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54 lines
1.1 KiB
54 lines
1.1 KiB
package mightypork.utils.files;
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import java.io.File;
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import java.io.IOException;
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import java.io.RandomAccessFile;
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import java.nio.channels.FileLock;
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/**
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* Instance lock (avoid running twice)
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*
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* @author Ondřej Hruška (MightyPork)
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*/
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public class InstanceLock {
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@SuppressWarnings("resource")
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public static boolean onFile(final File lockFile)
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{
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try {
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lockFile.getParentFile().mkdirs();
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final RandomAccessFile randomAccessFile = new RandomAccessFile(lockFile, "rw");
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final FileLock fileLock = randomAccessFile.getChannel().tryLock();
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if (fileLock != null) {
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Runtime.getRuntime().addShutdownHook(new Thread() {
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@Override
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public void run()
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{
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try {
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fileLock.release();
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randomAccessFile.close();
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if (!lockFile.delete()) throw new IOException();
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} catch (final Throwable t) {
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System.err.println("Unable to remove lock file.");
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t.printStackTrace();
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}
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}
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});
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return true;
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}
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return false;
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} catch (final IOException e) {
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System.err.println("IO error while obtaining lock.");
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e.printStackTrace();
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return false;
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}
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}
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}
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