org.apache.oodt.product.handlers.ofsn.MD5GetHandler.java Source code

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Here is the source code for org.apache.oodt.product.handlers.ofsn.MD5GetHandler.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF 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 org.apache.oodt.product.handlers.ofsn;

//JDK imports

import org.apache.commons.codec.binary.Hex;
import org.apache.commons.io.FileUtils;
import org.apache.oodt.product.ProductException;

import java.io.ByteArrayInputStream;
import java.io.File;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;

//APACHE imports
//OODT imports

/**
 * 
 * A {@link OFSNGetHandler} to perform an MD5 for a file on the server side.
 * 
 * @author mattmann
 * @version $Revision$
 * 
 */
public class MD5GetHandler implements OFSNGetHandler {

    private MessageDigest md = null;
    private static Logger LOG = Logger.getLogger(MD5GetHandler.class.getName());

    public MD5GetHandler() throws InstantiationException {
        try {
            this.md = MessageDigest.getInstance("MD5");
        } catch (NoSuchAlgorithmException e) {
            LOG.log(Level.SEVERE, e.getMessage());
            throw new InstantiationException(e.getMessage());
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.apache.oodt.product.handlers.ofsn.OFSNListHandler#configure(java.
     * util.Properties)
     */
    public void configure(Properties conf) {
        // TODO Auto-generated method stub

    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.apache.oodt.product.handlers.ofsn.OFSNGetHandler#retrieveChunk(java
     * .lang.String, long, int)
     */
    public byte[] retrieveChunk(String filepath, long offset, int length) throws ProductException {
        try {
            String hash = this.hashData(FileUtils.readFileToByteArray(new File(filepath)));
            byte[] retBytes = new byte[length];
            byte[] hashBytes = hash.getBytes();
            ByteArrayInputStream is = new ByteArrayInputStream(hashBytes);
            is.skip(offset);
            is.read(retBytes, 0, length);
            return retBytes;
        } catch (IOException e) {
            LOG.log(Level.SEVERE, e.getMessage());
            throw new ProductException(
                    "Error reading bytes from file: [" + filepath + "] MD5: Message: " + e.getMessage());
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see
     * org.apache.oodt.product.handlers.ofsn.OFSNGetHandler#sizeOf(java.lang
     * .String)
     */
    public long sizeOf(String filepath) {
        try {
            String hash = this.hashData(FileUtils.readFileToByteArray(new File(filepath)));
            return hash.getBytes().length;
        } catch (IOException e) {
            LOG.log(Level.SEVERE, e.getMessage());
            return -1;
        }
    }

    /**
     * Use this method ot generate a test MD5 of a provide {@link File} specified
     * in args[0].
     * 
     * @param args
     *          Only need to specify 1 arg, the full path to the {@link File} to
     *          MD5.
     * @throws Exception
     *           If any error occurs.
     */
    public static void main(String[] args) throws Exception {
        if (args.length != 1) {
            System.err.println("MD5GetHandler <file>");
            System.exit(1);
        }

        String filepath = args[0];
        String hashString = new MD5GetHandler().hashData(FileUtils.readFileToByteArray(new File(filepath)));
        System.out.println(hashString);
    }

    private String hashData(byte[] dataToHash) {
        this.md.update(dataToHash, 0, dataToHash.length);
        byte[] hash = this.md.digest();
        return new String(Hex.encodeHex(hash));
    }

}