jodd.io.StreamGobbler Maven / Gradle / Ivy
// Copyright (c) 2003-present, Jodd Team (http://jodd.org)
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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package jodd.io;
import jodd.util.StringPool;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.PrintStream;
/**
* Consumes a stream.
* For any Process, the input and error streams must read even
* if the data written to these streams is not used by the application.
* The generally accepted solution for this problem is a stream gobbler thread
* that does nothing but consume data from an input stream until stopped.
*/
public class StreamGobbler extends Thread {
protected final InputStream is;
protected final String prefix;
protected final OutputStream out;
protected final Object lock = new Object();
protected boolean end = false;
public StreamGobbler(final InputStream is) {
this(is, null, null);
}
public StreamGobbler(final InputStream is, final OutputStream output) {
this(is, output, null);
}
public StreamGobbler(final InputStream is, final OutputStream output, final String prefix) {
this.is = is;
this.prefix = prefix;
this.out = output;
}
@Override
public void run() {
final InputStreamReader isr = new InputStreamReader(is);
try (final BufferedReader br = new BufferedReader(isr)) {
String line;
while ((line = br.readLine()) != null) {
if (out != null) {
if (prefix != null) {
out.write(prefix.getBytes());
}
out.write(line.getBytes());
out.write(StringPool.BYTES_NEW_LINE);
}
}
} catch (final IOException ioe) {
if (out != null) {
ioe.printStackTrace(new PrintStream(out));
}
} finally {
if (out != null) {
try {
out.flush();
} catch (final IOException ignore) {
}
}
}
synchronized (lock) {
lock.notifyAll();
end = true;
}
}
/**
* Waits for gobbler to end.
*/
public void waitFor() {
try {
synchronized (lock) {
if (!end) {
lock.wait();
}
}
}
catch (final InterruptedException ignore) {
Thread.currentThread().interrupt();
}
}
}