Tomcat example source code file (InputBuffer.java)

This example Tomcat source code file (InputBuffer.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

b2cconverter, b2cconverter, byte_state, bytechunk, bytechunk, char_state, char_state, charchunk, initial_state, inputbuffer, io, ioexception, ioexception, request, security, string, util

The Tomcat InputBuffer.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.catalina.connector;

import java.io.IOException;
import java.io.Reader;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.HashMap;

import org.apache.catalina.security.SecurityUtil;
import org.apache.coyote.ActionCode;
import org.apache.coyote.Request;
import org.apache.tomcat.util.buf.B2CConverter;
import org.apache.tomcat.util.buf.ByteChunk;
import org.apache.tomcat.util.buf.CharChunk;


/**
 * The buffer used by Tomcat request. This is a derivative of the Tomcat 3.3
 * OutputBuffer, adapted to handle input instead of output. This allows 
 * complete recycling of the facade objects (the ServletInputStream and the
 * BufferedReader).
 *
 * @author Remy Maucherat
 */
public class InputBuffer extends Reader
    implements ByteChunk.ByteInputChannel, CharChunk.CharInputChannel,
               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;

    // The buffer can be used for byte[] and char[] reading
    // ( this is needed to support ServletInputStream and BufferedReader )
    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 read.
     */
    private int bytesRead = 0;


    /**
     * Number of chars read.
     */
    private int charsRead = 0;


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


    /**
     * Byte chunk used to input bytes.
     */
    private ByteChunk inputChunk = new ByteChunk();


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


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


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


    /**
     * Current byte to char converter.
     */
    protected B2CConverter conv;


    /**
     * Associated Coyote request.
     */
    private Request coyoteRequest;


    /**
     * Buffer position.
     */
    private int markPos = -1;


    /**
     * Buffer size.
     */
    private int size = -1;


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


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

        this(DEFAULT_BUFFER_SIZE);

    }


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

        this.size = size;
        bb = new ByteChunk(size);
        bb.setLimit(size);
        bb.setByteInputChannel(this);
        cb = new CharChunk(size);
        cb.setLimit(size);
        cb.setOptimizedWrite(false);
        cb.setCharInputChannel(this);
        cb.setCharOutputChannel(this);

    }


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


    /**
     * Associated Coyote request.
     * 
     * @param coyoteRequest Associated Coyote request
     */
    public void setRequest(Request coyoteRequest) {
	this.coyoteRequest = coyoteRequest;
    }


    /**
     * Get associated Coyote request.
     * 
     * @return the associated Coyote request
     */
    public Request getRequest() {
        return this.coyoteRequest;
    }


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


    /**
     * Recycle the output buffer.
     */
    public void recycle() {
        
        state = INITIAL_STATE;
        bytesRead = 0;
        charsRead = 0;
        
        // If usage of mark made the buffer too big, reallocate it
        if (cb.getChars().length > size) {
            cb = new CharChunk(size);
            cb.setLimit(size);
            cb.setOptimizedWrite(false);
            cb.setCharInputChannel(this);
            cb.setCharOutputChannel(this);
        } else {
            cb.recycle();
        }
        markPos = -1;
        bb.recycle(); 
        closed = false;
        
        if (conv != null) {
            conv.recycle();
        }
        
        gotEnc = false;
        enc = null;
        
    }


    /**
     * Clear cached encoders (to save memory for Comet requests).
     */
    public void clearEncoders() {
        encoders.clear();
    }
    
    
    /**
     * Close the input buffer.
     * 
     * @throws IOException An underlying IOException occurred
     */
    public void close()
        throws IOException {
        closed = true;
    }


    public int available() {
        int available = 0;
        if (state == BYTE_STATE) {
            available = bb.getLength();
        } else if (state == CHAR_STATE) {
            available = cb.getLength();
        }
        if (available == 0) {
            coyoteRequest.action(ActionCode.ACTION_AVAILABLE, null);
            available = (coyoteRequest.getAvailable() > 0) ? 1 : 0;
        }
        return available;
    }


    // ------------------------------------------------- Bytes Handling Methods


    /** 
     * Reads new bytes in the byte chunk.
     * 
     * @param cbuf Byte buffer to be written to the response
     * @param off Offset
     * @param len Length
     * 
     * @throws IOException An underlying IOException occurred
     */
    public int realReadBytes(byte cbuf[], int off, int len)
	throws IOException {

        if (closed)
            return -1;
        if (coyoteRequest == null)
            return -1;

        if(state == INITIAL_STATE)
            state = BYTE_STATE;

        int result = coyoteRequest.doRead(bb);

        return result;

