com.tangosol.util

Class ThreadGateLite<R>

java.lang.Object

com.tangosol.util.ThreadGateLite<R>

All Implemented Interfaces:

com.oracle.common.util.Gate<R>

public final class ThreadGateLite<R>
extends Object
implements Gate<R>

ThreadGateLite is a Gate implementation built around the ReentrantReadWriteLock.

Since:

Coherence 3.7

Author:

coh 2010.08.09

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	ThreadGateLite.Bar Bar represents the state of the bars placed on this gate.

Field Summary

Fields

Modifier and Type	Field and Description
protected com.oracle.common.util.Sentry<R>	f_exitSentry Sentry to return from enter() that will exit() when the sentry is closed.
protected com.oracle.common.util.Sentry<R>	f_openSentry Sentry to return from close() that will open() when the sentry is closed.

Constructor Summary

Constructors

Constructor and Description
ThreadGateLite() Default constructor.
ThreadGateLite(R resource) Construct a ThreadGateLite protected the specified resource.

Method Summary

Modifier and Type	Method and Description
protected long	adjustWaitTime(long cMillis, long ldtStart) Calculate the time remaining from the total time allotted for an operation.
boolean	barEntry(long cMillis) Bar entry to the thread gate by other threads, but do not wait for the gate to close.
com.oracle.common.util.Sentry<R>	close() Wait to close the gate.
boolean	close(long cMillis) Close the gate.
com.oracle.common.util.Sentry<R>	enter() Wait to enter the gate.
boolean	enter(long cMillis) Enter the gate.
void	exit() Exit the gate.
boolean	isClosed() Determine if any thread has closed the gate and continues to hold exclusive access.
boolean	isClosedByCurrentThread() Determine if the calling thread has closed the gate and continues to hold exclusive access.
boolean	isEnteredByCurrentThread() Determines if the current thread has entered the gate and not yet exited.
void	open() Re-open the closed gate.
String	toString()
protected long	waitForOpen(ThreadGateLite.Bar bar, long cMillis) Wait for notification that the bar has been lifted completely, i.e. all re-entrant barEntry calls were matched.

Methods inherited from class java.lang.Object

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

Field Detail

f_exitSentry

protected final com.oracle.common.util.Sentry<R> f_exitSentry

Sentry to return from enter() that will exit() when the sentry is closed.

f_openSentry

protected final com.oracle.common.util.Sentry<R> f_openSentry

Sentry to return from close() that will open() when the sentry is closed.

Constructor Detail

ThreadGateLite

public ThreadGateLite()

Default constructor.

ThreadGateLite

public ThreadGateLite(R resource)

Construct a ThreadGateLite protected the specified resource.

Parameters:

resource - the resource

Method Detail

close

public com.oracle.common.util.Sentry<R> close()

Description copied from interface: com.oracle.common.util.Gate

Wait to close the gate.

Specified by:

close in interface com.oracle.common.util.Gate<R>

Returns:

an AutoCloseable which can be used with a try-with-resource block to perform the corresponding Gate.open().

close

public boolean close(long cMillis)

Close the gate. A thread uses this method to obtain exclusive access to the resource represented by the gate. Each invocation of this method must ultimately have a corresponding invocation of the Gate.open() method.

Specified by:

close in interface com.oracle.common.util.Gate<R>

Parameters:

cMillis - maximum number of milliseconds to wait; pass -1 to wait indefinitely or 0 to return immediately

Returns:

true iff entry into the gate was successfully closed by the calling thread and no other threads remain in the gate

enter

public com.oracle.common.util.Sentry<R> enter()

Description copied from interface: com.oracle.common.util.Gate

Wait to enter the gate.

Specified by:

enter in interface com.oracle.common.util.Gate<R>

Returns:

an AutoCloseable which can be used with a try-with-resource block to perform the corresponding Gate.exit().

enter

public boolean enter(long cMillis)

Enter the gate. A thread uses this method to obtain non-exclusive access to the resource represented by the gate. Each invocation of this method must ultimately have a corresponding invocation of the Gate.exit() method.

Specified by:

enter in interface com.oracle.common.util.Gate<R>

Parameters:

cMillis - maximum number of milliseconds to wait; pass -1 to wait indefinitely or 0 to return immediately

Returns:

true iff the calling thread successfully entered the gate

exit

public void exit()

Exit the gate. A thread must invoke this method corresponding to each invocation of the Gate.enter() method.

Specified by:

exit in interface com.oracle.common.util.Gate<R>

isClosedByCurrentThread

public boolean isClosedByCurrentThread()

Determine if the calling thread has closed the gate and continues to hold exclusive access.

Specified by:

isClosedByCurrentThread in interface com.oracle.common.util.Gate<R>

Returns:

true iff the calling thread holds exclusive access to the gate

isClosed

public boolean isClosed()

Determine if any thread has closed the gate and continues to hold exclusive access.

Specified by:

isClosed in interface com.oracle.common.util.Gate<R>

Returns:

true iff there is a thread that holds exclusive access to the gate

isEnteredByCurrentThread

public boolean isEnteredByCurrentThread()

Determines if the current thread has entered the gate and not yet exited.

Specified by:

isEnteredByCurrentThread in interface com.oracle.common.util.Gate<R>

Returns:

true if the current thread has entered the gate

open

public void open()

Re-open the closed gate. This method can be called only if the calling thread successfully closed the gate.

Specified by:

open in interface com.oracle.common.util.Gate<R>

barEntry

public boolean barEntry(long cMillis)

Bar entry to the thread gate by other threads, but do not wait for the gate to close. When all other threads have exited, the status of the thread gate will be closeable by the thread which barred entry. Threads that have already entered the gate at the time of this method call should be allowed to succeed in additional #enter calls.

Each successful invocation of this method must ultimately have a corresponding invocation of the open method (assuming the thread gate is not destroyed) even if the calling thread does not subsequently close the gate.

 gate.barEntry(-1);
 try
     {
     // processing that does not require the gate to be closed
     // ...
     }
 finally
     {
     gate.close(-1);
     try
         {
         // processing that does require the gate to be closed
         // ...
         }
     finally
         {
         gate.open(); // matches gate.close()
         }
     gate.open(); // matches gate.barEntry()
     }
 

Specified by:

barEntry in interface com.oracle.common.util.Gate<R>

Parameters:

cMillis - maximum number of milliseconds to wait; pass -1 for forever or 0 for no wait

Returns:

true iff entry into the thread gate was successfully barred by the calling thread

toString

public String toString()

Overrides:

toString in class Object

waitForOpen

protected long waitForOpen(ThreadGateLite.Bar bar,
                           long cMillis)

Wait for notification that the bar has been lifted completely, i.e. all re-entrant barEntry calls were matched. See open().

Parameters:

bar - the bar that needs to be lifted for this thread to proceed (cannot be null)

cMillis - time to wait or -1 for unlimited wait

Returns:

the remaining wait time, or 0 if the wait time has expired

adjustWaitTime

protected long adjustWaitTime(long cMillis,
                              long ldtStart)

Calculate the time remaining from the total time allotted for an operation.

Parameters:

cMillis - the total time allotted for an operation

ldtStart - the start of the time interval that have passed

Returns:

the remaining wait time in milliseconds. The value may be positive, zero for no time left or -1 for indefinite wait.