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Java file server with SMB, FTP/FTPS and NFS support, virtual filesystems, database filesystems
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/*
 * Copyright (C) 2006-2010 Alfresco Software Limited.
 *
 * This file is part of Alfresco
 *
 * Alfresco is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Alfresco is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with Alfresco. If not, see .
 */

package org.filesys.sample;

import java.security.MessageDigest;

import org.filesys.debug.Debug;
import org.filesys.server.filesys.DiskDeviceContext;
import org.filesys.server.filesys.cache.FileState;
import org.filesys.server.filesys.loader.FileProcessor;
import org.filesys.server.filesys.loader.FileSegment;
import org.filesys.util.HexDump;

/**
 * MD5 Checksum File Processor Class
 *
 * Calculate an MD5 checksum for a file before it is stored and save the result in a database field.
 *
 * @author gkspencer
 */
public class Md5SumFileProcessor implements FileProcessor {

    //	Flag to indicate if the filesystem table has an MD5Sum field
    private boolean m_md5field = true;

    /**
     * Process a cached file just before it is to be stored.
     *
     * @param context DiskDeviceContext
     * @param state   FileState
     * @param segment FileSegment
     */
    public void processStoredFile(DiskDeviceContext context, FileState state, FileSegment segment) {

        //	Calculate an MD5 checksum for the file
        String md5sum = calculateMd5Checksum(segment);
        Debug.println("## StoreFile file=" + state.getPath() + ", fid=" + state.getFileId() + ", temp=" + segment.getTemporaryFile() +
                ", MD5=" + md5sum);
    }

    /**
     * Process a cached file just after being loaded.
     *
     * @param context DiskDeviceContext
     * @param state   FileState
     * @param segment FileSegment
     */
    public void processLoadedFile(DiskDeviceContext context, FileState state, FileSegment segment) {
    }

    /**
     * Calculate an MD5 checksum for a file
     *
     * @param segment FileSegment
     * @return String
     */
    protected final String calculateMd5Checksum(FileSegment segment) {

        MessageDigest md5 = null;
        String checksum = null;

        try {

            //	Get an MD5 message digest
            md5 = MessageDigest.getInstance("MD5");

            //	Create a buffer for reading the file
            byte[] inbuf = new byte[512];
            long fileOff = 0L;
            int rdlen = segment.readBytes(inbuf, inbuf.length, 0, fileOff);

            //	Read the file and calculate the MD5 checksum
            while (rdlen > 0) {

                //	Update the MD5 checksum
                md5.update(inbuf, 0, rdlen);

                //	Update the file offset
                fileOff += rdlen;

                //	Read another block of data
                rdlen = segment.readBytes(inbuf, inbuf.length, 0, fileOff);
            }

            //	Get the final MD5 checksum
            byte[] md5sum = md5.digest();

            //	Convert the checksum to a hex string
            checksum = HexDump.hexString(md5sum);
        }
        catch (Exception ex) {
        }

        //	Return the checksum
        return checksum;
    }
}