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Guise™ Internet application framework.

There is a newer version: 0.5.3

/*
 * Copyright © 2005-2008 GlobalMentor, 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 io.guise.framework.model;

/**
 * An implementation of a selection strategy for a select model allowing only a single selection at a time. This class is marked final because it demarcates
 * certain selection semantics that, if they can be assumed, may be offloaded to a component's view in certain circumstances. This class is thread-safe, and
 * assumes that the corresponding select model is thread-safe, synchronized on itself.
 * @param  The type of values contained in the select model.
 * @author Garret Wilson
 * @see ListSelectModel
 */
public final class SingleListSelectionPolicy extends AbstractListSelectionPolicy {

	/**
	 * {@inheritDoc}
	 * 
	 * This implementation only allows the first index to be set.
	 * 
	 */
	@Override
	public int[] getSetSelectedIndices(final ListSelectModel selectModel, final int[] indices) {
		return indices.length <= 1 ? indices : new int[] { indices[0] }; //if there is more than one index requested, only use the first
	}

	/**
	 * {@inheritDoc}
	 * 
	 * This implementation allows the addition of all requested indices.
	 * 
	 */
	@Override
	public int[] getAddSelectedIndices(final ListSelectModel selectModel, final int[] indices) {
		if(selectModel.isEmpty()) { //if the model is empty
			return indices.length <= 1 ? indices : new int[] { indices[0] }; //allow at most one index to be set			
		} else { //if the model isn't empty
			return new int[] {}; //don't allow anything to be added
		}
	}

}