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A lightweight library to execute external processes from Java.
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/*
* Copyright (C) 2014 ZeroTurnaround
* Contains fragments of code from Apache Commons Exec, rights owned
* by Apache Software Foundation (ASF).
*
* Licensed 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.
*
* NOTICE: This file originates from the Apache Commons Exec package.
* It has been modified to fit our needs.
*
* The following is the original header of the file in Apache Commons Exec:
*
* 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.zeroturnaround.exec.stream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Copies all data from an input stream to an output stream.
*/
public class StreamPumper implements Runnable {
private static final Logger log = LoggerFactory.getLogger(StreamPumper.class);
/** the default size of the internal buffer for copying the streams */
private static final int DEFAULT_SIZE = 1024;
/** the input stream to pump from */
private final InputStream is;
/** the output stream to pmp into */
private final OutputStream os;
/** the size of the internal buffer for copying the streams */
private final int size;
/** was the end of the stream reached */
private boolean finished;
/** close the output stream when exhausted */
private final boolean closeWhenExhausted;
/** flush the output stream after each write */
private final boolean flushImmediately;
/**
* Create a new stream pumper.
*
* @param is input stream to read data from
* @param os output stream to write data to.
* @param closeWhenExhausted if true, the output stream will be closed when the input is exhausted.
* @param flushImmediately flush the output stream whenever data was written to it
*/
public StreamPumper(final InputStream is, final OutputStream os,
final boolean closeWhenExhausted, boolean flushImmediately) {
this.is = is;
this.os = os;
this.size = DEFAULT_SIZE;
this.closeWhenExhausted = closeWhenExhausted;
this.flushImmediately = flushImmediately;
}
/**
* Create a new stream pumper.
*
* @param is input stream to read data from
* @param os output stream to write data to.
* @param closeWhenExhausted if true, the output stream will be closed when the input is exhausted.
* @param size the size of the internal buffer for copying the streams
* @param flushImmediately flush the output stream whenever data was written to it
*/
public StreamPumper(final InputStream is, final OutputStream os,
final boolean closeWhenExhausted, final int size, boolean flushImmediately) {
this.is = is;
this.os = os;
this.size = (size > 0 ? size : DEFAULT_SIZE);
this.closeWhenExhausted = closeWhenExhausted;
this.flushImmediately = flushImmediately;
}
/**
* Create a new stream pumper.
*
* @param is input stream to read data from
* @param os output stream to write data to.
* @param closeWhenExhausted if true, the output stream will be closed when the input is exhausted.
*/
public StreamPumper(final InputStream is, final OutputStream os,
final boolean closeWhenExhausted) {
this.is = is;
this.os = os;
this.size = DEFAULT_SIZE;
this.closeWhenExhausted = closeWhenExhausted;
this.flushImmediately = false;
}
/**
* Create a new stream pumper.
*
* @param is input stream to read data from
* @param os output stream to write data to.
* @param closeWhenExhausted if true, the output stream will be closed when the input is exhausted.
* @param size the size of the internal buffer for copying the streams
*/
public StreamPumper(final InputStream is, final OutputStream os,
final boolean closeWhenExhausted, final int size) {
this.is = is;
this.os = os;
this.size = (size > 0 ? size : DEFAULT_SIZE);
this.closeWhenExhausted = closeWhenExhausted;
this.flushImmediately = false;
}
/**
* Create a new stream pumper.
*
* @param is input stream to read data from
* @param os output stream to write data to.
*/
public StreamPumper(final InputStream is, final OutputStream os) {
this(is, os, false);
}
/**
* Copies data from the input stream to the output stream. Terminates as
* soon as the input stream is closed or an error occurs.
*/
public void run() {
log.trace("{} started.", this);
synchronized (this) {
// Just in case this object is reused in the future
finished = false;
}
final byte[] buf = new byte[this.size];
int length;
try {
while ((length = is.read(buf)) > 0) {
os.write(buf, 0, length);
if(flushImmediately) {
os.flush();
}
}
} catch (Exception e) {
// nothing to do - happens quite often with watchdog
} finally {
log.trace("{} finished.", this);
if (closeWhenExhausted) {
try {
os.close();
} catch (IOException e) {
log.error("Got exception while closing exhausted output stream", e);
}
}
synchronized (this) {
finished = true;
notifyAll();
}
}
}
/**
* Tells whether the end of the stream has been reached.
*
* @return true is the stream has been exhausted.
*/
public synchronized boolean isFinished() {
return finished;
}
/**
* This method blocks until the stream pumper finishes.
*
* @see #isFinished()
* @throws InterruptedException throws when the waiting is interrupted
*/
public synchronized void waitFor() throws InterruptedException {
while (!isFinished()) {
wait();
}
}
}