/* 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.activiti.engine.query;
import java.util.List;
/**
* Describes basic methods for querying.
*
* @author Frederik Heremans
*/
public interface Query<T extends Query< ? , ? >, U extends Object> {
/**
* Order the results ascending on the given property as defined in this
* class (needs to come after a call to one of the orderByXxxx methods).
*/
T asc();
/**
* Order the results descending on the given property as defined in this
* class (needs to come after a call to one of the orderByXxxx methods).
*/
T desc();
/** Executes the query and returns the number of results */
long count();
/**
* Executes the query and returns the resulting entity or null if no
* entity matches the query criteria.
* @throws ActivitiException when the query results in more than one
* entities.
*/
U singleResult();
/** Executes the query and get a list of entities as the result. */
List<U> list();
/** Executes the query and get a list of entities as the result. */
List<U> listPage(int firstResult, int maxResults);
}