AcceleratorRepository.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.framework.resources;

import javax.swing.KeyStroke;

/**
 * This interface provides a convenient protocol for clients
 * to fetch the accelerator for a given key. The key is typically the
 * same key used to fetch the accelerator's action label from a
 * StringRepository, with ".ACCELERATOR" appended to it.
 *
 * @see StringRepository
 */
public interface AcceleratorRepository {

    boolean hasAccelerator(String key);

    KeyStroke getAccelerator(String key);


    // ********** null implementation **********

    /**
     * This instance will throw an exception for any non-null key
     * and return null for any null key.
     */
    AcceleratorRepository NULL_INSTANCE =
        new AcceleratorRepository() {
            public boolean hasAccelerator(String key) {
                return key == null;
            }
            public KeyStroke getAccelerator(String key) {
                if (key == null) {
                    return null;
                }
                throw new MissingAcceleratorException("Missing accelerator: " + key, key);
            }
            public String toString() {
                return "NullAcceleratorRepository";
            }
        };

}