Ant example source code file (LineOrientedOutputStream.java)

This example Ant source code file (LineOrientedOutputStream.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 - Ant tags/keywords

bytearrayoutputstream, bytearrayoutputstream, cr, cr, intial_size, io, ioexception, ioexception, lf, lf, lineorientedoutputstream, outputstream

The LineOrientedOutputStream.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.tools.ant.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Invokes {@link #processLine processLine} whenever a full line has
 * been written to this stream.
 *
 * <p>Tries to be smart about line separators.

 */
public abstract class LineOrientedOutputStream extends OutputStream {

    /** Initial buffer size. */
    private static final int INTIAL_SIZE = 132;

    /** Carriage return */
    private static final int CR = 0x0d;

    /** Linefeed */
    private static final int LF = 0x0a;

    private ByteArrayOutputStream buffer
        = new ByteArrayOutputStream(INTIAL_SIZE);
    private boolean skip = false;

    /**
     * Write the data to the buffer and flush the buffer, if a line
     * separator is detected.
     *
     * @param cc data to log (byte).
     * @throws IOException if there is an error.
     */
    public final void write(int cc) throws IOException {
        final byte c = (byte) cc;
        if ((c == LF) || (c == CR)) {
            if (!skip) {
              processBuffer();
            }
        } else {
            buffer.write(cc);
        }
        skip = (c == CR);
    }

    /**
     * Flush this log stream
     * @throws IOException if there is an error.
     */
    public final void flush() throws IOException {
        if (buffer.size() > 0) {
            processBuffer();
        }
    }

    /**
     * Converts the buffer to a string and sends it to
     * <code>processLine
     * @throws IOException if there is an error.
     */
    protected void processBuffer() throws IOException {
        try {
            processLine(buffer.toString());
        } finally {
            buffer.reset();
        }
    }

    /**
     * Processes a line.
     *
     * @param line the line to log.
     * @throws IOException if there is an error.
     */
    protected abstract void processLine(String line) throws IOException;

    /**
     * Writes all remaining
     * @throws IOException if there is an error.
     */
    public final void close() throws IOException {
        if (buffer.size() > 0) {
            processBuffer();
        }
        super.close();
    }

    /**
     * Write a block of characters to the output stream
     *
     * @param b the array containing the data
     * @param off the offset into the array where data starts
     * @param len the length of block
     *
     * @throws IOException if the data cannot be written into the stream.
     */
    public final void write(byte[] b, int off, int len) throws IOException {
        // find the line breaks and pass other chars through in blocks
        int offset = off;
        int blockStartOffset = offset;
        int remaining = len;
        while (remaining > 0) {
            while (remaining > 0 && b[offset] != LF && b[offset] != CR) {
                offset++;
                remaining--;
            }
            // either end of buffer or a line separator char
            int blockLength = offset - blockStartOffset;
            if (blockLength > 0) {
                buffer.write(b, blockStartOffset, blockLength);
            }
            while (remaining > 0 && (b[offset] == LF || b[offset] == CR)) {
                write(b[offset]);
                offset++;
                remaining--;
            }
            blockStartOffset = offset;
        }
    }

}