.newInstance();
/**
* Parses an event model file into an EventModel instance.
* @param src the Source instance pointing to the XML file
* @return the created event model structure
* @throws TransformerException if an error occurs while parsing the XML file
*/
public static EventModel parse(Source src)
throws TransformerException {
Transformer transformer = tFactory.newTransformer();
transformer.setErrorListener(new DefaultErrorListener(LOG));
EventModel model = new EventModel();
SAXResult res = new SAXResult(getContentHandler(model));
transformer.transform(src, res);
return model;
}
/**
* Creates a new ContentHandler instance that you can send the event model XML to. The parsed
* content is accumulated in the model structure.
* @param model the EventModel
* @return the ContentHandler instance to receive the SAX stream from the XML file
*/
public static ContentHandler getContentHandler(EventModel model) {
return new Handler(model);
}
private static class Handler extends DefaultHandler {
private EventModel model;
private Stack objectStack = new Stack();
public Handler(EventModel model) {
this.model = model;
}
/** {@inheritDoc} */
public void startElement(String uri, String localName, String qName, Attributes attributes)
throws SAXException {
try {
if ("event-model".equals(localName)) {
if (objectStack.size() > 0) {
throw new SAXException("event-model must be the root element");
}
objectStack.push(model);
} else if ("producer".equals(localName)) {
EventProducerModel producer = new EventProducerModel(
attributes.getValue("name"));
EventModel parent = (EventModel)objectStack.peek();
parent.addProducer(producer);
objectStack.push(producer);
} else if ("method".equals(localName)) {
EventSeverity severity = EventSeverity.valueOf(attributes.getValue("severity"));
String ex = attributes.getValue("exception");
EventMethodModel method = new EventMethodModel(
attributes.getValue("name"), severity);
if (ex != null && ex.length() > 0) {
method.setExceptionClass(ex);
}
EventProducerModel parent = (EventProducerModel)objectStack.peek();
parent.addMethod(method);
objectStack.push(method);
} else if ("parameter".equals(localName)) {
String className = attributes.getValue("type");
Class type;
try {
type = Class.forName(className);
} catch (ClassNotFoundException e) {
throw new SAXException("Could not find Class for: " + className, e);
}
String name = attributes.getValue("name");
EventMethodModel parent = (EventMethodModel)objectStack.peek();
objectStack.push(parent.addParameter(type, name));
} else {
throw new SAXException("Invalid element: " + qName);
}
} catch (ClassCastException cce) {
throw new SAXException("XML format error: " + qName, cce);
}
}
/** {@inheritDoc} */
public void endElement(String uri, String localName, String qName) throws SAXException {
objectStack.pop();
}
}
}