    }


    public int readByte()
        throws IOException {
        return bb.substract();
    }


    public int read(byte[] b, int off, int len)
        throws IOException {
        return bb.substract(b, off, len);
    }


    // ------------------------------------------------- Chars Handling Methods


    /**
     * Since the converter will use append, it is possible to get chars to
     * be removed from the buffer for "writing". Since the chars have already
     * been read before, they are ignored. If a mark was set, then the
     * mark is lost.
     */
    public void realWriteChars(char c[], int off, int len) 
        throws IOException {
        markPos = -1;
        cb.setOffset(0);
        cb.setEnd(0);
    }


    public void setEncoding(String s) {
        enc = s;
    }


    public int realReadChars(char cbuf[], int off, int len)
        throws IOException {

        if (!gotEnc)
            setConverter();

        if (bb.getLength() <= 0) {
            int nRead = realReadBytes(bb.getBytes(), 0, bb.getBytes().length);
            if (nRead < 0) {
                return -1;
            }
        }

        if (markPos == -1) {
            cb.setOffset(0);
            cb.setEnd(0);
        }

        state = CHAR_STATE;
        conv.convert(bb, cb, len);
        bb.setOffset(bb.getEnd());

        return cb.getLength();

    }


    public int read()
        throws IOException {
        return cb.substract();
    }


    public int read(char[] cbuf)
        throws IOException {
        return read(cbuf, 0, cbuf.length);
    }


    public int read(char[] cbuf, int off, int len)
        throws IOException {
        return cb.substract(cbuf, off, len);
    }


    public long skip(long n)
        throws IOException {

        if (n < 0) {
            throw new IllegalArgumentException();
        }

        long nRead = 0;
        while (nRead < n) {
            if (cb.getLength() >= n) {
                cb.setOffset(cb.getStart() + (int) n);
                nRead = n;
            } else {
                nRead += cb.getLength();
                cb.setOffset(cb.getEnd());
                int toRead = 0;
                if (cb.getChars().length < (n - nRead)) {
                    toRead = cb.getChars().length;
                } else {
                    toRead = (int) (n - nRead);
                }
                int nb = realReadChars(cb.getChars(), 0, toRead);
                if (nb < 0)
                    break;
            }
        }

        return nRead;

    }


    public boolean ready()
        throws IOException {
        return (available() > 0);
    }


    public boolean markSupported() {
        return true;
    }


    public void mark(int readAheadLimit)
        throws IOException {
        if (cb.getLength() <= 0) {
            cb.setOffset(0);
            cb.setEnd(0);
        } else {
            if ((cb.getBuffer().length > (2 * size)) 
                && (cb.getLength()) < (cb.getStart())) {
                System.arraycopy(cb.getBuffer(), cb.getStart(), 
                                 cb.getBuffer(), 0, cb.getLength());
                cb.setEnd(cb.getLength());
                cb.setOffset(0);
            }
        }
        int offset = readAheadLimit;
        if (offset < size) {
            offset = size;
        }
        cb.setLimit(cb.getStart() + offset);
        markPos = cb.getStart();
    }


    public void reset()
        throws IOException {
        if (state == CHAR_STATE) {
            if (markPos < 0) {
                cb.recycle();
                markPos = -1;
                throw new IOException();
            } else {
                cb.setOffset(markPos);
            }
        } else {
            bb.recycle();
        }
    }


    public void checkConverter() 
        throws IOException {

        if (!gotEnc)
            setConverter();

    }


    protected void setConverter()
        throws IOException {

        if (coyoteRequest != null)
            enc = coyoteRequest.getCharacterEncoding();

        gotEnc = true;
        if (enc == null)
            enc = DEFAULT_ENCODING;
        conv = (B2CConverter) encoders.get(enc);
        if (conv == null) {
            if (SecurityUtil.isPackageProtectionEnabled()){
                try{
                    conv = (B2CConverter)AccessController.doPrivileged(
                            new PrivilegedExceptionAction(){

                                public Object run() throws IOException{
                                    return new B2CConverter(enc);
                                }

                            }
                    );              
                }catch(PrivilegedActionException ex){
                    Exception e = ex.getException();
                    if (e instanceof IOException)
                        throw (IOException)e; 
                }
            } else {
                conv = new B2CConverter(enc);
            }
            encoders.put(enc, conv);
        }

    }

}