org.springframework.data.rest.webmvc.support.PersistentEntityProjector Maven / Gradle / Ivy
/*
* Copyright 2014-2021 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
*
* https://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.rest.webmvc.support;
import java.util.function.Function;
import org.springframework.data.projection.ProjectionFactory;
import org.springframework.data.rest.core.mapping.ResourceMappings;
import org.springframework.data.rest.core.projection.ProjectionDefinitions;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
/**
* {@link Projector} looking up a projection by name for the given source type.
*
* @author Oliver Gierke
*/
public class PersistentEntityProjector extends DefaultExcerptProjector implements Projector {
private final ProjectionDefinitions definitions;
private final ProjectionFactory factory;
private final String projection;
/**
* Creates a new {@link PersistentEntityProjector} using the given {@link ProjectionDefinitions},
* {@link ProjectionFactory} and projection name.
*
* @param projectionDefinitions must not be {@literal null}.
* @param factory must not be {@literal null}.
* @param projection can be empty.
*/
public PersistentEntityProjector(ProjectionDefinitions projectionDefinitions, ProjectionFactory factory,
String projection, ResourceMappings mappings) {
super(factory, mappings);
Assert.notNull(projectionDefinitions, "ProjectionDefinitions must not be null!");
Assert.notNull(factory, "ProjectionFactory must not be null!");
this.factory = factory;
this.definitions = projectionDefinitions;
this.projection = projection;
}
/*
* (non-Javadoc)
* @see org.springframework.data.rest.webmvc.support.Projector#project(java.lang.Object)
*/
public Object project(Object source) {
return projectWithDefault(source, Function.identity());
}
/*
* (non-Javadoc)
* @see org.springframework.data.rest.webmvc.support.DefaultExcerptProjector#projectExcerpt(java.lang.Object)
*/
@Override
public Object projectExcerpt(Object source) {
return projectWithDefault(source, PersistentEntityProjector.super::projectExcerpt);
}
/**
* Creates the projection for the given source instance falling back to the given {@link Function} if no explicit
* projection is selected.
*
* @param source must not be {@literal null}.
* @param converter must not be {@literal null}.
* @return
*/
private Object projectWithDefault(Object source, Function converter) {
Assert.notNull(source, "Projection source must not be null!");
Assert.notNull(converter, "Converter must not be null!");
if (!StringUtils.hasText(projection)) {
return converter.apply(source);
}
Class projectionType = definitions.getProjectionType(source.getClass(), projection);
return projectionType == null ? converter.apply(source) : factory.createProjection(projectionType, source);
}
}