/*
 * Copyright 2005-2014 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.ws.client.support.destination;

import java.net.URI;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * Abstract base class for {@link DestinationProvider} implementations that cache destination URI.
 *
 * <p>Caching can be disabled by setting the {@link #setCache(boolean) cache} property to {@code false}; forcing a
 * destination lookup for every call.
 *
 * @author Arjen Poutsma
 * @since 1.5.4
 */
public abstract class AbstractCachingDestinationProvider implements DestinationProvider {

	/** Logger available to subclasses. */
	protected final Log logger = LogFactory.getLog(getClass());

	private URI cachedUri;

	private boolean cache = true;

	/**
	 * Set whether to cache resolved destinations. Default is {@code true}. This flag can be turned off to
	 * re-lookup a destination for each operation, which allows for hot restarting of destinations. This is mainly
	 * useful during development.
	 */
	public void setCache(boolean cache) {
		this.cache = cache;
	}

	@Override
	public final URI getDestination() {
		if (cache) {
			if (cachedUri == null) {
				cachedUri = lookupDestination();
			}
			return cachedUri;
		}
		else {
			return lookupDestination();
		}
	}

	/**
	 * Abstract template method that looks up the URI.
	 *
	 * <p>If {@linkplain #setCache(boolean) caching}  is enabled, this method will only be called once.
	 *
	 * @return the destination URI
	 */
	protected abstract URI lookupDestination();
}