org.apache.archiva.checksum.Checksum.java Source code

Introduction

Here is the source code for org.apache.archiva.checksum.Checksum.java

Source

package org.apache.archiva.checksum;

/*
 * 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 org.apache.commons.io.IOUtils;
import org.apache.commons.io.output.NullOutputStream;

import java.io.IOException;
import java.io.InputStream;
import java.security.DigestInputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.List;

/**
 * Checksum - simple checksum hashing routines.
 */
public class Checksum {
    private static final int BUFFER_SIZE = 32768;

    public static void update(List<Checksum> checksums, InputStream stream) throws IOException {
        byte[] buffer = new byte[BUFFER_SIZE];
        int size = stream.read(buffer, 0, BUFFER_SIZE);
        while (size >= 0) {
            for (Checksum checksum : checksums) {
                checksum.update(buffer, 0, size);
            }
            size = stream.read(buffer, 0, BUFFER_SIZE);
        }
    }

    private final MessageDigest md;

    private ChecksumAlgorithm checksumAlgorithm;

    public Checksum(ChecksumAlgorithm checksumAlgorithm) {
        this.checksumAlgorithm = checksumAlgorithm;
        try {
            md = MessageDigest.getInstance(checksumAlgorithm.getAlgorithm());
        } catch (NoSuchAlgorithmException e) {
            // Not really possible, but here none-the-less
            throw new IllegalStateException("Unable to initialize MessageDigest algorithm "
                    + checksumAlgorithm.getAlgorithm() + " : " + e.getMessage(), e);
        }
    }

    public String getChecksum() {
        return Hex.encode(md.digest());
    }

    public ChecksumAlgorithm getAlgorithm() {
        return this.checksumAlgorithm;
    }

    public void reset() {
        md.reset();
    }

    public Checksum update(byte[] buffer, int offset, int size) {
        md.update(buffer, 0, size);
        return this;
    }

    public Checksum update(InputStream stream) throws IOException {
        try (DigestInputStream dig = new DigestInputStream(stream, md)) {
            IOUtils.copy(dig, new NullOutputStream());
        }
        return this;
    }
}