/*
* Copyright 2016-2017 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.repository.query;
import java.util.Optional;
import org.springframework.data.domain.Example;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
/**
* Interface to allow execution of Query by Example {@link Example} instances.
*
* @param <T>
* @author Mark Paluch
* @author Christoph Strobl
* @since 1.12
*/
public interface QueryByExampleExecutor<T> {
/**
* Returns a single entity matching the given {@link Example} or {@literal null} if none was found.
*
* @param example can be {@literal null}.
* @return a single entity matching the given {@link Example} or {@link Optional#empty()} if none was found.
* @throws org.springframework.dao.IncorrectResultSizeDataAccessException if the Example yields more than one result.
*/
<S extends T> Optional<S> findOne(Example<S> example);
/**
* Returns all entities matching the given {@link Example}. In case no match could be found an empty {@link Iterable}
* is returned.
*
* @param example can be {@literal null}.
* @return all entities matching the given {@link Example}.
*/
<S extends T> Iterable<S> findAll(Example<S> example);
/**
* Returns all entities matching the given {@link Example} applying the given {@link Sort}. In case no match could be
* found an empty {@link Iterable} is returned.
*
* @param example can be {@literal null}.
* @param sort the {@link Sort} specification to sort the results by, must not be {@literal null}.
* @return all entities matching the given {@link Example}.
* @since 1.10
*/
<S extends T> Iterable<S> findAll(Example<S> example, Sort sort);
/**
* Returns a {@link Page} of entities matching the given {@link Example}. In case no match could be found, an empty
* {@link Page} is returned.
*
* @param example can be {@literal null}.
* @param pageable can be {@literal null}.
* @return a {@link Page} of entities matching the given {@link Example}.
*/
<S extends T> Page<S> findAll(Example<S> example, Pageable pageable);
/**
* Returns the number of instances matching the given {@link Example}.
*
* @param example the {@link Example} to count instances for, can be {@literal null}.
* @return the number of instances matching the {@link Example}.
*/
<S extends T> long count(Example<S> example);
/**
* Checks whether the data store contains elements that match the given {@link Example}.
*
* @param example the {@link Example} to use for the existence check, can be {@literal null}.
* @return {@literal true} if the data store contains elements that match the given {@link Example}.
*/
<S extends T> boolean exists(Example<S> example);
}