package org.jboss.seam.web;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPOutputStream;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Superclass of Seam components that serve up
* "resources" to the client via the Seam
* resource servlet. Note that since a filter is
* potentially called outside of a set of Seam
* contexts, it is not a true Seam component.
* However, we are able to reuse the functionality
* for component scanning, installation and
* configuration for filters. All resources
* must extend this class.
*
* @author Shane Bryzak
*
*/
public abstract class AbstractResource
{
private ServletContext context;
protected ServletContext getServletContext()
{
return context;
}
public void setServletContext(ServletContext context)
{
this.context = context;
}
public abstract void getResource(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException;
public abstract String getResourcePath();
protected OutputStream selectOutputStream(HttpServletRequest request, HttpServletResponse response)
throws IOException
{
String acceptEncoding = request.getHeader("Accept-Encoding");
String mimeType = response.getContentType();
if (isGzipEnabled()
&& acceptEncoding != null
&& acceptEncoding.length() > 0
&& acceptEncoding.indexOf("gzip") > -1
&& isCompressedMimeType(mimeType))
{
return new GZIPResponseStream(response);
}
else
{
return response.getOutputStream();
}
}
protected boolean isCompressedMimeType(String mimeType)
{
return mimeType.matches("text/.+");
}
protected boolean isGzipEnabled()
{
return true;
}
/*
* Copyright 2004-2008 the original author or authors.
*
* 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.
*
* @See org/springframework/js/resource/ResourceServlet.java
*/
private class GZIPResponseStream extends ServletOutputStream
{
private ByteArrayOutputStream byteStream = null;
private GZIPOutputStream gzipStream = null;
private boolean closed = false;
private HttpServletResponse response = null;
private ServletOutputStream servletStream = null;
public GZIPResponseStream(HttpServletResponse response) throws IOException
{
super();
closed = false;
this.response = response;
this.servletStream = response.getOutputStream();
byteStream = new ByteArrayOutputStream();
gzipStream = new GZIPOutputStream(byteStream);
}
@Override
public void close() throws IOException
{
if (closed)
{
throw new IOException("This output stream has already been closed");
}
gzipStream.finish();
byte[] bytes = byteStream.toByteArray();
response.setContentLength(bytes.length);
response.addHeader("Content-Encoding", "gzip");
servletStream.write(bytes);
servletStream.flush();
servletStream.close();
closed = true;
}
@Override
public void flush() throws IOException
{
if (closed)
{
throw new IOException("Cannot flush a closed output stream");
}
gzipStream.flush();
}
@Override
public void write(int b) throws IOException
{
if (closed)
{
throw new IOException("Cannot write to a closed output stream");
}
gzipStream.write((byte) b);
}
@Override
public void write(byte b[]) throws IOException
{
write(b, 0, b.length);
}
@Override
public void write(byte b[], int off, int len) throws IOException
{
if (closed)
{
throw new IOException("Cannot write to a closed output stream");
}
gzipStream.write(b, off, len);
}
@SuppressWarnings("unused")
public boolean closed()
{
return (this.closed);
}
@SuppressWarnings("unused")
public void reset()
{
// noop
}
}
}