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

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

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/*
 * Copyright 2014-2019 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 java.io.Serializable;

import org.springframework.core.MethodParameter;
import org.springframework.data.rest.core.mapping.ResourceMetadata;
import org.springframework.data.rest.webmvc.BaseUri;
import org.springframework.data.rest.webmvc.config.ResourceMetadataHandlerMethodArgumentResolver;
import org.springframework.data.rest.webmvc.spi.BackendIdConverter;
import org.springframework.data.rest.webmvc.spi.BackendIdConverter.DefaultIdConverter;
import org.springframework.data.rest.webmvc.util.UriUtils;
import org.springframework.plugin.core.PluginRegistry;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.support.WebDataBinderFactory;
import org.springframework.web.context.request.NativeWebRequest;
import org.springframework.web.method.support.HandlerMethodArgumentResolver;
import org.springframework.web.method.support.ModelAndViewContainer;

/**
 * {@link HandlerMethodArgumentResolver} to resolve entity ids for injection int handler method arguments annotated with
 * {@link BackendId}.
 *
 * @author Oliver Gierke
 */
public class BackendIdHandlerMethodArgumentResolver implements HandlerMethodArgumentResolver {

    private final PluginRegistry<BackendIdConverter, Class<?>> idConverters;
    private final ResourceMetadataHandlerMethodArgumentResolver resourceMetadataResolver;
    private final BaseUri baseUri;

    /**
     * Creates a new {@link BackendIdHandlerMethodArgumentResolver} for the given {@link BackendIdConverter}s and
     * {@link ResourceMetadataHandlerMethodArgumentResolver}.
     *
     * @param idConverters the {@link BackendIdConverter}s registered in the system, must not be {@literal null}..
     * @param resourceMetadataResolver the resolver to obtain {@link ResourceMetadata} from, must not be {@literal null}.
     * @param baseUri must not be {@literal null}.
     */
    public BackendIdHandlerMethodArgumentResolver(PluginRegistry<BackendIdConverter, Class<?>> idConverters,
            ResourceMetadataHandlerMethodArgumentResolver resourceMetadataResolver, BaseUri baseUri) {

        Assert.notNull(idConverters, "Id converters must not be null!");
        Assert.notNull(resourceMetadataResolver, "ResourceMetadata resolver must not be null!");
        Assert.notNull(baseUri, "BaseUri must not be null!");

        this.idConverters = idConverters;
        this.resourceMetadataResolver = resourceMetadataResolver;
        this.baseUri = baseUri;
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.web.method.support.HandlerMethodArgumentResolver#supportsParameter(org.springframework.core.MethodParameter)
     */
    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return parameter.hasParameterAnnotation(BackendId.class);
    }

    /*
     * (non-Javadoc)
     * @see org.springframework.web.method.support.HandlerMethodArgumentResolver#resolveArgument(org.springframework.core.MethodParameter, org.springframework.web.method.support.ModelAndViewContainer, org.springframework.web.context.request.NativeWebRequest, org.springframework.web.bind.support.WebDataBinderFactory)
     */
    @Override
    public Serializable resolveArgument(MethodParameter parameter, ModelAndViewContainer mavContainer,
            NativeWebRequest request, WebDataBinderFactory binderFactory) throws Exception {

        Class<?> parameterType = parameter.getParameterType();

        if (parameter.getMethodAnnotation(BackendId.class) != null && !parameterType.equals(Serializable.class)) {
            throw new IllegalArgumentException(
                    String.format("Method parameter for @%s must be of type %s! Got %s for method %s.",
                            BackendId.class.getSimpleName(), Serializable.class.getSimpleName(),
                            parameterType.getSimpleName(), parameter.getMethod()));
        }

        ResourceMetadata metadata = resourceMetadataResolver.resolveArgument(parameter, mavContainer, request,
                binderFactory);

        if (metadata == null) {
            throw new IllegalArgumentException("Could not obtain ResourceMetadata for request " + request);
        }

        BackendIdConverter pluginFor = idConverters.getPluginFor(metadata.getDomainType())
                .orElse(DefaultIdConverter.INSTANCE);
        String lookupPath = baseUri.getRepositoryLookupPath(request);
        String idSource = UriUtils.findMappingVariable("id", parameter.getMethod(), lookupPath);

        return StringUtils.hasText(idSource) //
                ? pluginFor.fromRequestId(idSource, metadata.getDomainType())
                : null;
    }
}