org.pitest.util.StreamMonitor Maven / Gradle / Ivy
/*
* Copyright 2010 Henry Coles
*
* 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.
*/
package org.pitest.util;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.function.Consumer;
import java.util.logging.Logger;
public class StreamMonitor extends Thread implements Monitor {
private static final Logger LOG = Log.getLogger();
private final InputStream in;
private final Consumer inputHandler;
/**
* Constructor.
* @param in stream to read from
* @param inputHandler all characters read from {@code in} will be forwarded
* line by line (without the newline) to this handler.
*/
public StreamMonitor(final InputStream in,
final Consumer inputHandler) {
super("PIT Stream Monitor");
this.in = in;
this.inputHandler = inputHandler;
setDaemon(true);
}
@Override
public void requestStart() {
start();
}
@Override
public void run() {
BufferedReader reader = new BufferedReader(new InputStreamReader(this.in));
while (!this.isInterrupted()) {
readFromStream(reader);
}
}
private void readFromStream(final BufferedReader reader) {
try {
// If child JVM crashes reading stdout/stderr seems to sometimes
// block and consume 100% cpu, so check stream is available first.
// May still be an issue if child crashes during later read . . .
if (!reader.ready()) {
Thread.sleep(100);
return;
}
String output;
while ( ( output = reader.readLine() ) != null ) {
this.inputHandler.accept(output);
}
} catch (final IOException e) {
requestStop();
LOG.fine("No longer able to read stream.");
} catch (final InterruptedException e) {
Thread.currentThread().interrupt();
}
}
@Override
public void requestStop() {
this.interrupt();
}
}