/*
* Copyright 2012 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.google.gwt.view.client;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
/**
* A simple selection model that allows multiple items to be selected and
* retains order of selection. Selecting the same item multiple times does not
* change the order (item won't be moved to the end of selection).
*
* OrderedMultiSelectionModel uses LinkedHashMaps, which may increase the size
* of your compiled output if you do not use LinkedHashMaps elsewhere in your
* application.
*
* @param <T> the record data type
*/
public class OrderedMultiSelectionModel<T> extends MultiSelectionModel<T> {
/**
* Constructs a OrderedMultiSelectionModel without a key provider.
*/
public OrderedMultiSelectionModel() {
this(null);
}
/**
* Constructs a OrderedMultiSelectionModel with the given key provider.
*
* @param keyProvider an instance of ProvidesKey<T>, or null if the item
* should act as its own key
*/
public OrderedMultiSelectionModel(ProvidesKey<T> keyProvider) {
super(keyProvider, new LinkedHashMap<Object, T>(),
new LinkedHashMap<Object, SelectionChange<T>>());
}
/**
* Get the List of selected items as a copy.
*
* @return the list of selected items in the order of additions. Selecting an
* element already in the selection does not move it to the end of the
* list.
*/
public List<T> getSelectedList() {
resolveChanges();
return new ArrayList<T>(selectedSet.values());
}
}