/*
* Copyright 2013-2016 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.core.support;
import static java.util.Arrays.*;
import static org.springframework.data.util.Optionals.*;
import java.lang.reflect.Method;
import java.util.Optional;
import java.util.function.Supplier;
import java.util.stream.Stream;
import org.springframework.core.BridgeMethodResolver;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.core.CrudMethods;
import org.springframework.data.repository.core.RepositoryMetadata;
import org.springframework.data.util.Optionals;
import org.springframework.data.util.Pair;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ReflectionUtils;
/**
* Default implementation to discover CRUD methods based on the given {@link RepositoryMetadata}. Will detect methods
* exposed in {@link CrudRepository} but also hand crafted CRUD methods that are signature compatible with the ones on
* {@link CrudRepository}.
*
* @author Oliver Gierke
* @author Thomas Darimont
* @since 1.6
*/
public class DefaultCrudMethods implements CrudMethods {
private static final String FIND_ONE = "findById";
private static final String SAVE = "save";
private static final String FIND_ALL = "findAll";
private static final String DELETE = "delete";
private static final String DELETE_BY_ID = "deleteById";
private final Optional<Method> findAllMethod;
private final Optional<Method> findOneMethod;
private final Optional<Method> saveMethod;
private final Optional<Method> deleteMethod;
/**
* Creates a new {@link DefaultCrudMethods} using the given {@link RepositoryMetadata}.
*
* @param metadata must not be {@literal null}.
*/
public DefaultCrudMethods(RepositoryMetadata metadata) {
Assert.notNull(metadata, "RepositoryInformation must not be null!");
this.findOneMethod = selectMostSuitableFindOneMethod(metadata);
this.findAllMethod = selectMostSuitableFindAllMethod(metadata);
this.deleteMethod = selectMostSuitableDeleteMethod(metadata);
this.saveMethod = selectMostSuitableSaveMethod(metadata);
}
/**
* The most suitable save method is selected as follows: We prefer
* <ol>
* <li>a {@link RepositoryMetadata#getDomainType()} as first parameter over</li>
* <li>an {@link Object} as first parameter.</li>
* </ol>
*
* @param metadata must not be {@literal null}.
* @return the most suitable method or {@literal null} if no method could be found.
*/
private static Optional<Method> selectMostSuitableSaveMethod(RepositoryMetadata metadata) {
return asList(metadata.getDomainType(), Object.class).stream()//
.flatMap(it -> toStream(findMethod(metadata.getRepositoryInterface(), SAVE, it)))//
.flatMap(it -> toStream(getMostSpecificMethod(it, metadata.getRepositoryInterface())))//
.findFirst();
}
/**
* The most suitable delete method is selected as follows: We prefer
* <ol>
* <li>a {@link RepositoryMetadata#getDomainType()} as first parameter over</li>
* <li>a {@link RepositoryMetadata#getIdType()} as first parameter over</li>
* <li>a {@link Object} as first parameter over</li>
* <li>an {@link Iterable} as first parameter.</li>
* </ol>
*
* @param metadata must not be {@literal null}.
* @return the most suitable method or {@literal null} if no method could be found.
*/
private static Optional<Method> selectMostSuitableDeleteMethod(RepositoryMetadata metadata) {
Stream<Pair<String, Class<?>>> source = Stream.of(//
Pair.of(DELETE, metadata.getDomainType()), //
Pair.of(DELETE_BY_ID, metadata.getIdType()), //
Pair.of(DELETE, Object.class), //
Pair.of(DELETE_BY_ID, Object.class), //
Pair.of(DELETE, Iterable.class));
Class<?> repositoryInterface = metadata.getRepositoryInterface();
return source//
.flatMap(it -> toStream(findMethod(repositoryInterface, it.getFirst(), it.getSecond())))//
.flatMap(it -> toStream(getMostSpecificMethod(it, repositoryInterface)))//
.findFirst();
}
/**
* The most suitable findAll method is selected as follows: We prefer
* <ol>
* <li>a {@link Pageable} as first parameter over</li>
* <li>a {@link Sort} as first parameter over</li>
* <li>no parameters.</li>
* </ol>
*
* @param metadata must not be {@literal null}.
* @return the most suitable method or {@literal null} if no method could be found.
*/
private static Optional<Method> selectMostSuitableFindAllMethod(RepositoryMetadata metadata) {
Class<?> repositoryInterface = metadata.getRepositoryInterface();
Supplier<Optional<Method>> withPageableOrSort = () -> Stream.of(Pageable.class, Sort.class)//
.flatMap(it -> toStream(findMethod(repositoryInterface, FIND_ALL, it)))//
.flatMap(it -> toStream(getMostSpecificMethod(it, repositoryInterface)))//
.findFirst();
Supplier<Optional<Method>> withoutParameter = () -> findMethod(repositoryInterface, FIND_ALL)//
.flatMap(it -> getMostSpecificMethod(it, repositoryInterface));
return firstNonEmpty(withPageableOrSort, withoutParameter);
}
/**
* The most suitable {@code findById} method is selected as follows: We prefer
* <ol>
* <li>a {@link RepositoryMetadata#getIdType()} as first parameter over</li>
* <li>a {@link Object} as first parameter</li>
* </ol>
*
* @param metadata must not be {@literal null}.
* @return the most suitable method or {@literal null} if no method could be found.
*/
private static Optional<Method> selectMostSuitableFindOneMethod(RepositoryMetadata metadata) {
return asList(metadata.getIdType(), Object.class).stream()//
.flatMap(it -> toStream(findMethod(metadata.getRepositoryInterface(), FIND_ONE, it)))//
.flatMap(it -> toStream(getMostSpecificMethod(it, metadata.getRepositoryInterface())))//
.findFirst();
}
/**
* Looks up the most specific method for the given method and type and returns an accessible version of discovered
* {@link Method} if found.
*
* @param method
* @param type
* @see ClassUtils#getMostSpecificMethod(Method, Class)
* @return
*/
private static Optional<Method> getMostSpecificMethod(Method method, Class<?> type) {
return Optionals.toStream(Optional.ofNullable(ClassUtils.getMostSpecificMethod(method, type)))//
.map(it -> BridgeMethodResolver.findBridgedMethod(it))//
.peek(it -> ReflectionUtils.makeAccessible(it))//
.findFirst();
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#getSaveMethod()
*/
@Override
public Optional<Method> getSaveMethod() {
return saveMethod;
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#hasSaveMethod()
*/
@Override
public boolean hasSaveMethod() {
return saveMethod.isPresent();
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#getFindAllMethod()
*/
@Override
public Optional<Method> getFindAllMethod() {
return findAllMethod;
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#hasFindAllMethod()
*/
@Override
public boolean hasFindAllMethod() {
return findAllMethod.isPresent();
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#getFindOneMethod()
*/
@Override
public Optional<Method> getFindOneMethod() {
return findOneMethod;
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#hasFindOneMethod()
*/
@Override
public boolean hasFindOneMethod() {
return findOneMethod.isPresent();
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#hasDelete()
*/
@Override
public boolean hasDelete() {
return this.deleteMethod.isPresent();
}
/*
* (non-Javadoc)
* @see org.springframework.data.repository.core.support.CrudMethods#getDeleteMethod()
*/
@Override
public Optional<Method> getDeleteMethod() {
return this.deleteMethod;
}
private static Optional<Method> findMethod(Class<?> type, String name, Class<?>... parameterTypes) {
return Optional.ofNullable(ReflectionUtils.findMethod(type, name, parameterTypes));
}
}