org.springframework.data.rest.webmvc.support.DefaultExcerptProjector.java Source code

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

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/*
 * Copyright 2016-2019 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.support;

import lombok.RequiredArgsConstructor;

import java.util.Optional;

import org.springframework.data.projection.ProjectionFactory;
import org.springframework.data.rest.core.mapping.ResourceMappings;
import org.springframework.data.rest.core.mapping.ResourceMetadata;
import org.springframework.util.Assert;

/**
 * {@link DefaultedPageable} implementation of {@link ExcerptProjector} that uses the given {@link ProjectionFactory}
 * and considers the given {@link ResourceMappings}.
 *
 * @author Oliver Gierke
 * @since 2.5
 */
@RequiredArgsConstructor
public class DefaultExcerptProjector implements ExcerptProjector {

    private final ProjectionFactory factory;
    private final ResourceMappings mappings;

    /*
     * (non-Javadoc)
     * @see org.springframework.data.rest.webmvc.support.ExcerptProjector#projectExcerpt(java.lang.Object)
     */
    @Override
    public Object projectExcerpt(Object source) {

        Assert.notNull(source, "Projection source must not be null!");

        ResourceMetadata metadata = mappings.getMetadataFor(source.getClass());

        return Optional.ofNullable(metadata) //
                .flatMap(ResourceMetadata::getExcerptProjection) //
                .filter(it -> !it.equals(source.getClass())) //
                .<Object>map(it -> factory.createProjection(it, source)) //
                .orElse(source);

    }

    /*
     * (non-Javadoc)
     * @see org.springframework.data.rest.webmvc.support.ExcerptProjector#hasExcerptProjection(java.lang.Class)
     */
    @Override
    public boolean hasExcerptProjection(Class<?> type) {

        ResourceMetadata metadata = mappings.getMetadataFor(type);
        return metadata == null ? false : metadata.getExcerptProjection() != null;
    }
}