org.springframework.integration.support.converter.MapMessageConverter.java Source code

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Here is the source code for org.springframework.integration.support.converter.MapMessageConverter.java

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/*
 * Copyright 2002-2019 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.integration.support.converter;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.integration.support.AbstractIntegrationMessageBuilder;
import org.springframework.integration.support.DefaultMessageBuilderFactory;
import org.springframework.integration.support.MessageBuilderFactory;
import org.springframework.integration.support.utils.IntegrationUtils;
import org.springframework.lang.Nullable;
import org.springframework.messaging.Message;
import org.springframework.messaging.MessageHeaders;
import org.springframework.messaging.converter.MessageConverter;
import org.springframework.util.Assert;

/**
 * Converts to/from a Map with 2 keys ('headers' and 'payload').
 *
 * @author Gary Russell
 * @author Artem Bilan
 *
 * @since 3.0
 *
 */
public class MapMessageConverter implements MessageConverter, BeanFactoryAware {

    private volatile String[] headerNames;

    private volatile boolean filterHeadersInToMessage;

    private volatile BeanFactory beanFactory;

    private volatile MessageBuilderFactory messageBuilderFactory = new DefaultMessageBuilderFactory();

    private volatile boolean messageBuilderFactorySet;

    @Override
    public final void setBeanFactory(BeanFactory beanFactory) {
        this.beanFactory = beanFactory;
    }

    protected MessageBuilderFactory getMessageBuilderFactory() {
        if (!this.messageBuilderFactorySet) {
            if (this.beanFactory != null) {
                this.messageBuilderFactory = IntegrationUtils.getMessageBuilderFactory(this.beanFactory);
            }
            this.messageBuilderFactorySet = true;
        }
        return this.messageBuilderFactory;
    }

    /**
     * Headers to be converted in {@link #fromMessage(Message, Class)}.
     * {@link #toMessage(Object, MessageHeaders)} will populate all headers found in
     * the map, unless {@link #filterHeadersInToMessage} is true.
     *
     * @param headerNames The header names.
     */
    public void setHeaderNames(String... headerNames) {
        Assert.notEmpty(headerNames, "at least one header name is required");
        this.headerNames = Arrays.copyOf(headerNames, headerNames.length);
    }

    /**
     * By default all headers on Map passed to {@link #toMessage(Object, MessageHeaders)}
     * will be mapped. Set this property
     * to 'true' if you wish to limit the inbound headers to those in
     * the #headerNames.
     *
     * @param filterHeadersInToMessage true if the headers should be filtered.
     */
    public void setFilterHeadersInToMessage(boolean filterHeadersInToMessage) {
        this.filterHeadersInToMessage = filterHeadersInToMessage;
    }

    @Nullable
    @Override
    public Message<?> toMessage(Object object, @Nullable MessageHeaders messageHeaders) {
        Assert.isInstanceOf(Map.class, object, "This converter expects a Map");
        @SuppressWarnings("unchecked")
        Map<String, ?> map = (Map<String, ?>) object;
        Object payload = map.get("payload");
        Assert.notNull(payload, "'payload' entry cannot be null");
        AbstractIntegrationMessageBuilder<?> messageBuilder = getMessageBuilderFactory().withPayload(payload);
        @SuppressWarnings("unchecked")
        Map<String, ?> headers = (Map<String, ?>) map.get("headers");
        if (headers != null) {
            if (this.filterHeadersInToMessage) {
                headers.keySet().retainAll(Arrays.asList(this.headerNames));
            }
            messageBuilder.copyHeaders(headers);
        }
        return messageBuilder.copyHeadersIfAbsent(messageHeaders).build();
    }

    @Nullable
    @Override
    public Object fromMessage(Message<?> message, Class<?> clazz) {
        Map<String, Object> map = new HashMap<>();
        map.put("payload", message.getPayload());
        Map<String, Object> headers = new HashMap<>();
        for (String headerName : this.headerNames) {
            Object header = message.getHeaders().get(headerName);
            if (header != null) {
                headers.put(headerName, header);
            }
        }
        map.put("headers", headers);
        return map;
    }

}