| Classes in this File | Line Coverage | Branch Coverage | Complexity | ||||
| Lock |
|
| 3.0;3 |
| 1 | /* | |
| 2 | * Copyright (C) The Apache Software Foundation. All rights reserved. | |
| 3 | * | |
| 4 | * This software is published under the terms of the Apache Software License | |
| 5 | * version 1.1, a copy of which has been included with this distribution in | |
| 6 | * the LICENSE file. | |
| 7 | * | |
| 8 | * $Id: Lock.java 155459 2005-02-26 13:24:44Z dirkv $ | |
| 9 | */ | |
| 10 | package org.apache.commons.messenger; | |
| 11 | ||
| 12 | import javax.jms.JMSException; | |
| 13 | ||
| 14 | /** <p><code>Lock</code> is a simple lock. | |
| 15 | * | |
| 16 | * @author <a href="mailto:jstrachan@apache.org">James Strachan</a> | |
| 17 | * @version $Revision: 155459 $ | |
| 18 | */ | |
| 19 | 0 | public class Lock { |
| 20 | ||
| 21 | private Thread owner; | |
| 22 | private int count; | |
| 23 | ||
| 24 | /** | |
| 25 | * Acquires the lock, blocking until the lock can be acquired | |
| 26 | * @throws InterruptedException | |
| 27 | */ | |
| 28 | public void acquire() { | |
| 29 | 0 | Thread caller = Thread.currentThread(); |
| 30 | 0 | synchronized (this) { |
| 31 | 0 | if (caller == owner) { |
| 32 | 0 | count++; |
| 33 | } | |
| 34 | else { | |
| 35 | 0 | while (owner != null) { |
| 36 | try { | |
| 37 | 0 | wait(); |
| 38 | } | |
| 39 | 0 | catch (InterruptedException ex) { |
| 40 | // ignore | |
| 41 | 0 | } |
| 42 | } | |
| 43 | 0 | owner = caller; |
| 44 | 0 | count = 1; |
| 45 | ||
| 46 | // System.out.println("Lock: " + this + " acquired by + "+ caller ); | |
| 47 | // new Exception().printStackTrace(); | |
| 48 | } | |
| 49 | 0 | } |
| 50 | 0 | } |
| 51 | ||
| 52 | /** | |
| 53 | * Release the lock. | |
| 54 | **/ | |
| 55 | public synchronized void release() throws JMSException { | |
| 56 | 0 | if (Thread.currentThread() != owner) { |
| 57 | 0 | throw new JMSException("Cannot release lock - not the current owner"); |
| 58 | } | |
| 59 | else { | |
| 60 | 0 | if (--count == 0) { |
| 61 | // System.out.println("Lock: " + this + " released by + "+ owner ); | |
| 62 | // new Exception().printStackTrace(); | |
| 63 | ||
| 64 | 0 | owner = null; |
| 65 | ||
| 66 | 0 | notify(); |
| 67 | } | |
| 68 | } | |
| 69 | 0 | } |
| 70 | ||
| 71 | /** | |
| 72 | * @return | |
| 73 | */ | |
| 74 | public synchronized boolean hasLock() { | |
| 75 | 0 | return Thread.currentThread() == owner; |
| 76 | } | |
| 77 | } |