/*
* 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 standard output and error of children streams to standard output and error of the parent.
*/
public class PumpStreamHandler {
private final InputStream in;
private final OutputStream out;
private final OutputStream err;
private final String name;
private StreamPumper outputPump;
private StreamPumper errorPump;
private StreamPumper inputPump;
//
// NOTE: May want to use a ThreadPool here, 3 threads per/pair seems kinda expensive :-(
//
public PumpStreamHandler(final InputStream in, final OutputStream out, final OutputStream err, String name) {
assert in != null;
assert out != null;
assert err != null;
assert name != null;
this.in = in;
this.out = out;
this.err = err;
this.name = name;
}
public PumpStreamHandler(final InputStream in, final OutputStream out, final OutputStream err) {
this(in, out, err, "<unknown>");
}
public PumpStreamHandler(final OutputStream out, final OutputStream err) {
this(null, out, err);
}
public PumpStreamHandler(final OutputStream outAndErr) {
this(outAndErr, outAndErr);
}
/**
* Set the input stream from which to read the standard output of the child.
*
* @param in the the child output stream.
*/
public void setChildOutputStream(final InputStream in) {
assert in != null;
createChildOutputPump(in, out);
}
/**
* Set the input stream from which to read the standard error of the child.
*
* @param in set the child error stream.
*/
public void setChildErrorStream(final InputStream in) {
assert in != null;
if (err != null) {
createChildErrorPump(in, err);
}
}
/**
* Set the output stream by means of which input can be sent to the child.
*
* @param out set the child output stream.
*/
public void setChildInputStream(final OutputStream out) {
assert out != null;
if (in != null) {
inputPump = createInputPump(in, out, true);
}
else {
try {
out.close();
} catch (IOException e) { }
}
}
/**
* Attach to a child streams from the given process.
*
* @param p The process to attach to.
*/
public void attach(final Process p) {
assert p != null;
setChildInputStream(p.getOutputStream());
setChildOutputStream(p.getInputStream());
setChildErrorStream(p.getErrorStream());
}
/**
* Start pumping the streams.
*/
public void start() {
if (outputPump != null) {
Thread thread = new Thread(outputPump);
thread.setDaemon(true);
thread.setName("Output pump for " + this.name);
thread.start();
}
if (errorPump != null) {
Thread thread = new Thread(errorPump);
thread.setDaemon(true);
thread.setName("Error pump for " + this.name);
thread.start();
}
if (inputPump != null) {
Thread thread = new Thread(inputPump);
thread.setDaemon(true);
thread.setName("Input pump for " + this.name);
thread.start();
}
}
/**
* Stop pumping the streams.
*/
public void stop() {
if (outputPump != null) {
try {
outputPump.stop();
outputPump.waitFor();
}
catch (InterruptedException e) {
// ignore
}
try {
outputPump.getIn().close();
} catch (IOException e) { }
}
if (errorPump != null) {
try {
errorPump.stop();
errorPump.waitFor();
}
catch (InterruptedException e) {
// ignore
}
try {
errorPump.getIn().close();
} catch (IOException e) { }
}
if (inputPump != null) {
inputPump.stop();
try {
inputPump.getOut().close();
} catch (IOException e) { }
}
try {
err.flush();
} catch (IOException e) { }
try {
out.flush();
} catch (IOException e) { }
}
/**
* Create the pump to handle child output.
*
* @param in the child input stream.
* @param out the child output stream.
*/
protected void createChildOutputPump(final InputStream in, final OutputStream out) {
assert in != null;
assert out != null;
outputPump = createPump(in, out);
}
/**
* Create the pump to handle error output.
*
* @param in the child input stream.
* @param out the child output stream.
*/
protected void createChildErrorPump(final InputStream in, final OutputStream out) {
assert in != null;
assert out != null;
errorPump = createPump(in, out);
}
/**
* Create a stream pumper to copy the given input stream to the given output stream.
*
* @param in the child input stream.
* @param out the child output stream.
* @return A thread object that does the pumping.
*/
protected StreamPumper createPump(final InputStream in, final OutputStream out) {
assert in != null;
assert out != null;
return createPump(in, out, false);
}
/**
* Create a stream pumper to copy the given input stream to the
* given output stream.
*
* @param in The input stream to copy from.
* @param out The output stream to copy to.
* @param closeWhenExhausted If true close the input stream.
* @return A thread object that does the pumping.
*/
protected StreamPumper createPump(final InputStream in, final OutputStream out, final boolean closeWhenExhausted) {
assert in != null;
assert out != null;
StreamPumper pumper = new StreamPumper(in, out, closeWhenExhausted);
return pumper;
}
/**
* Create a stream pumper to copy the given input stream to the
* given output stream. Used for standard input.
*
* @param in The input stream to copy from.
* @param out The output stream to copy to.
* @param closeWhenExhausted If true close the input stream.
* @return A thread object that does the pumping.
*/
protected StreamPumper createInputPump(final InputStream in, final OutputStream out, final boolean closeWhenExhausted) {
assert in != null;
assert out != null;
StreamPumper pumper = new StreamPumper(in, out, closeWhenExhausted);
pumper.setNonBlocking(true);
pumper.setAutoflush(true);
return pumper;
}
public StreamPumper getOutputPump() {
return this.outputPump;
}
public StreamPumper getErrorPump() {
return this.errorPump;
}
}