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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.component;

/**
 * Abstract implementation of a composite component that keeps track of its child components at specific indices in an array. The array is indexed using the
 * provided enum. Child components should not directly call {@link #addComponent(Component)} and {@link #removeComponent(Component)}. Each index in the array
 * can be null. Iterating over child components is thread safe.
 * 
 * This class should be constructed using Enum.values() to indicate the possible enum values.
 * 
 * @param  The enum to index child components.
 * @author Garret Wilson
 */
public abstract class AbstractEnumCompositeComponent> extends AbstractArrayCompositeComponent {

	/**
	 * Returns the component for the given enum value.
	 * @param e The enum value indicating the component to return.
	 * @return The component associated with the given enum value.
	 */
	protected Component getComponent(final E e) {
		return super.getComponent(e.ordinal()); //look up the component in the array
	}

	/**
	 * Sets the component for the given enum value. If the new component is the same as the old, no action is taken. This implementation calls
	 * {@link #addComponent(Component)} and {@link #removeComponent(Component)} as necessary.
	 * @param e The enum value indicating the component to set.
	 * @param newComponent The component to associate with the enum value.
	 * @return The component previously associated for the enum value.
	 * @see #addComponent(Component)
	 * @see #removeComponent(Component)
	 */
	protected Component setComponent(final E e, final Component newComponent) {
		return super.setComponent(e.ordinal(), newComponent); //look up the component in the array
	}

	/**
	 * Enum values constructor.
	 * @param enumValues The values of enums that allow access to the underlying array.
	 * @throws NullPointerException if the given enum values array is null.
	 */
	public AbstractEnumCompositeComponent(final E[] enumValues) {
		super(enumValues.length); //construct the parent class
	}

}