[Exist-commits] eXist-1.0/src/org/exist/util ReentrantReadWriteLock.java,1.5,1.6 MultiReadReentrantLock.java,1.2,1.3 Lock.java,1.4,1.5

[Wolfgang M. M. <wol...@us...>]

Update of /cvsroot/exist/eXist-1.0/src/org/exist/util
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv8244/src/org/exist/util

Modified Files:
	ReentrantReadWriteLock.java MultiReadReentrantLock.java 
	Lock.java 
Log Message:
Revised collection locking to fix various concurrency errors. It is now the responsibility of the 
caller to lock/unlock a collection. A collection can be retrieved and locked via the new 
openCollection() method provided by DBBroker. After reading/modifying the collection, it should be 
unlocked by calling Collection.release.

The local XML:DB implementation and the XMLRPC interface have been changed to reflect the new
collection locking rules.

Index: Lock.java
===================================================================
RCS file: /cvsroot/exist/eXist-1.0/src/org/exist/util/Lock.java,v
retrieving revision 1.4
retrieving revision 1.5
diff -C2 -d -r1.4 -r1.5
*** Lock.java	2 Jun 2004 11:34:34 -0000	1.4
--- Lock.java	3 Aug 2004 15:25:57 -0000	1.5
***************
*** 27,33 ****
  	public final static int READ_LOCK = 0;
  	public final static int WRITE_LOCK = 1;
  	
  	/**
! 	 * Attempt to acquire a lock for read.
  	 * 
  	 * @return
--- 27,34 ----
  	public final static int READ_LOCK = 0;
  	public final static int WRITE_LOCK = 1;
+ 	public final static int NO_LOCK = -1;
  	
  	/**
! 	 * Acquire a lock for read.
  	 * 
  	 * @return
***************
*** 37,41 ****
      
      /**
!      * Attempt to acquire a lock for read or write.
       * mode is one of {@link #READ_LOCK} or
       * {@link #WRITE_LOCK}.
--- 38,42 ----
      
      /**
!      * Acquire a lock for read or write.
       * mode is one of {@link #READ_LOCK} or
       * {@link #WRITE_LOCK}.
***************
*** 48,51 ****
--- 49,62 ----
  	
  	/**
+ 	 * Attempt to acquire a lock for read or write. This method
+ 	 * will fail immediately if the lock cannot be acquired.
+ 	 *  
+ 	 * @param mode
+ 	 * @return
+ 	 * @throws LockException
+ 	 */
+ 	public boolean attempt( int mode );
+ 	
+ 	/**
  	 * Release a lock. This method assumes that the
  	 * lock is a read lock.

Index: MultiReadReentrantLock.java
===================================================================
RCS file: /cvsroot/exist/eXist-1.0/src/org/exist/util/MultiReadReentrantLock.java,v
retrieving revision 1.2
retrieving revision 1.3
diff -C2 -d -r1.2 -r1.3
*** MultiReadReentrantLock.java	8 Jun 2004 08:16:14 -0000	1.2
--- MultiReadReentrantLock.java	3 Aug 2004 15:25:57 -0000	1.3
***************
*** 93,96 ****
--- 93,103 ----
      }
  
+     /* (non-Javadoc)
+ 	 * @see org.exist.util.Lock#attempt(int)
+ 	 */
+ 	public boolean attempt(int mode) {
+ 		throw new RuntimeException("Not implemented");
+ 	}
+ 	
      /**
       * Issue a read lock if there is no outstanding write lock or threads

Index: ReentrantReadWriteLock.java
===================================================================
RCS file: /cvsroot/exist/eXist-1.0/src/org/exist/util/ReentrantReadWriteLock.java,v
retrieving revision 1.5
retrieving revision 1.6
diff -C2 -d -r1.5 -r1.6
*** ReentrantReadWriteLock.java	8 Jun 2004 08:16:14 -0000	1.5
--- ReentrantReadWriteLock.java	3 Aug 2004 15:25:57 -0000	1.6
***************
*** 99,102 ****
--- 99,122 ----
  	}
  
+ 	public boolean attempt(int mode) {
+ 		Thread caller = Thread.currentThread();
+ 		synchronized (this) {
+ 			if (caller == owner_) {
+ 				++holds_;
+ 				mode_ = mode;
+ //				System.out.println("thread " + caller.getName() + " acquired lock on " + id_ +
+ //					"; locks held = " + holds_);
+ 				return true;
+ 			} else if (owner_ == null) {
+ 				owner_ = caller;
+ 				holds_ = 1;
+ 				mode_ = mode;
+ //				System.out.println("thread " + caller.getName() + " acquired lock on " + id_);
+ 				return true;
+ 			} else {
+ 				return false;
+ 			}
+ 		}
+ 	}
  	
      /* (non-Javadoc)