Module org.eclipse.jetty.util

Package org.eclipse.jetty.util

Interface Pool<P>

Type Parameters:

P - the type of the pooled objects

All Known Implementing Classes:

ConcurrentPool, LockedPool, Pool.Wrapper

@ManagedObject
public interface Pool<P>

A pool of objects, with support for multiplexing and several optimized strategies plus an optional ThreadLocal cache of the last released entry.

A Pool should be terminated when it is no longer needed; once terminated, it cannot be used anymore.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static interface	Pool.Entry<E>	A Pool entry that holds metadata and a pooled object.
static interface	Pool.Factory<F>	A factory for Pool instances.
static class	Pool.Wrapper<W>	A wrapper for Pool instances.

Method Summary

Modifier and Type	Method	Description
Pool.Entry<P>	acquire()	Acquires an entry from the pool.
default Pool.Entry<P>	acquire(Function<Pool.Entry<P>,P> creator)	Acquires an entry from the pool, reserving and creating a new entry if necessary.
default int	getIdleCount()
default int	getInUseCount()
int	getMaxSize()
default int	getReservedCount()
default int	getTerminatedCount()
boolean	isTerminated()
Pool.Entry<P>	reserve()	Creates a new disabled slot into the pool.
int	size()
Stream<Pool.Entry<P>>	stream()
Collection<Pool.Entry<P>>	terminate()	Terminates this Pool.

Method Details

reserve

Pool.Entry<P> reserve()

Creates a new disabled slot into the pool.

The returned entry must ultimately have the Pool.Entry.enable(Object, boolean) method called or be removed via Pool.Entry.remove().

Returns:

a disabled entry that is contained in the pool, or null if the pool is terminated or if the pool cannot reserve an entry

acquire

Pool.Entry<P> acquire()

Acquires an entry from the pool.

Only enabled entries will be returned from this method and their Pool.Entry.enable(Object, boolean) method must not be called.

Returns:

an entry from the pool or null if none is available.

acquire

default Pool.Entry<P> acquire(Function<Pool.Entry<P>,P> creator)

Acquires an entry from the pool, reserving and creating a new entry if necessary.

Parameters:

creator - a function to create the pooled value for a reserved entry.

Returns:

an entry from the pool or null if none is available.

isTerminated

boolean isTerminated()

Returns:

whether this Pool has been terminated

See Also:

• terminate()

terminate

Collection<Pool.Entry<P>> terminate()

Terminates this Pool.

All the entries are marked as terminated and cannot be acquired nor released, but only removed.

The returned list of all entries may be iterated to perform additional operations on the pooled objects.

The pool cannot be used anymore after it is terminated.

Returns:

a list of all entries

size

@ManagedAttribute("The number of entries")
int size()

Returns:

the current number of entries in this Pool

getMaxSize

@ManagedAttribute("The maximum number of entries")
int getMaxSize()

Returns:

the maximum number of entries in this Pool

stream

Stream<Pool.Entry<P>> stream()

Returns:

a Stream over the entries

getReservedCount

@ManagedAttribute("The number of reserved entries")
default int getReservedCount()

Returns:

the number of reserved entries

getIdleCount

@ManagedAttribute("The number of idle entries")
default int getIdleCount()

Returns:

the number of idle entries

getInUseCount

@ManagedAttribute("The number of in-use entries")
default int getInUseCount()

Returns:

the number of in-use entries

getTerminatedCount

@ManagedAttribute("The number of terminated entries")
default int getTerminatedCount()

Returns:

the number of terminated entries