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

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Here is the source code for org.springframework.integration.transformer.AbstractTransformer.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 org.springframework.integration.context.IntegrationObjectSupport;
import org.springframework.messaging.Message;

/**
 * A base class for {@link Transformer} implementations.
 *
 * @author Mark Fisher
 * @author Oleg Zhurakousky
 */
public abstract class AbstractTransformer extends IntegrationObjectSupport implements Transformer {

    @Override
    public final Message<?> transform(Message<?> message) {
        try {
            Object result = this.doTransform(message);
            if (result == null) {
                return null;
            }
            return (result instanceof Message) ? (Message<?>) result
                    : getMessageBuilderFactory().withPayload(result).copyHeaders(message.getHeaders()).build();
        } catch (MessageTransformationException e) { // NOSONAR - catch and throw
            throw e;
        } catch (Exception e) {
            throw new MessageTransformationException(message, "failed to transform message", e);
        }
    }

    /**
     * Subclasses must implement this method to provide the transformation
     * logic. If the return value is itself a Message, it will be used as the
     * result. Otherwise, any non-null return value will be used as the payload
     * of the result Message.
     *
     * @param message The message.
     * @return The result of the transformation.
     */
    protected abstract Object doTransform(Message<?> message);

}