org.apache.commons.pool2
Interface PooledObject<T>

Type Parameters:

T - the type of object in the pool

All Superinterfaces:

Comparable<PooledObject<T>>

All Known Implementing Classes:

DefaultPooledObject, PooledSoftReference

public interface PooledObject<T>
extends Comparable<PooledObject<T>>

Defines the wrapper that is used to track the additional information, such as state, for the pooled objects.

Implementations of this class are required to be thread-safe.

Since:

2.0

Version:

$Revision: $

getObject

T getObject()

Obtain the underlying object that is wrapped by this instance of PooledObject.

Returns:

The wrapped object

getCreateTime

long getCreateTime()

Obtain the time (using the same basis as System.currentTimeMillis()) that this object was created.

Returns:

The creation time for the wrapped object

getActiveTimeMillis

long getActiveTimeMillis()

Obtain the time in milliseconds that this object last spent in the the active state (it may still be active in which case subsequent calls will return an increased value).

Returns:

The time in milliseconds last spent in the active state

getIdleTimeMillis

long getIdleTimeMillis()

Obtain the time in milliseconds that this object last spend in the the idle state (it may still be idle in which case subsequent calls will return an increased value).

Returns:

The time in milliseconds last spent in the idle state

getLastBorrowTime

long getLastBorrowTime()

Obtain the time the wrapped object was last borrowed.

Returns:

The time the object was last borrowed

getLastReturnTime

long getLastReturnTime()

Obtain the time the wrapped object was last returned.

Returns:

The time the object was last returned

getLastUsedTime

long getLastUsedTime()

Return an estimate of the last time this object was used. If the class of the pooled object implements TrackedUse, what is returned is the maximum of TrackedUse.getLastUsed() and getLastBorrowTime(); otherwise this method gives the same value as getLastBorrowTime().

Returns:

the last time this object was used

compareTo

int compareTo(PooledObject<T> other)

Orders instances based on idle time - i.e. the length of time since the instance was returned to the pool. Used by the GKOP idle object evictor.

Note: This class has a natural ordering that is inconsistent with equals if distinct objects have the same identity hash code.

Specified by:

compareTo in interface Comparable<PooledObject<T>>

equals

boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

int hashCode()

Overrides:

hashCode in class Object

toString

String toString()

Provides a String form of the wrapper for debug purposes. The format is not fixed and may change at any time.

Overrides:

toString in class Object

startEvictionTest

boolean startEvictionTest()

Attempt to place the pooled object in the PooledObjectState.EVICTION state.

Returns:

true if the object was placed in the PooledObjectState.EVICTION state otherwise false

endEvictionTest

boolean endEvictionTest(Deque<PooledObject<T>> idleQueue)

Called to inform the object that the eviction test has ended.

Parameters:

idleQueue - The queue if idle objects to which the object should be returned

Returns:

Currently not used

allocate

boolean allocate()

Allocates the object.

Returns:

true if the original state was IDLE

deallocate

boolean deallocate()

Deallocates the object and sets it IDLE if it is currently ALLOCATED.

Returns:

true if the state was ALLOCATED

invalidate

void invalidate()

Sets the state to INVALID

setLogAbandoned

void setLogAbandoned(boolean logAbandoned)

Is abandoned object tracking being used? If this is true the implementation will need to record the stack trace of the last caller to borrow this object.

Parameters:

logAbandoned - The new configuration setting for abandoned object tracking

use

void use()

Record the current stack trace as the last time the object was used.

printStackTrace

void printStackTrace(PrintWriter writer)

Prints the stack trace of the code that borrowed this pooled object and the stack trace of the last code to use this object (if available) to the supplied writer.

Parameters:

writer - The destination for the debug output

getState

PooledObjectState getState()

Returns the state of this object.

Returns:

state

markAbandoned

void markAbandoned()

Marks the pooled object as abandoned.

markReturning

void markReturning()

Marks the object as returning to the pool.