Class VariableLatch
CountDownLatch
except that it can also increase the count dynamically.-
Nested Class Summary
Modifier and TypeClassDescriptionprivate static final class
Synchronization control For CountDownLatch. -
Field Summary
-
Constructor Summary
ConstructorDescriptionVariableLatch
(int count) Constructs aCountDownLatch
initialized with the given count. -
Method Summary
Modifier and TypeMethodDescriptionvoid
await()
Causes the current thread to wait until the latch has counted down to zero, unless the thread is interrupted.boolean
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
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.toString()
Returns a string identifying this latch, as well as its state.
-
Field Details
-
sync
-
-
Constructor Details
-
VariableLatch
public VariableLatch(int count) Constructs aCountDownLatch
initialized with the given count.- Parameters:
count
- the number of timescountDown()
must be invoked before threads can pass throughawait()
- Throws:
IllegalArgumentException
- ifcount
is negative
-
-
Method Details
-
create
Create a new variable latch.- Returns:
- the variable latch; never null
-
create
Create a new variable latch.- Parameters:
initialValue
- the initial number of latches- Returns:
- the variable latch; never null
-
await
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,
InterruptedException
is thrown and the current thread's interrupted status is cleared.- Throws:
InterruptedException
- if the current thread is interrupted while waiting
- The count reaches zero due to invocations of the
-
await
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,
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 waitunit
- the time unit of thetimeout
argument- Returns:
true
if the count reached zero andfalse
if the waiting time elapsed before the count reached zero- Throws:
InterruptedException
- if the current thread is interrupted while waiting
- The count reaches zero due to invocations of the
-
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
Returns a string identifying this latch, as well as its state. The state, in brackets, includes the String"Count ="
followed by the current count.
-