org.springframework.web.method.annotation.RequestHeaderMethodArgumentResolver.java Source code

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Here is the source code for org.springframework.web.method.annotation.RequestHeaderMethodArgumentResolver.java

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/*
 * Copyright 2002-2018 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.web.method.annotation;

import java.util.Map;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.bind.MissingRequestHeaderException;
import org.springframework.web.bind.ServletRequestBindingException;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.context.request.NativeWebRequest;

/**
 * Resolves method arguments annotated with {@code @RequestHeader} except for
 * {@link Map} arguments. See {@link RequestHeaderMapMethodArgumentResolver} for
 * details on {@link Map} arguments annotated with {@code @RequestHeader}.
 *
 * <p>An {@code @RequestHeader} is a named value resolved from a request header.
 * It has a required flag and a default value to fall back on when the request
 * header does not exist.
 *
 * <p>A {@link WebDataBinder} is invoked to apply type conversion to resolved
 * request header values that don't yet match the method parameter type.
 *
 * @author Arjen Poutsma
 * @author Rossen Stoyanchev
 * @since 3.1
 */
public class RequestHeaderMethodArgumentResolver extends AbstractNamedValueMethodArgumentResolver {

    /**
     * Create a new {@link RequestHeaderMethodArgumentResolver} instance.
     * @param beanFactory a bean factory to use for resolving  ${...}
     * placeholder and #{...} SpEL expressions in default values;
     * or {@code null} if default values are not expected to have expressions
     */
    public RequestHeaderMethodArgumentResolver(@Nullable ConfigurableBeanFactory beanFactory) {
        super(beanFactory);
    }

    @Override
    public boolean supportsParameter(MethodParameter parameter) {
        return (parameter.hasParameterAnnotation(RequestHeader.class)
                && !Map.class.isAssignableFrom(parameter.nestedIfOptional().getNestedParameterType()));
    }

    @Override
    protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) {
        RequestHeader ann = parameter.getParameterAnnotation(RequestHeader.class);
        Assert.state(ann != null, "No RequestHeader annotation");
        return new RequestHeaderNamedValueInfo(ann);
    }

    @Override
    @Nullable
    protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request)
            throws Exception {
        String[] headerValues = request.getHeaderValues(name);
        if (headerValues != null) {
            return (headerValues.length == 1 ? headerValues[0] : headerValues);
        } else {
            return null;
        }
    }

    @Override
    protected void handleMissingValue(String name, MethodParameter parameter)
            throws ServletRequestBindingException {
        throw new MissingRequestHeaderException(name, parameter);
    }

    private static final class RequestHeaderNamedValueInfo extends NamedValueInfo {

        private RequestHeaderNamedValueInfo(RequestHeader annotation) {
            super(annotation.name(), annotation.required(), annotation.defaultValue());
        }
    }

}