lockfile added

diff --git a/source/mir/util/LockFile.java b/source/mir/util/LockFile.java
new file mode 100644 (file)
index 0000000..d12f825
--- /dev/null
+++ b/source/mir/util/LockFile.java
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2001, 2002 The Mir-coders group
+ *
+ * This file is part of Mir.
+ *
+ * Mir is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * Mir 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Mir; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * In addition, as a special exception, The Mir-coders gives permission to link
+ * the code of this program with  any library licensed under the Apache Software License,
+ * The Sun (tm) Java Advanced Imaging library (JAI), The Sun JIMI library
+ * (or with modified versions of the above that use the same license as the above),
+ * and distribute linked combinations including the two.  You must obey the
+ * GNU General Public License in all respects for all of the code used other than
+ * the above mentioned libraries.  If you modify this file, you may extend this
+ * exception to your version of the file, but you are not obligated to do so.
+ * If you do not wish to do so, delete this exception statement from your version.
+ */
+package mir.util;
+
+import java.io.File;
+import java.io.IOException;
+
+/**
+ * Class to do locking by way of a file:
+ * existence of the file means the lock is enabled.
+ */
+public class LockFile {
+  private File file;
+
+  /**
+   * Creates an instance based on a filename
+   */
+  public LockFile(String aFileName) {
+    file = new File(aFileName);
+  }
+
+  public LockFile(File aFile) {
+    file = new File(aFile.getAbsolutePath());
+  }
+
+  /**
+   * Tries to enable the lock. Returns <code>true</code> on success.
+   */
+  public boolean lock() throws IOException {
+    if (file.createNewFile()) {
+      file.deleteOnExit();
+      return true;
+    }
+    else {
+      return false;
+    }
+  }
+
+  /**
+   * Returns <code>true</code> if locked, either by external parties
+   * or by this object.
+   */
+  public boolean isLocked() {
+    return file.exists();
+  }
+
+  /**
+   * Removes the lock, wether it was enabled by this object or by
+   * an external party.
+   */
+  public void unlock() {
+    file.delete();
+  }
+}