1 /* Licensed to the Apache Software Foundation (ASF) under one or more 2 * contributor license agreements. See the NOTICE file distributed with 3 * this work for additional information regarding copyright ownership. 4 * The ASF licenses this file to You under the Apache License, Version 2.0 5 * (the "License"); you may not use this file except in compliance with 6 * the License. You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package org.apache.harmony.nio.internal; 18 19 import java.io.IOException; 20 import java.nio.channels.ClosedChannelException; 21 import java.nio.channels.FileChannel; 22 import java.nio.channels.FileLock; 23 24 /** 25 * The concrete implementation of an NIO file lock object. 26 */ 27 final class FileLockImpl extends FileLock { 28 29 // Remembers if this lock has been released via the API. 30 private boolean isReleased = false; 31 32 /** 33 * Constructs a new file lock object with the given parameters. 34 * 35 * @param channel 36 * the file channel hosting the lock. 37 * @param position 38 * the start position of the lock, in bytes 39 * @param size 40 * the length of the lock, in bytes 41 * @param shared 42 * whether this lock is shared (true) or exclusive (false) 43 */ 44 public FileLockImpl(FileChannel channel, long position, long size, boolean shared) { 45 super(channel, position, size, shared); 46 } 47 48 /** 49 * Tests to see if the lock is valid. A lock can be invalidated if the 50 * channel it is acquired on is closed or if it is released. (non-Javadoc) 51 * 52 * @see java.nio.channels.FileLock#isValid() 53 */ 54 @Override 55 public boolean isValid() { 56 return !isReleased && channel().isOpen(); 57 } 58 59 /** 60 * Releases the file lock on the channel that acquired it. Releasing an 61 * invalid lock has no effect. 62 * 63 * @see java.nio.channels.FileLock#release() 64 */ 65 @Override 66 public void release() throws IOException { 67 if (!channel().isOpen()) { 68 throw new ClosedChannelException(); 69 } 70 71 if (!isReleased) { 72 ((FileChannelImpl) channel()).release(this); 73 isReleased = true; 74 } 75 } 76 } 77
