/*
 * Copyright 2015 Robert von Burg <eitch@eitchnet.ch>
 * 
 * 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 li.strolch.policy;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import li.strolch.agent.api.ComponentContainer;
import li.strolch.agent.api.StrolchComponent;
import li.strolch.persistence.api.StrolchTransaction;
import li.strolch.service.api.Command;

/**
 * Interface for all Strolch policies, which are instantiated by the {@link PolicyHandler}
 * 
 * @author Robert von Burg <eitch@eitchnet.ch>
 */
public abstract class StrolchPolicy {

	protected static final Logger logger = LoggerFactory.getLogger(StrolchPolicy.class);

	private final ComponentContainer container;
	private final StrolchTransaction tx;

	/**
	 * Instantiate a new {@link Command}
	 * 
	 * @param container
	 *            the {@link ComponentContainer} to access components at runtime
	 * @param tx
	 */
	public StrolchPolicy(ComponentContainer container, StrolchTransaction tx) {
		this.container = container;
		this.tx = tx;
	}

	/**
	 * Allows the concrete {@link Command} implementation access to {@link StrolchComponent StrolchComponents} at
	 * runtime
	 * 
	 * @param clazz
	 *            the type of component to be returned
	 * 
	 * @return the component with the given {@link Class} which is registered on the {@link ComponentContainer}
	 * 
	 * @throws IllegalArgumentException
	 *             if the component with the given class does not exist
	 */
	protected <V> V getComponent(Class<V> clazz) throws IllegalArgumentException {
		return this.container.getComponent(clazz);
	}

	/**
	 * @return the container
	 */
	protected ComponentContainer getContainer() {
		return this.container;
	}

	/**
	 * Returns the {@link StrolchTransaction} bound to this {@link Command}'s runtime
	 * 
	 * @return the {@link StrolchTransaction} bound to this {@link Command}'s runtime
	 */
	protected StrolchTransaction tx() {
		return this.tx;
	}

	/**
	 * @see Command#undo()
	 */
	public abstract void undo();
}