/*
* 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 embedding.events;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URL;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.stream.StreamSource;
import org.xml.sax.SAXException;
import org.apache.commons.io.IOUtils;
import org.apache.fop.apps.FOPException;
import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.apps.Fop;
import org.apache.fop.apps.FopFactory;
import org.apache.fop.apps.MimeConstants;
import org.apache.fop.events.Event;
import org.apache.fop.events.EventFormatter;
import org.apache.fop.events.EventListener;
import org.apache.fop.events.model.EventSeverity;
/**
* This class demonstrates how to register an event listener with FOP so you can customize
* FOP's error behaviour.
*/
public class ExampleEvents {
// configure fopFactory as desired
private final FopFactory fopFactory = FopFactory.newInstance(new File(".").toURI());
/**
* Converts an FO file to a PDF file using FOP
* @param fo the FO file
* @param pdf the target PDF file
* @throws IOException In case of an I/O problem
* @throws FOPException In case of a FOP problem
* @throws TransformerException In case of a problem with XSLT
*/
public void convertFO2PDF(URL fo, File pdf)
throws IOException, FOPException, TransformerException {
OutputStream out = null;
try {
//Create the user agent for this processing run
FOUserAgent foUserAgent = fopFactory.newFOUserAgent();
//Adding a simple logging listener that writes to stdout and stderr
foUserAgent.getEventBroadcaster().addEventListener(new SysOutEventListener());
// Add your own event listener
foUserAgent.getEventBroadcaster().addEventListener(new MyEventListener());
// configure foUserAgent further as desired
// Setup output stream. Note: Using BufferedOutputStream
// for performance reasons (helpful with FileOutputStreams).
out = new FileOutputStream(pdf);
out = new BufferedOutputStream(out);
// Construct fop with desired output format
Fop fop = fopFactory.newFop(MimeConstants.MIME_PDF, foUserAgent, out);
// Setup JAXP using identity transformer
TransformerFactory factory = TransformerFactory.newInstance();
Transformer transformer = factory.newTransformer(); // identity transformer
// Setup input stream
Source src = new StreamSource(fo.toExternalForm());
// Resulting SAX events (the generated FO) must be piped through to FOP
Result res = new SAXResult(fop.getDefaultHandler());
// Start XSLT transformation and FOP processing
transformer.transform(src, res);
} finally {
IOUtils.closeQuietly(out);
}
}
private static class MyEventListener implements EventListener {
public void processEvent(Event event) {
if ("org.apache.fop.ResourceEventProducer.imageNotFound"
.equals(event.getEventID())) {
//Get the FileNotFoundException that's part of the event's parameters
FileNotFoundException fnfe = (FileNotFoundException)event.getParam("fnfe");
System.out.println("---=== imageNotFound Event for " + event.getParam("uri")
+ "!!! ===---");
//Stop processing when an image could not be found. Otherwise, FOP would just
//continue without the image!
System.out.println("Throwing a RuntimeException...");
throw new RuntimeException(EventFormatter.format(event), fnfe);
} else {
//ignore all other events
}
}
}
/** A simple event listener that writes the events to stdout and sterr. */
private static class SysOutEventListener implements EventListener {
/** {@inheritDoc} */
public void processEvent(Event event) {
String msg = EventFormatter.format(event);
EventSeverity severity = event.getSeverity();
if (severity == EventSeverity.INFO) {
System.out.println("[INFO ] " + msg);
} else if (severity == EventSeverity.WARN) {
System.out.println("[WARN ] " + msg);
} else if (severity == EventSeverity.ERROR) {
System.err.println("[ERROR] " + msg);
} else if (severity == EventSeverity.FATAL) {
System.err.println("[FATAL] " + msg);
} else {
assert false;
}
}
}
/**
* This method extracts the original exception from some exception. The exception
* might be nested multiple levels deep.
* @param t the Throwable to inspect
* @return the original Throwable or the method parameter t if there are no nested Throwables.
*/
private static Throwable getOriginalThrowable(Throwable t) {
if (t instanceof SAXException) {
SAXException saxe = (SAXException)t;
if (saxe.getException() != null) {
return getOriginalThrowable(saxe.getException());
} else {
return saxe;
}
} else {
if (t.getCause() != null) {
return getOriginalThrowable(t.getCause());
} else {
return t;
}
}
}
/**
* Main method.
* @param args command-line arguments
*/
public static void main(String[] args) {
try {
System.out.println("FOP ExampleEvents\n");
System.out.println("Preparing...");
//Setup directories
File baseDir = new File(".");
File outDir = new File(baseDir, "out");
outDir.mkdirs();
//Setup input and output files
URL fo = ExampleEvents.class.getResource("missing-image.fo");
File pdffile = new File(outDir, "out.pdf");
System.out.println("Input: XSL-FO (" + fo.toExternalForm() + ")");
System.out.println("Output: PDF (" + pdffile + ")");
System.out.println();
System.out.println("Transforming...");
ExampleEvents app = new ExampleEvents();
try {
app.convertFO2PDF(fo, pdffile);
} catch (TransformerException te) {
//Note: We don't get the original exception here!
//FOP needs to embed the exception in a SAXException and the TraX transformer
//again wraps the SAXException in a TransformerException. Even our own
//RuntimeException just wraps the original FileNotFoundException.
//So we need to unpack to get the original exception (about three layers deep).
Throwable originalThrowable = getOriginalThrowable(te);
originalThrowable.printStackTrace(System.err);
System.out.println("Aborted!");
System.exit(-1);
}
System.out.println("Success!");
} catch (Exception e) {
//Some other error (shouldn't happen in this example)
e.printStackTrace(System.err);
System.exit(-1);
}
}
}