ControllerRelProvider.java

/*
 * Copyright 2013-2014 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.hateoas.mvc;

import org.springframework.core.annotation.AnnotationUtils;
import org.springframework.hateoas.ExposesResourceFor;
import org.springframework.hateoas.RelProvider;
import org.springframework.plugin.core.PluginRegistry;
import org.springframework.util.Assert;

/**
 * @author Oliver Gierke
 */
public class ControllerRelProvider implements RelProvider {

	private final Class<?> controllerType;
	private final Class<?> entityType;
	private final PluginRegistry<RelProvider, Class<?>> providers;

	public ControllerRelProvider(Class<?> controller, PluginRegistry<RelProvider, Class<?>> providers) {

		Assert.notNull(controller, "Controller must not be null!");

		ExposesResourceFor annotation = AnnotationUtils.findAnnotation(controller, ExposesResourceFor.class);
		Assert.notNull(annotation, "Controller must be annotated with ExposesResourceFor!");

		this.controllerType = controller;
		this.entityType = annotation.value();
		this.providers = providers;
	}

	/* 
	 * (non-Javadoc)
	 * @see org.springframework.hateoas.RelProvider#getRelForCollectionResource(java.lang.Class)
	 */
	@Override
	public String getCollectionResourceRelFor(Class<?> resource) {
		return providers.getPluginFor(entityType).getCollectionResourceRelFor(resource);
	}

	/* 
	 * (non-Javadoc)
	 * @see org.springframework.hateoas.RelProvider#getRelForSingleResource(java.lang.Class)
	 */
	@Override
	public String getItemResourceRelFor(Class<?> resource) {
		return providers.getPluginFor(entityType).getItemResourceRelFor(resource);
	}

	/* 
	 * (non-Javadoc)
	 * @see org.springframework.plugin.core.Plugin#supports(java.lang.Object)
	 */
	@Override
	public boolean supports(Class<?> delimiter) {
		return controllerType.equals(delimiter);
	}
}