Coverage Report

Coverage Report - net.wotonomy.foundation.NSMultiReaderLock

Classes in this File

2.071

 /*
 Wotonomy: OpenStep design patterns for pure Java applications.
 Copyright (C) 2002 Israfil consulting Services Corporation
 
 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.
 
 This library 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
 Lesser General Public License for more details.
 
 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, see http://www.gnu.org
 
 $Id: NSMultiReaderLock.java 893 2006-02-16 13:22:23 +0000 (Thu, 16 Feb 2006) cgruber $
 
 */
 
 package net.wotonomy.foundation;
 
 import EDU.oswego.cs.dl.util.concurrent.ReentrantWriterPreferenceReadWriteLock;
 
 /**
 * A Read-Write lock that allows unlimited number of calling threads to
 * acquire read locks, but only one thread to acquire a write lock.  It 
 * is also reentrant, allowing each thread to re-acquire it's lock 
 * recursively.  For that reason it is somewhat slower, as there is a 
 * hash lookup when attempting to acquire and release reader locks. Of 
 * course a writer lock is quite a bit slower than a reader lock.  A 
 * write lock is mutally exclusive with read locks, though a thread 
 * that has obtained a read-lock may be promoted to a write lock and 
 * vice versa when conditions permit.
 *
 * @author cgruber@israfil.net
 * @author $Author: cgruber $
 * @version $Revision: 893 $
 */
 public class NSMultiReaderLock extends ReentrantWriterPreferenceReadWriteLock implements NSLocking {
 
     NSMutableDictionary _readerSuspended = new NSMutableDictionary();
 
     public NSMultiReaderLock() {
     }
 
     public void lockForReading() {
        try {
             readerLock_.acquire();
         } catch (InterruptedException interruptedexception) {
             // Null behavior, as notify() is already called
             // by acquire();            
             // We may want to log here.  
         }
     }
 
     public void unlockForReading() {
         readerLock_.release();
     }
 
     public void lock() {
         lockForWriting();
     }
 
     public void lockForWriting() {
        try {
             writerLock_.acquire();
         } catch (InterruptedException interruptedexception) {
             // Null behavior, as notify() is already called
             // by acquire();            
             // We may want to log here.  
         }
     }
 
     public void unlock() {
         unlockForWriting();
     }
 
     public void unlockForWriting() {
         writerLock_.release();
     }
 
     /** @see com.webobjects.foundation.NSMultiReaderLock#suspendReaderLock() */
     public void suspendReaderLocks() {
         Thread thisThread = Thread.currentThread();
         Integer suspendedReaders = (Integer)_readerSuspended.get(thisThread);
         if (suspendedReaders != null && suspendedReaders.intValue() > 0) return;
         // logic is to override startRead / endRead and ensure that the suspension
         // isn't improperly stopped.
                 throw new UnsupportedOperationException("Not Yet Implemented");
     }
 
     /** @see com.webobjects.foundation.NSMultiReaderLock#retrieveReaderLock() */
     public void retrieveReaderLocks() {
         Thread thisThread = Thread.currentThread();
         Integer suspendedReaders = (Integer)_readerSuspended.get(thisThread);
         if (suspendedReaders != null && suspendedReaders.intValue() > 0) return;
         // logic is to override startRead / endRead and ensure that the suspension
         // isn't improperly stopped.
         throw new UnsupportedOperationException("Not Yet Implemented");
     }
 
     public boolean tryLockForWriting() {
         try {
             return writerLock_.attempt(0);
         } catch (InterruptedException interruptedexception) {
             // notify() is already called by attempt();
             // We may want to log here.  
             return false;
         }
     }
 
     public boolean tryLockForReading() {
         try {
             return readerLock_.attempt(0);
         } catch (InterruptedException interruptedexception) {
             // notify() is already called by attempt();
             // We may want to log here.  
             return false;
         }
     }
 
     public String toString() {
                 throw new UnsupportedOperationException("Not Yet Implemented");
     }
 
     protected String _padString(long l, int i) {
                 throw new UnsupportedOperationException("Not Yet Implemented");
     }
 
     protected String _padString(String s, int i, boolean flag) {
                 throw new UnsupportedOperationException("Not Yet Implemented");
     }
 
 
 }
 /*
  * $Log$
  * Revision 1.2  2006/02/16 13:15:00  cgruber
  * Check in all sources in eclipse-friendly maven-enabled packages.
  *
  * Revision 1.2  2003/08/06 23:07:52  chochos
  * general code cleanup (mostly, removing unused imports)
  *
  * Revision 1.1  2002/07/14 21:56:16  mpowers
  * Contributions from cgruber.
  *
  * Revision 1.2  2002/06/26 00:40:22  cgruber
  * Add implementation, using ReentrantWriterPreferenceReadWriteLock
  * as a base.
  * 
  * suspendReaderLocks and retreiveReaderLocks is the one
  * that's likeliest to be a pain.
  *
  * Revision 1.1  2002/06/25 07:52:57  cgruber
  * Add quite a few abstract classes, interfaces, and classes.  All API consistent with WebObjects, but with no implementation, nor any private or package access members from the original.
  *
  */

