com.continuent.tungsten.replicator.util
Class AtomicCounter

java.lang.Object
  com.continuent.tungsten.replicator.util.AtomicCounter

public class AtomicCounter
extends java.lang.Object

Defines a simple "atomic counter" that allows clients to increment the encapsulated sequence number and wait synchronously until particular values are reached. This class is thread-safe.

Version:

1.0

Author:

Teemu Ollakka, Robert Hodges

Constructor Summary

AtomicCounter(long seqno)
Creates a new Sequencer object with a starting value.

Method Summary

long	decrAndGetSeqno() Decrement seqno and notify waiters, then return value.
long	getSeqno() Get value of current seqno.
long	incrAndGetSeqno() Increment seqno and notify waiters, then return value.
void	setSeqno(long seqno) Sets values of current seqno.
java.lang.String	toString() Print a string representation of the value.
void	waitSeqnoGreaterEqual(long waitSeqno) Wait until seqno is greater than or equal to the desired value.
boolean	waitSeqnoGreaterEqual(long waitSeqno, long millis) Wait until seqno is greater than or equal to the desired value *or* we exceed the timeout.
void	waitSeqnoLessEqual(long waitSeqno) Wait until seqno is less than or equal to the desired value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

AtomicCounter

public AtomicCounter(long seqno)

Creates a new Sequencer object with a starting value.

Parameters:

seqno - Initial sequence number

Method Detail

getSeqno

public long getSeqno()

Get value of current seqno.

setSeqno

public void setSeqno(long seqno)

Sets values of current seqno. Value can only be set upward.

incrAndGetSeqno

public long incrAndGetSeqno()

Increment seqno and notify waiters, then return value.

decrAndGetSeqno

public long decrAndGetSeqno()

Decrement seqno and notify waiters, then return value.

waitSeqnoGreaterEqual

public void waitSeqnoGreaterEqual(long waitSeqno)
                           throws java.lang.InterruptedException

Wait until seqno is greater than or equal to the desired value.

Parameters:

waitSeqno - Sequence number to wait for

Throws:

java.lang.InterruptedException - if somebody cancels the wait

waitSeqnoGreaterEqual

public boolean waitSeqnoGreaterEqual(long waitSeqno,
                                     long millis)
                              throws java.lang.InterruptedException

Wait until seqno is greater than or equal to the desired value *or* we exceed the timeout.

Parameters:

waitSeqno - Sequence number to wait for

millis - Number of milliseconds to wait

Returns:

True if wait was successful, otherwise false

Throws:

java.lang.InterruptedException - if somebody cancels the wait

waitSeqnoLessEqual

public void waitSeqnoLessEqual(long waitSeqno)
                        throws java.lang.InterruptedException

Wait until seqno is less than or equal to the desired value.

Parameters:

waitSeqno - Sequence number to wait for

Throws:

java.lang.InterruptedException - if somebody cancels the wait

toString

public java.lang.String toString()

Print a string representation of the value.

Overrides:

toString in class java.lang.Object