/*
* 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.
*/
package org.apache.cocoon.components.source;
import org.apache.avalon.framework.component.ComponentException;
import org.apache.avalon.framework.component.ComponentManager;
import org.apache.avalon.framework.component.ComponentSelector;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.serialization.Serializer;
import org.apache.cocoon.xml.AbstractXMLPipe;
import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;
import java.io.IOException;
import java.io.OutputStream;
/**
* This abstract class provides convenience methods to implement
* a stream based <code>org.apache.cocoon.environment.WriteableSource</code>.
* Implement getOutputStream() to obtain a valid implementation.
* <p>
* This base implementation creates a <code>ContentHandler</code> by using
* the sitemap 'xml' serializer to write SAX events to the stream returned by
* <code>getOutputStream()</code>.
*
* @deprecated Use the new Avalon Excalibur Source Resolving
* @author <a href="mailto:sylvain@apache.org">Sylvain Wallez</a>
* @version CVS $Id$
*/
public abstract class AbstractStreamWriteableSource
extends AbstractStreamSource
implements org.apache.cocoon.environment.WriteableSource {
protected AbstractStreamWriteableSource(ComponentManager manager) {
super(manager);
}
/**
* Checks if the <code>OutputStream</code> under <code>handler</code> can be cancelled.
*
* @see #canCancel(OutputStream)
*/
public boolean canCancel(ContentHandler handler) {
if (handler instanceof WritingPipe) {
WritingPipe pipe = (WritingPipe)handler;
if (pipe.getSource() == this) {
return pipe.canCancel();
}
}
// Not a valid handler for this source
throw new IllegalArgumentException("The handler is not associated to this source");
}
/**
* Always return <code>false</code>. To be redefined by implementations that support
* <code>cancel()</code>.
*/
public boolean canCancel(OutputStream stream) {
return false;
}
/**
* Cancels the <code>OutputStream</code> under <code>handler</code>.
*
* @see #cancel(OutputStream)
*/
public void cancel(ContentHandler handler) throws Exception {
if (handler instanceof WritingPipe) {
WritingPipe pipe = (WritingPipe)handler;
if (pipe.getSource() == this) {
pipe.cancel();
return;
}
}
// Not a valid handler for this source
throw new IllegalArgumentException("The handler is not associated to this source");
}
/**
* Always throw <code>UnsupportedOperationException</code>. To be redefined by
* implementations that support <code>cancel()</code>.
*/
public void cancel(OutputStream stream) throws Exception {
throw new UnsupportedOperationException("Cancel is not implemented on " +
this.getClass().getName());
}
/**
* Get a <code>ContentHandler</code> to write a SAX stream to this source. It
* uses either the 'xml' or 'html' serializer depending on the result of
* {@link #isHTMLContent()} to serialize events, and thus these serializers must
* exist in this source's component manager.
*/
public ContentHandler getContentHandler() throws SAXException, ProcessingException {
Serializer serializer;
ComponentSelector selector;
String serializerName = this.isHTMLContent() ? "html" : "xml";
// Get the serializer
try {
selector =
(ComponentSelector)this.manager.lookup(Serializer.ROLE + "Selector");
serializer = (Serializer)selector.select(serializerName);
} catch(ComponentException ce) {
throw new ProcessingException("Cannot get '" + serializerName + "' serializer");
}
try {
return new WritingPipe(getOutputStream(), selector, serializer);
} catch(IOException ioe) {
selector.release(serializer);
throw new ProcessingException("Cannot open stream for " + this.getSystemId(), ioe);
}
}
/**
* A pipe that closes the outputstream at the end of the document and handles cancel().
*/
private class WritingPipe extends AbstractXMLPipe {
// The output stream
private OutputStream output;
// Serialier and its selector for proper release
private Serializer serializer;
private ComponentSelector selector;
public WritingPipe(OutputStream output, ComponentSelector selector, Serializer serializer)
throws IOException {
this.output = output;
this.selector = selector;
this.serializer = serializer;
// Connect this pipe, the serializer and the output stream
this.setConsumer(this.serializer);
this.serializer.setOutputStream(this.output);
}
public org.apache.cocoon.environment.WriteableSource getSource() {
return AbstractStreamWriteableSource.this;
}
/**
* Close the underlying stream
*/
public void endDocument() throws SAXException {
super.endDocument();
try {
close();
}
catch(Exception e) {
throw new SAXException("Error while closing output stream", e);
}
}
public boolean canCancel() {
return this.output != null;
}
/**
* Cancel the wrapped output stream
*/
public void cancel() throws Exception {
AbstractStreamWriteableSource.this.cancel(output);
close();
}
private void close() throws IOException {
if (this.serializer != null) {
// Disconnect serializer;
this.recycle();
// and release it
this.selector.release(this.serializer);
this.serializer = null;
}
if (this.output != null) {
this.output.close();
this.output = null;
}
}
// Ensure all is closed properly
protected void finalize() throws Throwable {
close();
super.finalize();
}
}
}