lol

src/zutil/OneAppFile.java

@@ -0,0 +1,99 @@
+package zutil;
+
+import java.io.File;
+import java.io.RandomAccessFile;
+import java.nio.channels.FileChannel;
+import java.nio.channels.FileLock;
+import java.nio.channels.OverlappingFileLockException;
+
+/**
+ * This class checks if the application is already running
+ * by Locking a file
+ * 
+ * @author Ziver Koc
+ */
+public class OneAppFile implements OneApp{
+	private File file;
+	private FileChannel channel;
+	private FileLock lock;
+
+	/**
+	 * Creates a OneApp class
+	 * 
+	 * @param filename The name of the file to be locked
+	 */
+	public OneAppFile(String filename){
+		this.file = new File(System.getProperty("user.home"), filename);
+	}
+
+	/**
+	 * Checks if the file have already bean locked
+	 * 
+	 * @return True if the file is locked else false
+	 */
+	public boolean check() {
+		boolean tmp = lockApp();
+		closeLock();
+		return !tmp;
+	}
+
+	/**
+	 * Locks the file
+	 *  
+	 * @return False if there are a error else true
+	 */
+	public boolean lockApp() {	    
+		try {
+			channel = new RandomAccessFile(file, "rw").getChannel();
+
+			try {
+				lock = channel.tryLock();
+			}
+			catch (OverlappingFileLockException e) {
+				// already locked
+				closeLock();
+				return false;
+			}
+
+			if (lock == null) {
+				closeLock();
+				return false;
+			}
+
+			Runtime.getRuntime().addShutdownHook(new Thread() {
+				// destroy the lock when the JVM is closing
+				public void run() {
+					closeLock();
+					deleteFile();
+				}
+			});
+			return true;
+		}
+		catch (Exception e) {
+			closeLock();
+			return false;
+		}
+	}
+
+	private void closeLock() {
+		try { 
+			lock.release(); 
+			channel.close();
+		}
+		catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+
+	private void deleteFile() {
+		try { 
+			file.delete(); 
+		}
+		catch (Exception e) {
+			e.printStackTrace();
+		}
+	}
+}
+
+
+