PersistenceCallbackRegistry.java

/*
 * Copyright 2014 the original author or authors.
 *
 * 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 org.springframework.sync.diffsync;

import java.util.HashMap;
import java.util.Map;

import org.springframework.sync.Patch;

/**
 * Registry for looking up {@link PersistenceCallback}s to be used in the course of applying a {@link Patch} via
 * Differential Synchronization.
 * 
 * @author Craig Walls
 */
public class PersistenceCallbackRegistry {

	private Map<String, PersistenceCallback<?>> persistenceCallbacks = new HashMap<String, PersistenceCallback<?>>();
	
	public PersistenceCallbackRegistry() {}
	
	/**
	 * Adds a {@link PersistenceCallback} to the registry with a key that is pluralized by the pluralize() method.
	 * @param persistenceCallback the {@link PersistenceCallback} to add to the registry.
	 */
	public void addPersistenceCallback(PersistenceCallback<?> persistenceCallback) {
		Class<?> entityType = persistenceCallback.getEntityType();
		String key = pluralize(entityType.getSimpleName());
		persistenceCallbacks.put(key, persistenceCallback);
	}
	
	/**
	 * Looks up a {@link PersistenceCallback} from the registry.
	 * @param key the key that the {@link PersistenceCallback} has been registered under.
	 * @return the {@link PersistenceCallback}
	 */
	public PersistenceCallback<?> findPersistenceCallback(String key) {
		return persistenceCallbacks.get(key);
	}
	
	/**
	 * Pluralizes an entity's type name. Default implementation is to naively add an 's' to the end of the given String.
	 * Override to implement a more elegant pluralization technique.
	 * @param entityTypeName the entity type name to be pluralized.
	 * @return the pluralized type name.
	 */
	protected String pluralize(String entityTypeName) {
		return entityTypeName.toLowerCase() + "s";
	}
	
}