org.apache.maven.plugin.install.DualDigester.java Source code

Introduction

Here is the source code for org.apache.maven.plugin.install.DualDigester.java

Source

package org.apache.maven.plugin.install;

/*
 * 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.
 */

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.codec.binary.Hex;
import org.apache.maven.plugin.MojoExecutionException;
import org.codehaus.plexus.util.IOUtil;

/**
 * Calculates md5 and sha1 digest.
 * <p/>
 * Todo: Consider using a thread to calculate one of the digests when the files are large; it's fairly slow !
 *
 * @author Kristian Rosenvold
 */
public class DualDigester {
    private final MessageDigest md5 = getDigester("MD5");

    private final MessageDigest sh1 = getDigester("SHA-1");

    private static final int bufsize = 65536 * 2;

    private final byte[] buffer = new byte[bufsize];

    static MessageDigest getDigester(String algorithm) {
        try {
            return MessageDigest.getInstance(algorithm);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("Unable to initialize digest " + algorithm + " : " + e.getMessage());
        }
    }

    public void calculate(File file) throws MojoExecutionException {
        FileInputStream fis = null;
        BufferedInputStream bis = null;

        try {
            fis = new FileInputStream(file);
            calculate(fis);
        } catch (IOException e) {
            throw new MojoExecutionException("Failed to calculate digest checksum for " + file, e);
        } finally {
            IOUtil.close(bis);
            IOUtil.close(fis);
        }
    }

    void calculate(InputStream stream) throws IOException {
        md5.reset();
        sh1.reset();
        update(stream);
    }

    public String getMd5() {
        return Hex.encodeHexString(md5.digest());
    }

    public String getSha1() {
        return Hex.encodeHexString(sh1.digest());
    }

    private void update(InputStream is) throws IOException {
        int size = is.read(buffer, 0, bufsize);
        while (size >= 0) {
            md5.update(buffer, 0, size);
            sh1.update(buffer, 0, size);
            size = is.read(buffer, 0, bufsize);
        }
    }
}