org.gatein.wsrp

Class SupportsLastModified

java.lang.Object

org.gatein.wsrp.SupportsLastModified

public class SupportsLastModified
extends Object

Encapsulates support for last modification checking, the returned values being not useful by themselves but rather as a means to compare them to another such value. Useful for quick dirty checking of objects.

Author:

Chris Laprun

Constructor Summary

Constructors

Constructor and Description
SupportsLastModified()

Method Summary

Methods

Modifier and Type	Method and Description
long	getLastModified() Retrieves a long value recording when (with unspecified origin) this object was last modified.
void	modifyNow() Specifies that this object is modified as of now, as specified by now().
protected boolean	modifyNowIfNeeded(Object oldValue, Object newValue) Sets the last modified time to now (as returned by now()) if the specified values, presumably fields of the calling object, are different.
static long	now() Retrieves a value representing the current instant / now, without specified origin so shouldn't be depended on to mark a meaningful instant in time by itself.
void	setLastModified(long lastModified) Sets the last modified marker to the specified value.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SupportsLastModified

public SupportsLastModified()

Method Detail

modifyNowIfNeeded

protected boolean modifyNowIfNeeded(Object oldValue,
                        Object newValue)

Sets the last modified time to now (as returned by now()) if the specified values, presumably fields of the calling object, are different. This method is useful to marks this object as modified when setting a field to the specified new value would result in a modification of the object based on the specified current/old value of the field. Values are compared using ParameterValidation.isOldAndNewDifferent(Object, Object).

Parameters:

oldValue - the current / old value that might be replaced by the specified new value

newValue - the new value that might replace the current / old one

Returns:

true if both given values were different and therefore would lead to the calling object being set as modified now, false otherwise.

modifyNow

public void modifyNow()

Specifies that this object is modified as of now, as specified by now().

getLastModified

public long getLastModified()

Retrieves a long value recording when (with unspecified origin) this object was last modified. Since the time origin is unspecified, the returned value shouldn't be understood as useful in itself. It only takes meaning when comparing it to another such value to compute an interval. Therefore, only differences between returned values matter, not individual values which do not necessarily mark a useful (in itself) point in time.

Returns:

a long value recording when (with unspecified origin) this object was last modified.

setLastModified

public void setLastModified(long lastModified)

Sets the last modified marker to the specified value. Note that this method probably shouldn't be used directly by client code which should use modifyNow() instead. This method is available for persistence layer implementations to restore value from storage.

Parameters:

lastModified - the new last modified time marker

now

public static long now()

Retrieves a value representing the current instant / now, without specified origin so shouldn't be depended on to mark a meaningful instant in time by itself. The value is however guaranteed to be meaningful with respect to comparison with previous or future invocations of this method.

Returns:

a value representing the current instant / now, without specified origin.