org.archive.wayback.util.FileDownloader.java Source code

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Here is the source code for org.archive.wayback.util.FileDownloader.java

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/*
 *  This file is part of the Wayback archival access software
 *   (http://archive-access.sourceforge.net/projects/wayback/).
 *
 *  Licensed to the Internet Archive (IA) by one or more individual 
 *  contributors. 
 *
 *  The IA 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.archive.wayback.util;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URL;
import java.security.DigestOutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.zip.GZIPInputStream;

import org.apache.commons.codec.binary.Hex;

/**
 *
 *
 * @author brad
 * @version $Date$, $Revision$
 */
public class FileDownloader {
    private boolean digest = false;
    private String lastDigest;

    /**
     * @return Returns the lastDigest.
     */
    public String getLastDigest() {
        return lastDigest;
    }

    /**
     * @param digest The digest to set.
     */
    public void setDigest(boolean digest) {
        this.digest = digest;
    }

    private void download(URL url, File target, boolean gz) throws IOException, NoSuchAlgorithmException {

        OutputStream os;
        MessageDigest digester = null;
        InputStream is;
        if (gz) {
            is = new GZIPInputStream(url.openStream());
        } else {
            is = url.openStream();
        }

        FileOutputStream fos = new FileOutputStream(target);
        BufferedOutputStream bos = new BufferedOutputStream(fos);
        if (digest) {
            digester = MessageDigest.getInstance("MD5");
            os = new DigestOutputStream(bos, digester);
        } else {
            os = bos;
        }
        int BUF_SIZE = 4096;
        byte[] buffer = new byte[BUF_SIZE];
        for (int r = -1; (r = is.read(buffer, 0, BUF_SIZE)) != -1;) {
            os.write(buffer, 0, r);
        }
        is.close();
        os.flush();
        os.close();
        if (digest) {
            this.lastDigest = new String(Hex.encodeHex(digester.digest()));
        }
    }

    /**
     * @param url URL to download
     * @param target local File where uncompressed content of URL is stored
     * @throws IOException 
     * @throws NoSuchAlgorithmException 
     */
    public void download(URL url, File target) throws IOException, NoSuchAlgorithmException {
        download(url, target, false);
    }

    /**
     * @param url URL to download
     * @param target local File where uncompressed content of URL is stored
     * @throws IOException 
     * @throws NoSuchAlgorithmException 
     */
    public void downloadGZ(URL url, File target) throws IOException, NoSuchAlgorithmException {
        download(url, target, true);
    }
}