Package net.sourceforge.jtds.jdbc
Class Semaphore
- java.lang.Object
-
- net.sourceforge.jtds.jdbc.Semaphore
-
public class Semaphore extends java.lang.Object
Simple semaphore class used to serialize access requests over the network connection. Based on the code originally written by Doug Lea. Once JDK 1.5 is the standard this class can be replaced by thejava.util.concurrent.Sempahore
class.- Version:
- $Id: Semaphore.java,v 1.1 2004-12-20 15:51:17 alin_sinpalean Exp $
- Author:
- Mike Hutchinson
-
-
Field Summary
Fields Modifier and Type Field Description protected long
permits
Current number of available permits.
-
Constructor Summary
Constructors Constructor Description Semaphore(long initialPermits)
Create a Semaphore with the given initial number of permits.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
acquire()
Wait until a permit is available, and take one.boolean
attempt(long msecs)
Wait at most msecs millisconds for a permit.long
permits()
Return the current number of available permits.void
release()
Release a permit.void
release(long n)
Release N permits.
-
-
-
Constructor Detail
-
Semaphore
public Semaphore(long initialPermits)
Create a Semaphore with the given initial number of permits. Using a seed of one makes the semaphore act as a mutual exclusion lock. Negative seeds are also allowed, in which case no acquires will proceed until the number of releases has pushed the number of permits past 0.
-
-
Method Detail
-
acquire
public void acquire() throws java.lang.InterruptedException
Wait until a permit is available, and take one.- Throws:
java.lang.InterruptedException
-
attempt
public boolean attempt(long msecs) throws java.lang.InterruptedException
Wait at most msecs millisconds for a permit.- Throws:
java.lang.InterruptedException
-
release
public void release()
Release a permit.
-
release
public void release(long n)
Release N permits.release(n)
is equivalent in effect to:for (int i = 0; i < n; ++i) release();
But may be more efficient in some semaphore implementations.- Throws:
java.lang.IllegalArgumentException
- if n is negative
-
permits
public long permits()
Return the current number of available permits. Returns an accurate, but possibly unstable value, that may change immediately after returning.
-
-