com.rshtech.util
Class CachedObject<T>

java.lang.Object
  com.rshtech.util.CachedObject<T>

All Implemented Interfaces:

Cached

Direct Known Subclasses:

SoftCachedObject

public class CachedObject<T>
extends java.lang.Object
implements Cached

A simple Cached implementation which allows you to track the lifecycle of an object (when it was created, whether it has expired, etc). This enclosure allows you to handle single object caching; that is, if you do not need a collection of keyed objects (see ObjectCache) but just one object.

Version:

$Revision: 3129 $

Author:

$Author: kostya $

Field Summary

protected long	creationTime
static int	DISABLED
protected long	expirationLimit
protected long	lastUseTime
protected boolean	manuallyExpired
protected long	unusedExpirationLimit

Constructor Summary

protected	CachedObject()
	CachedObject(T valueObj)
	CachedObject(T valueObj, long expirationVal, long unusedExpirationVal)
protected	CachedObject(T valueObj, long expirationVal, long unusedExpirationVal, boolean ignoreNull)

Method Summary

boolean	equals(java.lang.Object rhs)
void	expire() Forcibly expire the object regardless of its internal state.
long	getCreationTime() Returns the time (in milliseconds) the object was created.
long	getExpirationLimit() Get the expiration limit (in milliseconds).
long	getLastUseTime() Returns the last time (in milliseconds) this object was used or accessed.
long	getUnusedExpirationLimit() Get the expiration limit (in milliseconds).
T	getValue()
int	hashCode()
boolean	isExpired() Is the implementation expired (should it be removed from a cache or discarded)?
boolean	isExpired(long expirationVal, long unusedExpirationVal) Is the implementation expired (should it be removed from a cache or discarded) based on the supplied criteria?
void	renew() Renew an object (at least removing a forcible expiration, possibly resetting internal state).
protected void	setCreationTime()
void	setExpirationLimit(long expirationVal) Set the expiration limit (in milliseconds).
void	setLastUseTime() Notify the implementation that it should mark the last use time using the current time.
void	setLastUseTime(long lastUseTime) Set the last use time for the implementation using the specified value (in milliseconds).
void	setUnusedExpirationLimit(long expirationVal) Set the unused expiration limit (in milliseconds).
void	setValue(T value)
java.lang.String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

DISABLED

public static final int DISABLED

See Also:

Constant Field Values

creationTime

protected long creationTime

lastUseTime

protected long lastUseTime

expirationLimit

protected long expirationLimit

unusedExpirationLimit

protected long unusedExpirationLimit

manuallyExpired

protected boolean manuallyExpired

Constructor Detail

CachedObject

public CachedObject(T valueObj)

Parameters:

valueObj - the object to cache

CachedObject

public CachedObject(T valueObj,
                    long expirationVal,
                    long unusedExpirationVal)

Parameters:

valueObj - the object to cache

CachedObject

protected CachedObject()

Parameters:

valueObj - the object to cache

CachedObject

protected CachedObject(T valueObj,
                       long expirationVal,
                       long unusedExpirationVal,
                       boolean ignoreNull)

Parameters:

valueObj - the object to cache

Method Detail

getValue

public T getValue()

Returns:

Returns the value.

setValue

public void setValue(T value)

Parameters:

value - The value to set.

getCreationTime

public long getCreationTime()

Description copied from interface: Cached

Returns the time (in milliseconds) the object was created. The created time usually reflects when the object was cached, not when it was necessarily created (although the two can be the same).

Specified by:

getCreationTime in interface Cached

Returns:

the creation time in milliseconds

getLastUseTime

public long getLastUseTime()

Description copied from interface: Cached

Returns the last time (in milliseconds) this object was used or accessed. It is the job of the implementation to set this value or the enclosing code or data structure must do it using setLastUseTime().

Specified by:

getLastUseTime in interface Cached

Returns:

the last time (in milliseconds) this object was used.

setLastUseTime

public void setLastUseTime()

Description copied from interface: Cached

Notify the implementation that it should mark the last use time using the current time.

Specified by:

setLastUseTime in interface Cached

setLastUseTime

public void setLastUseTime(long lastUseTime)

Description copied from interface: Cached

Set the last use time for the implementation using the specified value (in milliseconds).

Specified by:

setLastUseTime in interface Cached

Parameters:

lastUseTime - the milliseconds value to use.

isExpired

public boolean isExpired()

Description copied from interface: Cached

Is the implementation expired (should it be removed from a cache or discarded)?

Specified by:

isExpired in interface Cached

Returns:

true of the internal state of the implementation shows it to be expired or stale, false otherwise.

isExpired

public boolean isExpired(long expirationVal,
                         long unusedExpirationVal)

Description copied from interface: Cached

Is the implementation expired (should it be removed from a cache or discarded) based on the supplied criteria?

Specified by:

isExpired in interface Cached

Parameters:

expirationVal - the amount of milliseconds that can pass since the creation time before the implementation is considered expired. A value of -1 is considered a "disabled" value and such values should then be ignored (that is the implementation should never expire on the creation time).

unusedExpirationVal - the amount of milliseconds that can pass since the last use time before the implementation is considered expired. A value of -1 is considered a "disabled" value and such values should then be ignored (that is the implementation should never expire on the last use time).

Returns:

true of the internal state of the implementation shows it to be expired or stale, false otherwise.

expire

public void expire()

Description copied from interface: Cached

Forcibly expire the object regardless of its internal state.

Specified by:

expire in interface Cached

renew

public void renew()

Description copied from interface: Cached

Renew an object (at least removing a forcible expiration, possibly resetting internal state).

Specified by:

renew in interface Cached

getExpirationLimit

public long getExpirationLimit()

Description copied from interface: Cached

Get the expiration limit (in milliseconds). The expiration limit is the amount of milliseconds that can pass since the creation time before the implementation is considered expired. A value of -1 is considered a "disabled" value and such values should then be ignored (that is the implementation should never expire on the creation time).

Specified by:

getExpirationLimit in interface Cached

setExpirationLimit

public void setExpirationLimit(long expirationVal)

Description copied from interface: Cached

Set the expiration limit (in milliseconds).

Specified by:

setExpirationLimit in interface Cached

Parameters:

expirationVal - the amount of milliseconds that can pass since the creation time before the implementation is considered expired. A value of -1 is considered a "disabled" value and such values should then be ignored (that is the implementation should never expire on the creation time).

getUnusedExpirationLimit

public long getUnusedExpirationLimit()

Description copied from interface: Cached

Get the expiration limit (in milliseconds). The expiration limit is the amount of milliseconds that can pass since the last use time before the implementation is considered expired. A value of -1 is considered a "disabled" value and such values should then be ignored (that is the implementation should never expire on the last use time).

Specified by:

getUnusedExpirationLimit in interface Cached

setUnusedExpirationLimit

public void setUnusedExpirationLimit(long expirationVal)

Description copied from interface: Cached

Set the unused expiration limit (in milliseconds).

Specified by:

setUnusedExpirationLimit in interface Cached

Parameters:

expirationVal - the amount of milliseconds that can pass since the last use time before the implementation is considered expired. A value of -1 is considered a "disabled" value and such values should then be ignored (that is the implementation should never expire on the last use time).

equals

public boolean equals(java.lang.Object rhs)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

setCreationTime

protected void setCreationTime()