Package io.debezium.util

Class VariableLatch

java.lang.Object

io.debezium.util.VariableLatch

@ThreadSafe
public class VariableLatch
extends Object

A latch that works similarly to CountDownLatch except that it can also increase the count dynamically.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static final class	VariableLatch.Sync	Synchronization control For CountDownLatch.

Field Summary

Fields

Modifier and Type	Field	Description
private final VariableLatch.Sync	sync

Constructor Summary

Constructors

Constructor	Description
VariableLatch(int count)	Constructs a CountDownLatch initialized with the given count.

Method Summary

Modifier and Type	Method	Description
void	await()	Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted.
boolean	await(long timeout, TimeUnit unit)	Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted, or the specified waiting time elapses.
void	countDown()	Decrements the count of the latch, releasing all waiting threads if the count reaches zero.
void	countDown(int count)	Decrements the count of the latch, releasing all waiting threads if the count reaches zero.
void	countUp()	Increments the count of the latch by one.
void	countUp(int count)	Increments the count of the latch by a positive number.
static VariableLatch	create()	Create a new variable latch.
static VariableLatch	create(int initialValue)	Create a new variable latch.
long	getCount()	Returns the current count.
String	toString()	Returns a string identifying this latch, as well as its state.

Methods inherited from class java.lang.Object

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

Field Details

sync

private final VariableLatch.Sync sync

Constructor Details

VariableLatch

public VariableLatch(int count)

Constructs a CountDownLatch initialized with the given count.

Parameters:

count - the number of times countDown() must be invoked before threads can pass through await()

Throws:

IllegalArgumentException - if count is negative

Method Details

create

public static VariableLatch create()

Create a new variable latch.

Returns:

the variable latch; never null

create

public static VariableLatch create(int initialValue)

Create a new variable latch.

Parameters:

initialValue - the initial number of latches

Returns:

the variable latch; never null

await

public void await()
           throws InterruptedException

Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted.

If the current count is zero then this method returns immediately.

If the current count is greater than zero then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of two things happen:

• The count reaches zero due to invocations of the countDown() method; or
• Some other thread interrupts the current thread.

If the current thread:

• has its interrupted status set on entry to this method; or
• is interrupted while waiting,

then InterruptedException is thrown and the current thread's interrupted status is cleared.

Throws:

InterruptedException - if the current thread is interrupted while waiting

await

public boolean await(long timeout,
 TimeUnit unit)
              throws InterruptedException

Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted, or the specified waiting time elapses.

If the current count is zero then this method returns immediately with the value true.

If the current count is greater than zero then the current thread becomes disabled for thread scheduling purposes and lies dormant until one of three things happen:

• The count reaches zero due to invocations of the countDown() method; or
• Some other thread interrupts the current thread; or
• The specified waiting time elapses.

If the count reaches zero then the method returns with the value true.

If the current thread:

• has its interrupted status set on entry to this method; or
• is interrupted while waiting,

then InterruptedException is thrown and the current thread's interrupted status is cleared.

If the specified waiting time elapses then the value false is returned. If the time is less than or equal to zero, the method will not wait at all.

Parameters:

timeout - the maximum time to wait

unit - the time unit of the timeout argument

Returns:

true if the count reached zero and false if the waiting time elapsed before the count reached zero

Throws:

InterruptedException - if the current thread is interrupted while waiting

countDown

public void countDown()

Decrements the count of the latch, releasing all waiting threads if the count reaches zero.

If the current count is greater than zero then it is decremented. If the new count is zero then all waiting threads are re-enabled for thread scheduling purposes.

If the current count equals zero then nothing happens.

countDown

public void countDown(int count)

Decrements the count of the latch, releasing all waiting threads if the count reaches zero.

If the current count is greater than zero then it is decremented. If the new count is zero then all waiting threads are re-enabled for thread scheduling purposes.

If the current count equals zero then nothing happens.

Parameters:

count - the number of counts to decrease

countUp

public void countUp()

Increments the count of the latch by one.

countUp

public void countUp(int count)

Increments the count of the latch by a positive number.

Parameters:

count - the number of counts to increase

getCount

public long getCount()

Returns the current count.

This method is typically used for debugging and testing purposes.

Returns:

the current count

toString

public String toString()

Returns a string identifying this latch, as well as its state. The state, in brackets, includes the String "Count =" followed by the current count.

Overrides:

toString in class Object

Returns:

a string identifying this latch, as well as its state