ClassRidgetMapper.java

/*******************************************************************************
 * Copyright (c) 2007, 2014 compeople AG and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *    compeople AG - initial API and implementation
 *******************************************************************************/
package org.eclipse.riena.ui.ridgets;

import java.lang.reflect.Modifier;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

import org.osgi.service.log.LogService;

import org.eclipse.core.databinding.BindingException;
import org.eclipse.equinox.log.Logger;

import org.eclipse.riena.core.Log4r;
import org.eclipse.riena.core.singleton.SingletonProvider;
import org.eclipse.riena.internal.ui.ridgets.Activator;

/**
 * A mapper that maps ridget interfaces to concrete ridget implementations.
 * 
 * @since 2.0
 */
public final class ClassRidgetMapper {

	private static final SingletonProvider<ClassRidgetMapper> CRM = new SingletonProvider<ClassRidgetMapper>(
			ClassRidgetMapper.class);

	private final Map<Class<? extends IRidget>, Class<? extends IRidget>> mappings = Collections
			.synchronizedMap(new HashMap<Class<? extends IRidget>, Class<? extends IRidget>>());

	private static final Logger LOGGER = Log4r.getLogger(Activator.getDefault(), ClassRidgetMapper.class);

	/**
	 * Answer the singleton <code>ClassRidgetMapper</code>
	 * 
	 * @return the ClassRidgetMapper singleton
	 */
	public static ClassRidgetMapper getInstance() {
		return CRM.getInstance();
	}

	private ClassRidgetMapper() {
	}

	/**
	 * Adds an Interface Class pair to the mapper. If the Interface is already
	 * existent, the previous value will be overwritten.
	 * 
	 * @param ridgetInterface
	 *            an interface extending <code>IRidget</code>
	 * @param ridgetClazz
	 *            a concrete class implementing <code>IRidget</code>. If
	 *            ridgetClazz is abstract or an interface it will not be added
	 *            and warning is logged.
	 */
	public void addMapping(final Class<? extends IRidget> ridgetInterface, final Class<? extends IRidget> ridgetClazz) {
		if (ridgetInterface == null || ridgetClazz == null) {
			return;
		}

		if (!ridgetClazz.isInterface() && !Modifier.isAbstract(ridgetClazz.getModifiers())) {
			mappings.put(ridgetInterface, ridgetClazz);
		} else {
			LOGGER.log(LogService.LOG_WARNING, "The interface " + ridgetInterface.getName() + " and the class " //$NON-NLS-1$//$NON-NLS-2$
					+ ridgetClazz.getName() + " could not be added to the map, because " + ridgetClazz.getName() //$NON-NLS-1$
					+ " is an abstract class or an interface"); //$NON-NLS-1$
		}
	}

	/**
	 * Returns the ridget class that belongs to the ridgetInterface in the
	 * mapper.
	 * 
	 * @param ridgetInterface
	 *            the key to search for
	 * @return the ridget class that belongs to the ridgetInterface in the
	 *         mapper
	 * @throws throws a <code>BindingException</code> if the ridgetInterface
	 *         cannot be found in the mapper.
	 */
	public Class<? extends IRidget> getRidgetClass(final Class<? extends IRidget> ridgetInterface) {
		final Class<? extends IRidget> ridgetClass = mappings.get(ridgetInterface);
		if (ridgetClass != null) {
			return ridgetClass;
		}

		throw new BindingException("No Ridget class defined for interface " + ridgetInterface.getName()); //$NON-NLS-1$
	}
}