java.lang.Object | |
↳ | java.util.concurrent.Executors |
Factory and utility methods for Executor
, ExecutorService
, ScheduledExecutorService
, ThreadFactory
, and Callable
classes defined in this
package. This class supports the following kinds of methods:
ExecutorService
set up with commonly useful configuration settings.
ScheduledExecutorService
set up with commonly useful configuration settings.
ThreadFactory
that sets newly created threads to a known state.
Callable
out of other closure-like forms, so they can be used
in execution methods requiring Callable.
Public Methods | |||||||||||
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Returns a
Callable object that, when
called, runs the given task and returns null. | |||||||||||
Returns a
Callable object that, when
called, runs the given privileged exception action and returns
its result. | |||||||||||
Returns a
Callable object that, when
called, runs the given privileged action and returns its result. | |||||||||||
Returns a
Callable object that, when
called, runs the given task and returns the given result. | |||||||||||
Returns a default thread factory used to create new threads.
| |||||||||||
Creates a thread pool that creates new threads as needed, but
will reuse previously constructed threads when they are
available.
| |||||||||||
Creates a thread pool that creates new threads as needed, but
will reuse previously constructed threads when they are
available, and uses the provided
ThreadFactory to create new threads when needed.
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Creates a thread pool that reuses a fixed number of threads
operating off a shared unbounded queue.
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Creates a thread pool that reuses a fixed number of threads
operating off a shared unbounded queue, using the provided
ThreadFactory to create new threads when needed.
| |||||||||||
Creates a thread pool that can schedule commands to run after a
given delay, or to execute periodically.
| |||||||||||
Creates a thread pool that can schedule commands to run after a
given delay, or to execute periodically.
| |||||||||||
Creates an Executor that uses a single worker thread operating
off an unbounded queue, and uses the provided ThreadFactory to
create a new thread when needed.
| |||||||||||
Creates an Executor that uses a single worker thread operating
off an unbounded queue.
| |||||||||||
Creates a single-threaded executor that can schedule commands
to run after a given delay, or to execute periodically.
| |||||||||||
Creates a single-threaded executor that can schedule commands
to run after a given delay, or to execute periodically.
| |||||||||||
Returns a
Callable object that will, when
called, execute the given callable under the current
access control context. | |||||||||||
Returns a
Callable object that will, when
called, execute the given callable under the current
access control context, with the current context class loader
as the context class loader. | |||||||||||
Returns a thread factory used to create new threads that
have the same permissions as the current thread.
| |||||||||||
Returns an object that delegates all defined
ExecutorService methods to the given executor, but not any
other methods that might otherwise be accessible using
casts. | |||||||||||
Returns an object that delegates all defined
ScheduledExecutorService methods to the given executor, but
not any other methods that might otherwise be accessible using
casts. |
[Expand]
Inherited Methods | |||||||||||
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From class java.lang.Object
|
Returns a Callable
object that, when
called, runs the given task and returns null.
task | the task to run |
---|
NullPointerException | if task null |
---|
Returns a Callable
object that, when
called, runs the given privileged exception action and returns
its result.
action | the privileged exception action to run |
---|
NullPointerException | if action null |
---|
Returns a Callable
object that, when
called, runs the given privileged action and returns its result.
action | the privileged action to run |
---|
NullPointerException | if action null |
---|
Returns a Callable
object that, when
called, runs the given task and returns the given result. This
can be useful when applying methods requiring a
Callable to an otherwise resultless action.
task | the task to run |
---|---|
result | the result to return |
NullPointerException | if task null |
---|
Returns a default thread factory used to create new threads.
This factory creates all new threads used by an Executor in the
same ThreadGroup
. If there is a SecurityManager
, it uses the group of getSecurityManager()
, else the group of the thread
invoking this defaultThreadFactory method. Each new
thread is created as a non-daemon thread with priority set to
the smaller of Thread.NORM_PRIORITY and the maximum
priority permitted in the thread group. New threads have names
accessible via getName()
of
pool-N-thread-M, where N is the sequence
number of this factory, and M is the sequence number
of the thread created by this factory.
Creates a thread pool that creates new threads as needed, but
will reuse previously constructed threads when they are
available. These pools will typically improve the performance
of programs that execute many short-lived asynchronous tasks.
Calls to execute will reuse previously constructed
threads if available. If no existing thread is available, a new
thread will be created and added to the pool. Threads that have
not been used for sixty seconds are terminated and removed from
the cache. Thus, a pool that remains idle for long enough will
not consume any resources. Note that pools with similar
properties but different details (for example, timeout parameters)
may be created using ThreadPoolExecutor
constructors.
Creates a thread pool that creates new threads as needed, but will reuse previously constructed threads when they are available, and uses the provided ThreadFactory to create new threads when needed.
threadFactory | the factory to use when creating new threads |
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NullPointerException | if threadFactory is null |
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Creates a thread pool that reuses a fixed number of threads
operating off a shared unbounded queue. At any point, at most
nThreads threads will be active processing tasks.
If additional tasks are submitted when all threads are active,
they will wait in the queue until a thread is available.
