org.springframework.integration.transformer.MessageTransformingHandler.java Source code

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Here is the source code for org.springframework.integration.transformer.MessageTransformingHandler.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.transformer;

import java.util.Collection;

import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.context.Lifecycle;
import org.springframework.integration.handler.AbstractReplyProducingMessageHandler;
import org.springframework.integration.support.context.NamedComponent;
import org.springframework.messaging.Message;
import org.springframework.util.Assert;

/**
 * A reply-producing {@link org.springframework.messaging.MessageHandler}
 * that delegates to a
 * {@link Transformer} instance to modify the received {@link Message}
 * and sends the result to its output channel.
 *
 * @author Mark Fisher
 * @author Oleg Zhurakousky
 * @author Artem Bilan
 * @author Gary Russell
 */
public class MessageTransformingHandler extends AbstractReplyProducingMessageHandler implements Lifecycle {

    private final Transformer transformer;

    /**
     * Create a {@link MessageTransformingHandler} instance that delegates to
     * the provided {@link Transformer}.
     *
     * @param transformer The transformer.
     */
    public MessageTransformingHandler(Transformer transformer) {
        Assert.notNull(transformer, "transformer must not be null");
        this.transformer = transformer;
        this.setRequiresReply(true);
    }

    @Override
    public String getComponentType() {
        return (this.transformer instanceof NamedComponent) ? ((NamedComponent) this.transformer).getComponentType()
                : "transformer";
    }

    @Override
    public void addNotPropagatedHeaders(String... headers) {
        super.addNotPropagatedHeaders(headers);
        populateNotPropagatedHeadersIfAny();
    }

    @Override
    protected void doInit() {
        if (this.getBeanFactory() != null && this.transformer instanceof BeanFactoryAware) {
            ((BeanFactoryAware) this.transformer).setBeanFactory(this.getBeanFactory());
        }

        populateNotPropagatedHeadersIfAny();
    }

    private void populateNotPropagatedHeadersIfAny() {
        Collection<String> notPropagatedHeaders = getNotPropagatedHeaders();

        if (this.transformer instanceof AbstractMessageProcessingTransformer && !notPropagatedHeaders.isEmpty()) {
            ((AbstractMessageProcessingTransformer) this.transformer)
                    .setNotPropagatedHeaders(notPropagatedHeaders.toArray(new String[0]));
        }
    }

    @Override
    public void start() {
        if (this.transformer instanceof Lifecycle) {
            ((Lifecycle) this.transformer).start();
        }
    }

    @Override
    public void stop() {
        if (this.transformer instanceof Lifecycle) {
            ((Lifecycle) this.transformer).stop();
        }
    }

    @Override
    public boolean isRunning() {
        return !(this.transformer instanceof Lifecycle) || ((Lifecycle) this.transformer).isRunning();
    }

    @Override
    protected Object handleRequestMessage(Message<?> message) {
        try {
            return this.transformer.transform(message);
        } catch (Exception e) {
            if (e instanceof MessageTransformationException) {
                throw (MessageTransformationException) e;
            }
            throw new MessageTransformationException(message, "Failed to transform Message in " + this, e);
        }
    }

    @Override
    protected boolean shouldCopyRequestHeaders() {
        return false;
    }

}