Tomcat example source code file (IdentityOutputFilter.java)

This example Tomcat source code file (IdentityOutputFilter.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

bytechunk, bytechunk, encoding, encoding, encoding_name, identityoutputfilter, io, ioexception, ioexception, outputbuffer, outputfilter, response, response, string

The Tomcat IdentityOutputFilter.java source code

/*
 *  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.coyote.http11.filters;

import java.io.IOException;

import org.apache.tomcat.util.buf.ByteChunk;

import org.apache.coyote.OutputBuffer;
import org.apache.coyote.Response;
import org.apache.coyote.http11.OutputFilter;

/**
 * Identity output filter.
 * 
 * @author Remy Maucherat
 */
public class IdentityOutputFilter implements OutputFilter {


    // -------------------------------------------------------------- Constants


    protected static final String ENCODING_NAME = "identity";
    protected static final ByteChunk ENCODING = new ByteChunk();


    // ----------------------------------------------------- Static Initializer


    static {
        ENCODING.setBytes(ENCODING_NAME.getBytes(), 0, ENCODING_NAME.length());
    }


    // ----------------------------------------------------- Instance Variables


    /**
     * Content length.
     */
    protected long contentLength = -1;


    /**
     * Remaining bytes.
     */
    protected long remaining = 0;


    /**
     * Next buffer in the pipeline.
     */
    protected OutputBuffer buffer;


    // ------------------------------------------------------------- Properties


    /**
     * Get content length.
     */
    public long getContentLength() {
        return contentLength;
    }


    /**
     * Get remaining bytes.
     */
    public long getRemaining() {
        return remaining;
    }


    // --------------------------------------------------- OutputBuffer Methods


    /**
     * Write some bytes.
     * 
     * @return number of bytes written by the filter
     */
    public int doWrite(ByteChunk chunk, Response res)
        throws IOException {

        int result = -1;

        if (contentLength >= 0) {
            if (remaining > 0) {
                result = chunk.getLength();
                if (result > remaining) {
                    // The chunk is longer than the number of bytes remaining
                    // in the body; changing the chunk length to the number
                    // of bytes remaining
                    chunk.setBytes(chunk.getBytes(), chunk.getStart(), 
                                   (int) remaining);
                    result = (int) remaining;
                    remaining = 0;
                } else {
                    remaining = remaining - result;
                }
                buffer.doWrite(chunk, res);
            } else {
                // No more bytes left to be written : return -1 and clear the 
                // buffer
                chunk.recycle();
                result = -1;
            }
        } else {
            // If no content length was set, just write the bytes
            buffer.doWrite(chunk, res);
            result = chunk.getLength();
        }

        return result;

    }


    // --------------------------------------------------- OutputFilter Methods


    /**
     * Some filters need additional parameters from the response. All the 
     * necessary reading can occur in that method, as this method is called
     * after the response header processing is complete.
     */
    public void setResponse(Response response) {
        contentLength = response.getContentLengthLong();
        remaining = contentLength;
    }


    /**
     * Set the next buffer in the filter pipeline.
     */
    public void setBuffer(OutputBuffer buffer) {
        this.buffer = buffer;
    }


    /**
     * End the current request. It is acceptable to write extra bytes using
     * buffer.doWrite during the execution of this method.
     */
    public long end()
        throws IOException {

        if (remaining > 0)
            return remaining;
        return 0;

    }


    /**
     * Make the filter ready to process the next request.
     */
    public void recycle() {
        contentLength = -1;
        remaining = 0;
    }


    /**
     * Return the name of the associated encoding; Here, the value is 
     * "identity".
     */
    public ByteChunk getEncodingName() {
        return ENCODING;
    }


}