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Karaf Util contains utility classes used in different Karaf modules.
/*
* 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.karaf.util.process;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.IOException;
/**
* Copies all data from an input stream to an output stream.
*/
public class StreamPumper implements Runnable
{
private InputStream in;
private OutputStream out;
private volatile boolean finish;
private volatile boolean finished;
private boolean closeWhenExhausted;
private boolean nonBlocking;
private boolean autoflush;
private Throwable exception;
private int bufferSize = 128;
private boolean started;
private Thread thread;
/**
* Create a new stream pumper.
*
* @param in Input stream to read data from
* @param out 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 in, final OutputStream out, final boolean closeWhenExhausted) {
assert in != null;
assert out != null;
this.in = in;
this.out = out;
this.closeWhenExhausted = closeWhenExhausted;
}
/**
* Create a new stream pumper.
*
* @param in Input stream to read data from
* @param out Output stream to write data to.
*/
public StreamPumper(final InputStream in, final OutputStream out) {
this(in, out, false);
}
public InputStream getIn() {
return in;
}
public OutputStream getOut() {
return out;
}
/**
* Set whether data should be flushed through to the output stream.
*
* @param autoflush If true, push through data; if false, let it be buffered
*/
public void setAutoflush(boolean autoflush) {
this.autoflush = autoflush;
}
/**
* Set whether data should be read in a non blocking way.
* @param nonBlocking If true, data will be read in a non blocking mode
*/
public void setNonBlocking(boolean nonBlocking) {
this.nonBlocking = nonBlocking;
}
/**
* 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() {
synchronized (this) {
started = true;
finished = false;
finish = false;
thread = Thread.currentThread();
}
final byte[] buf = new byte[bufferSize];
int length;
try {
while (true) {
if (nonBlocking) {
while (in.available() > 0) {
length = in.read(buf);
if (length > 0) {
out.write(buf, 0, length);
if (autoflush) {
out.flush();
}
} else {
break;
}
}
Thread.sleep(50); // Pause to avoid tight loop if external proc is too slow
} else {
do {
length = in.read(buf);
if (length > 0) {
out.write(buf, 0, length);
if (autoflush) {
out.flush();
}
}
} while (length > 0);
}
boolean finish;
synchronized (this) {
finish = this.finish;
}
if (finish) {
break;
}
}
}
catch (Throwable t) {
synchronized (this) {
exception = t;
}
}
finally {
try {
out.flush();
} catch (IOException e) { }
if (closeWhenExhausted) {
try {
out.close();
} catch (IOException e) { }
}
synchronized (this) {
finished = true;
notifyAll();
}
}
}
/**
* Tells whether the end of the stream has been reached.
*
* @return true If the stream has been exhausted.
*/
public synchronized boolean isFinished() {
return finished;
}
/**
* This method blocks until the stream pumper finishes.
*
* @see #isFinished()
*/
public synchronized void waitFor() throws InterruptedException {
while (!isFinished()) {
wait();
}
}
/**
* Set the size in bytes of the read buffer.
*
* @param bufferSize the buffer size to use.
* @throws IllegalStateException if the StreamPumper is already running.
*/
public synchronized void setBufferSize(final int bufferSize) {
if (started) {
throw new IllegalStateException("Cannot set buffer size on a running StreamPumper");
}
this.bufferSize = bufferSize;
}
/**
* Get the size in bytes of the read buffer.
*
* @return The size of the read buffer.
*/
public synchronized int getBufferSize() {
return bufferSize;
}
/**
* Get the exception encountered, if any.
*
* @return The Exception encountered; or null if there was none.
*/
public synchronized Throwable getException() {
return exception;
}
/**
* Stop the pumper as soon as possible.
*
* Note that it may continue to block on the input stream
* but it will really stop the thread as soon as it gets EOF
* or any byte, and it will be marked as finished.
*/
public synchronized void stop() {
finish = true;
if (nonBlocking && thread != null && !finished) {
thread.interrupt();
}
notifyAll();
}
public InputStream getInputStream() {
return this.in;
}
}