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/*
* SonarQube, open source software quality management tool.
* Copyright (C) 2008-2014 SonarSource
* mailto:contact AT sonarsource DOT com
*
* SonarQube is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* SonarQube is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.sonar.process;
import org.apache.commons.io.FileUtils;
import java.io.File;
import java.io.IOException;
/**
* Process inter-communication to :
* <ul>
* <li>share status of child process</li>
* <li>stop child process</li>
* </ul>
*
* <p/>
* It relies on files shared by both processes. Following alternatives were considered but not selected :
* <ul>
* <li>JMX beans over RMI: network issues (mostly because of Java reverse-DNS) + requires to configure and open a new port</li>
* <li>simple socket protocol: same drawbacks are RMI connection</li>
* <li>java.lang.Process#destroy(): shutdown hooks are not executed on some OS (mostly MSWindows)</li>
* <li>execute OS-specific commands (for instance kill on *nix): OS-specific, so hell to support. Moreover how to get identify a process ?</li>
* </ul>
*/
public class ProcessCommands {
private final File readyFile, stopFile;
public ProcessCommands(File directory, String processKey) {
if (!directory.isDirectory() || !directory.exists()) {
throw new IllegalArgumentException("Not a valid directory: " + directory);
}
this.readyFile = new File(directory, processKey + ".ready");
this.stopFile = new File(directory, processKey + ".stop");
}
// visible for tests
ProcessCommands(File readyFile, File stopFile) {
this.readyFile = readyFile;
this.stopFile = stopFile;
}
public void prepare() {
deleteFile(readyFile);
deleteFile(stopFile);
}
public void endWatch() {
// do not fail if files can't be deleted
FileUtils.deleteQuietly(readyFile);
FileUtils.deleteQuietly(stopFile);
}
public boolean isReady() {
return readyFile.exists();
}
/**
* To be executed by child process to declare that it's ready
*/
public void setReady() {
createFile(readyFile);
}
/**
* To be executed by monitor process to ask for child process termination
*/
public void askForStop() {
createFile(stopFile);
}
public boolean askedForStop() {
return stopFile.exists();
}
File getReadyFile() {
return readyFile;
}
File getStopFile() {
return stopFile;
}
private void createFile(File file) {
try {
FileUtils.touch(file);
} catch (IOException e) {
throw new IllegalStateException(String.format("Fail to create file %s", file), e);
}
}
private void deleteFile(File file) {
if (file.exists() && !file.delete()) {
throw new MessageException(String.format(
"Fail to delete file %s. Please check that no SonarQube process is alive", file));
}
}
}
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