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Ant example source code file (PumpStreamHandler.java)

This example Ant source code file (PumpStreamHandler.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

executestreamhandler, inputstream, interruptedexception, io, ioexception, outputstream, outputstream, pumpstreamhandler, pumpstreamhandler, streampumper, streampumper, thread, thread

The PumpStreamHandler.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.taskdefs;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Copies standard output and error of subprocesses to standard output and
 * error of the parent process.
 *
 * @since Ant 1.2
 */
public class PumpStreamHandler implements ExecuteStreamHandler {

    private Thread outputThread;
    private Thread errorThread;
    private StreamPumper inputPump;

    private OutputStream out;
    private OutputStream err;
    private InputStream input;

    /**
     * Construct a new <code>PumpStreamHandler.
     * @param out the output <code>OutputStream.
     * @param err the error <code>OutputStream.
     * @param input the input <code>InputStream.
     */
    public PumpStreamHandler(OutputStream out, OutputStream err,
                             InputStream input) {
        this.out = out;
        this.err = err;
        this.input = input;
    }

    /**
     * Construct a new <code>PumpStreamHandler.
     * @param out the output <code>OutputStream.
     * @param err the error <code>OutputStream.
     */
    public PumpStreamHandler(OutputStream out, OutputStream err) {
        this(out, err, null);
    }

    /**
     * Construct a new <code>PumpStreamHandler.
     * @param outAndErr the output/error <code>OutputStream.
     */
    public PumpStreamHandler(OutputStream outAndErr) {
        this(outAndErr, outAndErr);
    }

    /**
     * Construct a new <code>PumpStreamHandler.
     */
    public PumpStreamHandler() {
        this(System.out, System.err);
    }

    /**
     * Set the <code>InputStream from which to read the
     * standard output of the process.
     * @param is the <code>InputStream.
     */
    public void setProcessOutputStream(InputStream is) {
        createProcessOutputPump(is, out);
    }

    /**
     * Set the <code>InputStream from which to read the
     * standard error of the process.
     * @param is the <code>InputStream.
     */
    public void setProcessErrorStream(InputStream is) {
        if (err != null) {
            createProcessErrorPump(is, err);
        }
    }

    /**
     * Set the <code>OutputStream by means of which
     * input can be sent to the process.
     * @param os the <code>OutputStream.
     */
    public void setProcessInputStream(OutputStream os) {
        if (input != null) {
            inputPump = createInputPump(input, os, true);
        } else {
            try {
                os.close();
            } catch (IOException e) {
                //ignore
            }
        }
    }

    /**
     * Start the <code>Threads.
     */
    public void start() {
        outputThread.start();
        errorThread.start();
        if (inputPump != null) {
            Thread inputThread = new Thread(inputPump);
            inputThread.setDaemon(true);
            inputThread.start();
        }
    }

    /**
     * Stop pumping the streams.
     */
    public void stop() {
        try {
            outputThread.join();
        } catch (InterruptedException e) {
            // ignore
        }
        try {
            errorThread.join();
        } catch (InterruptedException e) {
            // ignore
        }

        if (inputPump != null) {
            inputPump.stop();
        }

        try {
            err.flush();
        } catch (IOException e) {
            // ignore
        }
        try {
            out.flush();
        } catch (IOException e) {
            // ignore
        }
    }

    /**
     * Get the error stream.
     * @return <code>OutputStream.
     */
    protected OutputStream getErr() {
        return err;
    }

    /**
     * Get the output stream.
     * @return <code>OutputStream.
     */
    protected OutputStream getOut() {
        return out;
    }

    /**
     * Create the pump to handle process output.
     * @param is the <code>InputStream.
     * @param os the <code>OutputStream.
     */
    protected void createProcessOutputPump(InputStream is, OutputStream os) {
        outputThread = createPump(is, os);
    }

    /**
     * Create the pump to handle error output.
     * @param is the input stream to copy from.
     * @param os the output stream to copy to.
     */
    protected void createProcessErrorPump(InputStream is, OutputStream os) {
        errorThread = createPump(is, os);
    }

    /**
     * Creates a stream pumper to copy the given input stream to the
     * given output stream.
     * @param is the input stream to copy from.
     * @param os the output stream to copy to.
     * @return a thread object that does the pumping.
     */
    protected Thread createPump(InputStream is, OutputStream os) {
        return createPump(is, os, false);
    }

    /**
     * Creates a stream pumper to copy the given input stream to the
     * given output stream.
     * @param is the input stream to copy from.
     * @param os the output stream to copy to.
     * @param closeWhenExhausted if true close the inputstream.
     * @return a thread object that does the pumping.
     */
    protected Thread createPump(InputStream is, OutputStream os,
                                boolean closeWhenExhausted) {
        final Thread result
            = new Thread(new StreamPumper(is, os, closeWhenExhausted));
        result.setDaemon(true);
        return result;
    }

    /**
     * Creates a stream pumper to copy the given input stream to the
     * given output stream. Used for standard input.
     * @since Ant 1.6.3
     */
    /*protected*/ StreamPumper createInputPump(InputStream is, OutputStream os,
                                boolean closeWhenExhausted) {
        StreamPumper pumper = new StreamPumper(is, os, closeWhenExhausted);
        pumper.setAutoflush(true);
        return pumper;
    }

}

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