1		/*
2		Wotonomy: OpenStep design patterns for pure Java applications.
3		Copyright (C) 2002 Israfil consulting Services Corporation
4
5		This library is free software; you can redistribute it and/or
6		modify it under the terms of the GNU Lesser General Public
7		License as published by the Free Software Foundation; either
8		version 2.1 of the License, or (at your option) any later version.
9
10		This library is distributed in the hope that it will be useful,
11		but WITHOUT ANY WARRANTY; without even the implied warranty of
12		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13		Lesser General Public License for more details.
14
15		You should have received a copy of the GNU Lesser General Public
16		License along with this library; if not, see http://www.gnu.org
17
18		$Id: NSMultiReaderLock.java 893 2006-02-16 13:22:23 +0000 (Thu, 16 Feb 2006) cgruber $
19
20		*/
21
22		package net.wotonomy.foundation;
23
24		import EDU.oswego.cs.dl.util.concurrent.ReentrantWriterPreferenceReadWriteLock;
25
26		/**
27		* A Read-Write lock that allows unlimited number of calling threads to
28		* acquire read locks, but only one thread to acquire a write lock. It
29		* is also reentrant, allowing each thread to re-acquire it's lock
30		* recursively. For that reason it is somewhat slower, as there is a
31		* hash lookup when attempting to acquire and release reader locks. Of
32		* course a writer lock is quite a bit slower than a reader lock. A
33		* write lock is mutally exclusive with read locks, though a thread
34		* that has obtained a read-lock may be promoted to a write lock and
35		* vice versa when conditions permit.
36		*
37		* @author cgruber@israfil.net
38		* @author $Author: cgruber $
39		* @version $Revision: 893 $
40		*/
41		public class NSMultiReaderLock extends ReentrantWriterPreferenceReadWriteLock implements NSLocking {
42
43	0	NSMutableDictionary _readerSuspended = new NSMutableDictionary();
44
45	0	public NSMultiReaderLock() {
46	0	}
47
48		public void lockForReading() {
49		try {
50	0	readerLock_.acquire();
51	0	} catch (InterruptedException interruptedexception) {
52		// Null behavior, as notify() is already called
53		// by acquire();
54		// We may want to log here.
55	0	}
56	0	}
57
58		public void unlockForReading() {
59	0	readerLock_.release();
60	0	}
61
62		public void lock() {
63	0	lockForWriting();
64	0	}
65
66		public void lockForWriting() {
67		try {
68	0	writerLock_.acquire();
69	0	} catch (InterruptedException interruptedexception) {
70		// Null behavior, as notify() is already called
71		// by acquire();
72		// We may want to log here.
73	0	}
74	0	}
75
76		public void unlock() {
77	0	unlockForWriting();
78	0	}
79
80		public void unlockForWriting() {
81	0	writerLock_.release();
82	0	}
83
84		/** @see com.webobjects.foundation.NSMultiReaderLock#suspendReaderLock() */
85		public void suspendReaderLocks() {
86	0	Thread thisThread = Thread.currentThread();
87	0	Integer suspendedReaders = (Integer)_readerSuspended.get(thisThread);
88	0	if (suspendedReaders != null && suspendedReaders.intValue() > 0) return;
89		// logic is to override startRead / endRead and ensure that the suspension
90		// isn't improperly stopped.
91	0	throw new UnsupportedOperationException("Not Yet Implemented");
92		}
93
94		/** @see com.webobjects.foundation.NSMultiReaderLock#retrieveReaderLock() */
95		public void retrieveReaderLocks() {
96	0	Thread thisThread = Thread.currentThread();
97	0	Integer suspendedReaders = (Integer)_readerSuspended.get(thisThread);
98	0	if (suspendedReaders != null && suspendedReaders.intValue() > 0) return;
99		// logic is to override startRead / endRead and ensure that the suspension
100		// isn't improperly stopped.
101	0	throw new UnsupportedOperationException("Not Yet Implemented");
102		}
103
104		public boolean tryLockForWriting() {
105		try {
106	0	return writerLock_.attempt(0);
107	0	} catch (InterruptedException interruptedexception) {
108		// notify() is already called by attempt();
109		// We may want to log here.
110	0	return false;
111		}
112		}
113
114		public boolean tryLockForReading() {
115		try {
116	0	return readerLock_.attempt(0);
117	0	} catch (InterruptedException interruptedexception) {
118		// notify() is already called by attempt();
119		// We may want to log here.
120	0	return false;
121		}
122		}
123
124		public String toString() {
125	0	throw new UnsupportedOperationException("Not Yet Implemented");
126		}
127
128		protected String _padString(long l, int i) {
129	0	throw new UnsupportedOperationException("Not Yet Implemented");
130		}
131
132		protected String _padString(String s, int i, boolean flag) {
133	0	throw new UnsupportedOperationException("Not Yet Implemented");
134		}
135
136
137		}
138		/*
139		* $Log$
140		* Revision 1.2 2006/02/16 13:15:00 cgruber
141		* Check in all sources in eclipse-friendly maven-enabled packages.
142		*
143		* Revision 1.2 2003/08/06 23:07:52 chochos
144		* general code cleanup (mostly, removing unused imports)
145		*
146		* Revision 1.1 2002/07/14 21:56:16 mpowers
147		* Contributions from cgruber.
148		*
149		* Revision 1.2 2002/06/26 00:40:22 cgruber
150		* Add implementation, using ReentrantWriterPreferenceReadWriteLock
151		* as a base.
152		*
153		* suspendReaderLocks and retreiveReaderLocks is the one
154		* that's likeliest to be a pain.
155		*
156		* Revision 1.1 2002/06/25 07:52:57 cgruber
157		* Add quite a few abstract classes, interfaces, and classes. All API consistent with WebObjects, but with no implementation, nor any private or package access members from the original.
158		*
159		*/