/*
 * Copyright 2002-2015 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.web.servlet.resource;

import org.springframework.core.io.Resource;

/**
 * An extension of {@link VersionPathStrategy} that adds a method
 * to determine the actual version of a {@link Resource}.
 *
 * @author Brian Clozel
 * @author Rossen Stoyanchev
 * @since 4.1
 * @see VersionResourceResolver
*/
public interface VersionStrategy extends VersionPathStrategy {

	/**
	 * Determine the version for the given resource.
	 * @param resource the resource to check
	 * @return the version (never {@code null})
	 */
	String getResourceVersion(Resource resource);

}
