Package org.apache.wicket.markup.repeater

Class ReuseIfModelsEqualStrategy

java.lang.Object

org.apache.wicket.markup.repeater.ReuseIfModelsEqualStrategy

All Implemented Interfaces:

Serializable, IItemReuseStrategy, org.apache.wicket.util.io.IClusterable

public class ReuseIfModelsEqualStrategy
extends Object
implements IItemReuseStrategy

Reuse strategy that will reuse an old item if its model is equal to a model inside the newModels iterator. Useful when state needs to be kept across requests for as long as the item is visible within the view.

Notice that the model and not the model object needs to implement the Object.equals(Object) and Object.hashCode() methods. Most of the time it is a good idea to forward the calls to the object, however if a detachable model is used it is often enough to compare an identifier for the object the models are pointing to ( this saves the model from loading the object).

Author:

Igor Vaynberg (ivaynberg)

See Also:

• Serialized Form

Constructor Summary

Constructors

Constructor	Description
ReuseIfModelsEqualStrategy()

Method Summary

Modifier and Type	Method	Description
static IItemReuseStrategy	getInstance()
<T> Iterator<Item<T>>	getItems(IItemFactory<T> factory, Iterator<IModel<T>> newModels, Iterator<Item<T>> existingItems)	Returns an iterator over items that will be added to the view.

Methods inherited from class java.lang.Object

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

Constructor Details

ReuseIfModelsEqualStrategy

public ReuseIfModelsEqualStrategy()

Method Details

getInstance

public static IItemReuseStrategy getInstance()

Returns:

static instance

getItems

public <T> Iterator<Item<T>> getItems(IItemFactory<T> factory,
 Iterator<IModel<T>> newModels,
 Iterator<Item<T>> existingItems)

Description copied from interface: IItemReuseStrategy

Returns an iterator over items that will be added to the view. The iterator needs to return all the items because the old ones are removed prior to the new ones added.

Specified by:

getItems in interface IItemReuseStrategy

Type Parameters:

T - type of Item

Parameters:

factory - implementation of IItemFactory

newModels - iterator over models for items

existingItems - iterator over child items

Returns:

iterator over items that will be added after all the old items are moved.

See Also:

• IItemReuseStrategy.getItems(org.apache.wicket.markup.repeater.IItemFactory, java.util.Iterator, java.util.Iterator)