Mule transformer to extract a zip file into a List of InputStream

1UnzipTransformer.java

/* 
 * Licensed to the soi-toolkit project under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The soi-toolkit project licenses this file to You 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 com.ullgren.mule.transformer.compression;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

import org.mule.api.MuleMessage;
import org.mule.api.transformer.TransformerException;
import org.mule.config.i18n.MessageFactory;
import org.mule.routing.filters.WildcardFilter;
import org.mule.transformer.AbstractMessageTransformer;
import org.mule.transformer.types.SimpleDataType;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Extracts the files in a zip-file and places them in a {@link List} of {@link InputStream}s.
 * Expects the zip-file as byte-array or an inputStream.
 * 
 * This class was initially been copied from the SOI Toolkit project (http://code.google.com/p/soi-toolkit/), updated to Mule 3 and added support for multiple files.
 * 
 * @author magnus larsson
 * @author Pontus Ullgren
 */
public class UnzipTransformer extends AbstractMessageTransformer {

	private static final Logger log = LoggerFactory.getLogger(UnzipTransformer.class);

	private WildcardFilter filter = new WildcardFilter("*");
	
	private int BUFFER = 2048;

	public UnzipTransformer() {
		registerSourceType(new SimpleDataType<Object>(InputStream.class));
		registerSourceType(new SimpleDataType<Object>(byte[].class));
	    setReturnDataType(new SimpleDataType<Object>(List.class));
	}

	public void setFilenamePattern(String pattern) {
		filter.setPattern(pattern);
	}

	public String getFilenamePattern() {
		return filter.getPattern();
	}
	
	@Override
	public Object transformMessage(MuleMessage message, String outputEncoding) throws TransformerException {
		Object payload = message.getPayload();
		
		List<InputStream> resultList = new ArrayList<InputStream>();

		InputStream is = null;
		if (payload instanceof InputStream) {
			is = (InputStream)payload;

		} else if (payload instanceof byte[]) {
			is = new ByteArrayInputStream((byte[]) payload);

		} else {
			throw new RuntimeException("Unknown payload type: " + payload.getClass().getName());
		}

		ZipInputStream zis = new ZipInputStream(is);
		ZipEntry entry = null;
		try {
			while ((entry = zis.getNextEntry()) != null) {
				String name = entry.getName();

				// Skip folders...
				if (entry.isDirectory()) {
					log.debug("skip folder " + name);
					continue;
				}

				// Does the file pass the filename-filter?
				if (!filter.accept(name)) {
					log.debug("skip file " + name + " did not match filename pattern: " + filter.getPattern());
					continue;
				}

				int lastDirSep = name.lastIndexOf('/');
				if (lastDirSep != -1) {
					log.debug("unzip strips zip-folderpath " + name.substring(0, lastDirSep));
					name = name.substring(lastDirSep + 1);
				}
				
				File tempFile = File.createTempFile("mule", "tmp");
				
				// write the current file to disk
				FileOutputStream fos = new FileOutputStream(tempFile);
				    	            
				// read and write until last byte is encountered
				byte[] buf = new byte[BUFFER];
				int readBytes = 0;
				while( (readBytes = zis.read(buf,0, BUFFER)) != -1) {
					fos.write(buf,0, readBytes);
				}
				zis.closeEntry();
			        fos.close();
	            
				resultList.add(new DeleteOnCloseFileInputStream(tempFile));
			}
                        // ZipInputStream#close() will also close the underlying input stream.
			zis.close();
	                
		} catch (IOException ioException) {
			throw new TransformerException(MessageFactory.createStaticMessage("Failed to uncompress file."), this, ioException);
		} catch (Exception e) {
			throw new TransformerException(MessageFactory.createStaticMessage("Failed to uncompress file."), this, e);
		}

		return resultList;
	}
}

2DeleteOnCloseFileInputStream.java

package com.ullgren.mule.transformer.compression;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class DeleteOnCloseFileInputStream extends FileInputStream {
	private File file;
	
	public DeleteOnCloseFileInputStream(File file) throws FileNotFoundException {
		super(file);
		this.file = file;
	}
	
	 public void close() throws IOException {
	       try {
	          super.close();
	       } finally {
	          if(file != null) {
	             file.delete();
	             file = null;
	         }
	       }
	   }
}