If any thread terminates due to a failure during execution
prior to shutdown, a new one will take its place if needed to
execute subsequent tasks. The threads in the pool will exist
until it is explicitly shutdown
.
nThreads | the number of threads in the pool |
---|
IllegalArgumentException | if nThreads <= 0 |
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Creates a thread pool that reuses a fixed number of threads
operating off a shared unbounded queue, using the provided
ThreadFactory to create new threads when needed. At any point,
at most nThreads threads will be active processing
tasks. If additional tasks are submitted when all threads are
active, they will wait in the queue until a thread is
available. If any thread terminates due to a failure during
execution prior to shutdown, a new one will take its place if
needed to execute subsequent tasks. The threads in the pool will
exist until it is explicitly shutdown
.
nThreads | the number of threads in the pool |
---|---|
threadFactory | the factory to use when creating new threads |
NullPointerException | if threadFactory is null |
---|---|
IllegalArgumentException | if nThreads <= 0 |
Creates a thread pool that can schedule commands to run after a given delay, or to execute periodically.
corePoolSize | the number of threads to keep in the pool, even if they are idle. |
---|
IllegalArgumentException | if corePoolSize < 0 |
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Creates a thread pool that can schedule commands to run after a given delay, or to execute periodically.
corePoolSize | the number of threads to keep in the pool, even if they are idle. |
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threadFactory | the factory to use when the executor creates a new thread. |
IllegalArgumentException | if corePoolSize < 0 |
---|---|
NullPointerException | if threadFactory is null |
Creates an Executor that uses a single worker thread operating off an unbounded queue, and uses the provided ThreadFactory to create a new thread when needed. Unlike the otherwise equivalent newFixedThreadPool(1, threadFactory) the returned executor is guaranteed not to be reconfigurable to use additional threads.
threadFactory | the factory to use when creating new threads |
---|
NullPointerException | if threadFactory is null |
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Creates an Executor that uses a single worker thread operating off an unbounded queue. (Note however that if this single thread terminates due to a failure during execution prior to shutdown, a new one will take its place if needed to execute subsequent tasks.) Tasks are guaranteed to execute sequentially, and no more than one task will be active at any given time. Unlike the otherwise equivalent newFixedThreadPool(1) the returned executor is guaranteed not to be reconfigurable to use additional threads.
Creates a single-threaded executor that can schedule commands to run after a given delay, or to execute periodically. (Note however that if this single thread terminates due to a failure during execution prior to shutdown, a new one will take its place if needed to execute subsequent tasks.) Tasks are guaranteed to execute sequentially, and no more than one task will be active at any given time. Unlike the otherwise equivalent newScheduledThreadPool(1) the returned executor is guaranteed not to be reconfigurable to use additional threads.
Creates a single-threaded executor that can schedule commands to run after a given delay, or to execute periodically. (Note however that if this single thread terminates due to a failure during execution prior to shutdown, a new one will take its place if needed to execute subsequent tasks.) Tasks are guaranteed to execute sequentially, and no more than one task will be active at any given time. Unlike the otherwise equivalent newScheduledThreadPool(1, threadFactory) the returned executor is guaranteed not to be reconfigurable to use additional threads.
threadFactory | the factory to use when creating new threads |
---|
NullPointerException | if threadFactory is null |
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Returns a Callable
object that will, when
called, execute the given callable under the current
access control context. This method should normally be
invoked within an doPrivileged(PrivilegedAction
action
to create callables that will, if possible, execute under the
selected permission settings holding within that action; or if
not possible, throw an associated AccessControlException
.
callable | the underlying task |
---|
NullPointerException | if callable null |
---|
Returns a Callable
object that will, when
called, execute the given callable under the current
access control context, with the current context class loader
as the context class loader. This method should normally be
invoked within an doPrivileged(PrivilegedAction
action
to create callables that will, if possible, execute under the
selected permission settings holding within that action; or if
not possible, throw an associated AccessControlException
.
callable | the underlying task |
---|
NullPointerException | if callable null |
---|---|
AccessControlException | if the current access control context does not have permission to both set and get context class loader. |
Returns a thread factory used to create new threads that
have the same permissions as the current thread.
This factory creates threads with the same settings as defaultThreadFactory()
, additionally setting the
AccessControlContext and contextClassLoader of new threads to
be the same as the thread invoking this
privilegedThreadFactory method. A new
privilegedThreadFactory can be created within an
doPrivileged(PrivilegedAction
action setting the
current thread's access control context to create threads with
the selected permission settings holding within that action.
Note that while tasks running within such threads will have
the same access control and class loader settings as the
current thread, they need not have the same ThreadLocal
or InheritableThreadLocal
values. If necessary,
particular values of thread locals can be set or reset before
any task runs in ThreadPoolExecutor
subclasses using
beforeExecute(Thread, Runnable)
. Also, if it is
necessary to initialize worker threads to have the same
InheritableThreadLocal settings as some other designated
thread, you can create a custom ThreadFactory in which that
thread waits for and services requests to create others that
will inherit its values.
AccessControlException | if the current access control context does not have permission to both get and set context class loader. |
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Returns an object that delegates all defined ExecutorService
methods to the given executor, but not any
other methods that might otherwise be accessible using
casts. This provides a way to safely "freeze" configuration and
disallow tuning of a given concrete implementation.
executor | the underlying implementation |
---|
NullPointerException | if executor null |
---|
Returns an object that delegates all defined ScheduledExecutorService
methods to the given executor, but
not any other methods that might otherwise be accessible using
casts. This provides a way to safely "freeze" configuration and
disallow tuning of a given concrete implementation.
executor | the underlying implementation |
---|
NullPointerException | if executor null |
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