Compressing and decompressing files using a AEM Forms on JEE Custom DSC compressing-decompressing-files

/*
 * Custom DSC : ZIP Utility
 * Purpose: This is a LiveCycle ES2 custom component used to Compress & Decompress List of Documents
 * Author: Nithiyanandam Dharmadass
 * Organization: Ministry of Finance, Kingdom of Bahrain
 * Last modified Date: 18/Apr/2011
 */
package nith.lces2.dsc;

import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import com.adobe.idp.Document;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.ZipOutputStream;

public class ZIPService {

    static final int BUFFER = 2048; // 2MB buffer size

    public java.util.List UnzipDocument(com.adobe.idp.Document zipDocument) throws Exception {
        ZipInputStream zis = new ZipInputStream(zipDocument.getInputStream());

        ZipEntry zipFile;

        List resultList = new ArrayList();

        while ((zipFile = zis.getNextEntry()) != null) {

            ByteArrayOutputStream byteArrayOutStream = new ByteArrayOutputStream();

            int count;  // an int variable to hold the number of bytes read from input stream
            byte data[] = new byte[BUFFER];
            while ((count = zis.read(data, 0, BUFFER)) != -1) {
                byteArrayOutStream.write(data, 0, count);   // write to byte array
            }

            com.adobe.idp.Document unzippedDoc = new Document(byteArrayOutStream.toByteArray());  // create an idp document
            unzippedDoc.setAttribute("file", zipFile.getName());
            unzippedDoc.setAttribute("wsfilename", zipFile.getName());  // update the wsfilename attribute
            resultList.add(unzippedDoc);
        }
        return resultList;  // List of uncompressed documents
    }

    public com.adobe.idp.Document ZipDocuments(java.util.List listOfDocuments,java.lang.String zipFileName) throws Exception {

        if (listOfDocuments == null || listOfDocuments.size() == 0) {
            return null;
        }

        ByteArrayOutputStream byteArrayOutStream = new ByteArrayOutputStream();
        ZipOutputStream zos = new ZipOutputStream(byteArrayOutStream);  // ZIP Output Stream

        for (int i = 0; i < listOfDocuments.size(); i++) {
            Document doc = (Document) listOfDocuments.get(i);
            InputStream docInputStream = doc.getInputStream();
            ZipEntry zipEntry = new ZipEntry(doc.getAttribute("file").toString());
            zos.putNextEntry(zipEntry);
            int count;
            byte data[] = new byte[BUFFER];
            while ((count = docInputStream.read(data, 0, BUFFER)) != -1) {
                zos.write(data, 0, count);  // Read document content and add to zip entry
            }
            zos.closeEntry();
        }
        zos.flush();
        zos.close();

        Document zippedDoc = new Document(byteArrayOutStream.toByteArray());
        if(zipFileName==null || zipFileName.equals(""))
        {
            zipFileName = "CompressedList.zip";
        }
        zippedDoc.setAttribute("file", zipFileName);
        return zippedDoc;
    }
}