xapi.inject.impl

Class LazyMerger<K1,K2,V>

java.lang.Object

xapi.inject.impl.LazyMerger<K1,K2,V>

Type Parameters:

K1 -

K2 -

V -

All Implemented Interfaces:

MergesValues<K1,K2,V>

public class LazyMerger<K1,K2,V>
extends Object
implements MergesValues<K1,K2,V>

A default object designed to convert two values into one value.
The #create(K1, K2) method is provided to initializes the value. If you use a constructor that accepts another MergesValues, that delegate will only be called to create the value object. If you override the create method, it will be called until it returns non null.
If you want to perform some initialization on every call to #merge(K1, K2), you should override the #refresh(K1, K2, V) method.
Care should be taken to only perform idempotent actions inside the refresh method, as implementations are free to assume it is safe (and performant) to call refresh many times.

Author:

"James X. Nelson (james@wetheinter.net)"

Constructor Summary

Constructors

Constructor and Description
LazyMerger()
LazyMerger(MergesValues<K1,K2,V> merger)
LazyMerger(MergesValues<K1,K2,V> merger, V value)
LazyMerger(V value)

Method Summary

Modifier and Type	Method and Description
protected V	create(K1 k1, K2 k2)
V	merge(K1 k1, K2 k2)
protected void	refresh(K1 k1, K2 k2, V value) Default action is to do nothing.

Methods inherited from class java.lang.Object

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

Constructor Detail

LazyMerger

public LazyMerger()

LazyMerger

public LazyMerger(MergesValues<K1,K2,V> merger)

LazyMerger

public LazyMerger(MergesValues<K1,K2,V> merger,
                  V value)

LazyMerger

public LazyMerger(V value)

Method Detail

merge

public final V merge(K1 k1,
                     K2 k2)

Specified by:

merge in interface MergesValues<K1,K2,V>

refresh

protected void refresh(K1 k1,
                       K2 k2,
                       V value)

Default action is to do nothing.
This method is provided so you can fill in actions that should be taken on the value result, (only called when the value is not null).

create

protected V create(K1 k1,
                   K2 k2)