outputbuffer.java

Tomcat 4.1与WebServer集成组件的源代码包.

/*
 * ====================================================================
 * 
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
 *
 * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software
 *    Foundation" must not be used to endorse or promote products derived
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 * 5. Products derived from this software may not be called "Apache"
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 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * [Additional notices, if required by prior licensing conditions]
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 */ 

package org.apache.coyote.tomcat4;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.io.Writer;
import java.util.Hashtable;

import org.apache.tomcat.util.buf.ByteChunk;
import org.apache.tomcat.util.buf.C2BConverter;
import org.apache.tomcat.util.buf.CharChunk;

import org.apache.coyote.Response;


/**
 * The buffer used by Tomcat response. This is a derivative of the Tomcat 3.3
 * OutputBuffer, with the removal of some of the state handling (which in 
 * Coyote is mostly the Processor's responsability).
 *
 * @author Costin Manolache
 * @author Remy Maucherat
 */
public class OutputBuffer extends Writer
    implements ByteChunk.ByteOutputChannel, CharChunk.CharOutputChannel {


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


    public static final String DEFAULT_ENCODING = 
        org.apache.coyote.Constants.DEFAULT_CHARACTER_ENCODING;
    public static final int DEFAULT_BUFFER_SIZE = 8*1024;
    static final int debug = 0;


    // The buffer can be used for byte[] and char[] writing
    // ( this is needed to support ServletOutputStream and for
    // efficient implementations of templating systems )
    public final int INITIAL_STATE = 0;
    public final int CHAR_STATE = 1;
    public final int BYTE_STATE = 2;


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


    /**
     * The byte buffer.
     */
    private ByteChunk bb;


    /**
     * The chunk buffer.
     */
    private CharChunk cb;


    /**
     * State of the output buffer.
     */
    private int state = 0;


    /**
     * Number of bytes written.
     */
    private int bytesWritten = 0;


    /**
     * Number of chars written.
     */
    private int charsWritten = 0;


    /**
     * Flag which indicates if the output buffer is closed.
     */
    private boolean closed = false;


    /**
     * Do a flush on the next operation.
     */
    private boolean doFlush = false;


    /**
     * Byte chunk used to output bytes.
     */
    private ByteChunk outputChunk = new ByteChunk();


    /**
     * Encoding to use.
     */
    private String enc;


    /**
     * Encoder is set.
     */
    private boolean gotEnc = false;


    /**
     * List of encoders.
     */
    protected Hashtable encoders = new Hashtable();


    /**
     * Current char to byte converter.
     */
    protected C2BConverter conv;


    /**
     * Associated Coyote response.
     */
    private Response coyoteResponse;


    /**
     * Suspended flag. All output bytes will be swallowed if this is true.
     */
    private boolean suspended = false;


    // ----------------------------------------------------------- Constructors


    /**
     * Default constructor. Allocate the buffer with the default buffer size.
     */
    public OutputBuffer() {

        this(DEFAULT_BUFFER_SIZE);

    }


    /**
     * Alternate constructor which allows specifying the initial buffer size.
     * 
     * @param size Buffer size to use
     */
    public OutputBuffer(int size) {

        bb = new ByteChunk(size);
        bb.setLimit(size);
        bb.setByteOutputChannel(this);
        cb = new CharChunk(size);
        cb.setCharOutputChannel(this);
        cb.setLimit(size);

    }


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


    /**
     * Associated Coyote response.
     * 
     * @param coyoteResponse Associated Coyote response
     */
    public void setResponse(Response coyoteResponse) {
	this.coyoteResponse = coyoteResponse;
    }


    /**
     * Get associated Coyote response.
     * 
     * @return the associated Coyote response
     */
    public Response getResponse() {
        return this.coyoteResponse;
    }


    /**
     * Is the response output suspended ?
     * 
     * @return suspended flag value
     */
    public boolean isSuspended() {
        return this.suspended;
    }


    /**
     * Set the suspended flag.
     * 
     * @param suspended New suspended flag value
     */
    public void setSuspended(boolean suspended) {
        this.suspended = suspended;
    }


    // --------------------------------------------------------- Public Methods


    /**
     * Recycle the output buffer.
     */
    public void recycle() {

	if (debug > 0)
            log("recycle()");

	state = INITIAL_STATE;
	bytesWritten = 0;
	charsWritten = 0;

        cb.recycle();
        bb.recycle(); 
        closed = false;
        suspended = false;

        if (conv!= null) {
            conv.recycle();
        }

        gotEnc = false;
        enc = null;

    }


    /**
     * Close the output buffer. This tries to calculate the response size if 
     * the response has not been committed yet.
     * 
     * @throws IOException An underlying IOException occurred
     */
    public void close()
        throws IOException {

        if (closed)
            return;
        if (suspended)
            return;

        if ((!coyoteResponse.isCommitted()) 
            && (coyoteResponse.getContentLength() == -1)) {
            // Flushing the char buffer
            if (state == CHAR_STATE) {
                cb.flushBuffer();
                state = BYTE_STATE;
            }
            // If this didn't cause a commit of the response, the final content
            // length can be calculated
            if (!coyoteResponse.isCommitted()) {
                coyoteResponse.setContentLength(bb.getLength());
            }
        }

        flush();
        closed = true;

        coyoteResponse.finish();

    }


    /**
     * Flush bytes or chars contained in the buffer.
     * 
     * @throws IOException An underlying IOException occurred
     */
    public void flush()
        throws IOException {

        if (suspended)
            return;

        doFlush = true;
        if (state == CHAR_STATE) {
            cb.flushBuffer();