org.springframework.integration.file.transformer.AbstractFilePayloadTransformer.java Source code

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Here is the source code for org.springframework.integration.file.transformer.AbstractFilePayloadTransformer.java

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/*
 * Copyright 2002-2009 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
 *
 *      http://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.file.transformer;

import java.io.File;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.springframework.integration.Message;
import org.springframework.integration.MessagingException;
import org.springframework.integration.file.FileHeaders;
import org.springframework.integration.support.MessageBuilder;
import org.springframework.integration.transformer.Transformer;
import org.springframework.util.Assert;

/**
 * Base class for transformers that convert a File payload.
 * 
 * @author Mark Fisher
 */
public abstract class AbstractFilePayloadTransformer<T> implements Transformer {

    private final Log logger = LogFactory.getLog(this.getClass());

    private volatile boolean deleteFiles;

    /**
     * Specify whether to delete the File after transformation.
     * Default is <em>false</em>.
     */
    public void setDeleteFiles(boolean deleteFiles) {
        this.deleteFiles = deleteFiles;
    }

    public final Message<?> transform(Message<?> message) {
        try {
            Assert.notNull(message, "Message must not be null");
            Object payload = message.getPayload();
            Assert.notNull(payload, "Mesasge payload must not be null");
            Assert.isInstanceOf(File.class, payload, "Message payload must be of type [java.io.File]");
            File file = (File) payload;
            T result = this.transformFile(file);
            Message<?> transformedMessage = MessageBuilder.withPayload(result).copyHeaders(message.getHeaders())
                    .setHeaderIfAbsent(FileHeaders.ORIGINAL_FILE, file)
                    .setHeaderIfAbsent(FileHeaders.FILENAME, file.getName()).build();
            if (this.deleteFiles) {
                if (!file.delete() && this.logger.isWarnEnabled()) {
                    this.logger.warn("failed to delete File '" + file + "'");
                }
            }
            return transformedMessage;
        } catch (Exception e) {
            throw new MessagingException(message, "failed to transform File Message", e);
        }
    }

    /**
     * Subclasses must implement this method to transform the File contents.
     */
    protected abstract T transformFile(File file) throws Exception;

}