// Copyright 2004, 2005 The Apache Software Foundation
//
// Licensed 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.tapestry.contrib.inspector;
import java.io.ByteArrayOutputStream;
import java.io.CharArrayWriter;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.tapestry.BaseComponent;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRender;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.Tapestry;
import org.apache.tapestry.event.PageDetachListener;
import org.apache.tapestry.event.PageEvent;
import org.apache.tapestry.util.io.BinaryDumpOutputStream;
/**
* Component of the {@link Inspector} page used to display
* the properties of the {@link org.apache.tapestry.IEngine} as well as a serialized view of it.
* Also, the {@link org.apache.tapestry.request.RequestContext} is dumped out.
*
*
* @author Howard Lewis Ship
*
**/
public abstract class ShowEngine extends BaseComponent implements PageDetachListener
{
private byte[] serializedEngine;
public void pageDetached(PageEvent event)
{
serializedEngine = null;
}
/**
* Workaround for OGNL limitation --- OGNL can't dereference
* past class instances.
*
* @since 2.2
*
**/
public String getEngineClassName()
{
return getPage().getEngine().getClass().getName();
}
private byte[] getSerializedEngine()
{
if (serializedEngine == null)
buildSerializedEngine();
return serializedEngine;
}
private void buildSerializedEngine()
{
ByteArrayOutputStream bos = null;
ObjectOutputStream oos = null;
try
{
bos = new ByteArrayOutputStream();
oos = new ObjectOutputStream(bos);
// Write the application object to the stream.
oos.writeObject(getPage().getEngine());
// Extract the application as an array of bytes.
serializedEngine = bos.toByteArray();
}
catch (IOException ex)
{
throw new ApplicationRuntimeException(
Tapestry.getMessage("ShowEngine.could-not-serialize"),
ex);
}
finally
{
close(oos);
close(bos);
}
// It would be nice to deserialize the application object now, but in
// practice, that fails due to class loader problems.
}
private void close(OutputStream stream)
{
if (stream == null)
return;
try
{
stream.close();
}
catch (IOException ex)
{
// Ignore.
}
}
public int getEngineByteCount()
{
return getSerializedEngine().length;
}
public IRender getEngineDumpDelegate()
{
return new IRender()
{
public void render(IMarkupWriter writer, IRequestCycle cycle)
{
dumpSerializedEngine(writer);
}
};
}
private void dumpSerializedEngine(IMarkupWriter responseWriter)
{
CharArrayWriter writer = null;
BinaryDumpOutputStream bos = null;
try
{
// Because IReponseWriter doesn't implement the
// java.io.Writer interface, we have to buffer this
// stuff then pack it in all at once. Kind of a waste!
writer = new CharArrayWriter();
bos = new BinaryDumpOutputStream(writer);
bos.setBytesPerLine(32);
bos.write(getSerializedEngine());
bos.close();
responseWriter.print(writer.toString());
}
catch (IOException ex)
{
// Ignore.
}
finally
{
if (bos != null)
{
try
{
bos.close();
}
catch (IOException ex)
{
// Ignore.
}
}
if (writer != null)
{
writer.reset();
writer.close();
}
}
}
}