QueryExtractor.java

/*
 * Copyright 2008-2011 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.data.jpa.provider;

import javax.persistence.Query;

/**
 * Interface to hide different implementations to extract the original JPA query string from a {@link Query}.
 * 
 * @author Oliver Gierke
 */
public interface QueryExtractor {

	/**
	 * Reverse engineers the query string from the {@link Query} object. This requires provider specific API as JPA does
	 * not provide access to the underlying query string as soon as one has created a {@link Query} instance of it.
	 * 
	 * @param query
	 * @return the query string representing the query or {@literal null} if resolving is not possible.
	 */
	String extractQueryString(Query query);

	/**
	 * Returns whether the extractor is able to extract the original query string from a given {@link Query}.
	 * 
	 * @return
	 */
	boolean canExtractQuery();
}