org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.java Source code

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Here is the source code for org.springframework.data.rest.webmvc.PersistentEntityResourceAssembler.java

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/*
 * Copyright 2013-2019 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;

import lombok.NonNull;
import lombok.RequiredArgsConstructor;

import org.springframework.data.mapping.PersistentEntity;
import org.springframework.data.mapping.context.PersistentEntities;
import org.springframework.data.rest.core.support.SelfLinkProvider;
import org.springframework.data.rest.webmvc.PersistentEntityResource.Builder;
import org.springframework.data.rest.webmvc.mapping.Associations;
import org.springframework.data.rest.webmvc.support.Projector;
import org.springframework.hateoas.Link;
import org.springframework.hateoas.server.RepresentationModelAssembler;
import org.springframework.hateoas.server.core.EmbeddedWrapper;
import org.springframework.hateoas.server.core.EmbeddedWrappers;
import org.springframework.util.Assert;

/**
 * {@link ResourceAssembler} to create {@link PersistentEntityResource}s for arbitrary domain objects.
 *
 * @author Oliver Gierke
 */
@RequiredArgsConstructor
public class PersistentEntityResourceAssembler
        implements RepresentationModelAssembler<Object, PersistentEntityResource> {

    private final @NonNull PersistentEntities entities;
    private final @NonNull Projector projector;
    private final @NonNull Associations associations;
    private final @NonNull SelfLinkProvider linkProvider;
    private final @NonNull EmbeddedWrappers wrappers = new EmbeddedWrappers(false);

    /*
     * (non-Javadoc)
     * @see org.springframework.hateoas.server.RepresentationModelAssembler#toModel(java.lang.Object)
     */
    @Override
    public PersistentEntityResource toModel(Object instance) {

        Assert.notNull(instance, "Entity instance must not be null!");
        return wrap(projector.projectExcerpt(instance), instance).build();
    }

    /**
     * Returns the full object as {@link PersistentEntityResource} using the underlying {@link Projector}.
     *
     * @param instance must not be {@literal null}.
     * @return
     */
    public PersistentEntityResource toFullResource(Object instance) {

        Assert.notNull(instance, "Entity instance must not be null!");
        return wrap(projector.project(instance), instance).build();
    }

    private Builder wrap(Object instance, Object source) {

        PersistentEntity<?, ?> entity = entities.getRequiredPersistentEntity(source.getClass());

        return PersistentEntityResource.build(instance, entity).//
                withEmbedded(getEmbeddedResources(source)).//
                withLink(getExpandedSelfLink(source)).//
                withLink(linkProvider.createSelfLinkFor(source));
    }

    /**
     * Returns the embedded resources to render. This will add an {@link RelatedResource} for linkable associations if
     * they have an excerpt projection registered.
     *
     * @param instance must not be {@literal null}.
     * @return
     */
    private Iterable<EmbeddedWrapper> getEmbeddedResources(Object instance) {
        return new EmbeddedResourcesAssembler(entities, associations, projector).getEmbeddedResources(instance);
    }

    /**
     * Creates the self link for the given domain instance, with no templated parameters.
     *
     * @param instance must be a managed entity, not {@literal null}.
     * @return
     */
    Link getExpandedSelfLink(Object instance) {
        return linkProvider.createSelfLinkFor(instance).withSelfRel().expand();
    }
}