001package org.eclipse.aether.internal.impl.checksum;
002
003/*
004 * Licensed to the Apache Software Foundation (ASF) under one
005 * or more contributor license agreements.  See the NOTICE file
006 * distributed with this work for additional information
007 * regarding copyright ownership.  The ASF licenses this file
008 * to you under the Apache License, Version 2.0 (the
009 * "License"); you may not use this file except in compliance
010 * with the License.  You may obtain a copy of the License at
011 *
012 *  http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing,
015 * software distributed under the License is distributed on an
016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017 * KIND, either express or implied.  See the License for the
018 * specific language governing permissions and limitations
019 * under the License.
020 */
021
022import org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithm;
023import org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithmFactory;
024import org.eclipse.aether.spi.connector.checksum.ChecksumAlgorithmFactorySupport;
025import org.eclipse.aether.util.ChecksumUtils;
026
027import java.nio.ByteBuffer;
028import java.security.MessageDigest;
029import java.security.NoSuchAlgorithmException;
030
031/**
032 * Support class to implement {@link ChecksumAlgorithmFactory} based on Java {@link MessageDigest}.
033 *
034 * @since 1.8.0
035 */
036public abstract class MessageDigestChecksumAlgorithmFactorySupport
037        extends ChecksumAlgorithmFactorySupport
038{
039    public MessageDigestChecksumAlgorithmFactorySupport( String name, String extension )
040    {
041        super( name, extension );
042    }
043
044    @Override
045    public ChecksumAlgorithm getAlgorithm()
046    {
047        try
048        {
049            MessageDigest messageDigest = MessageDigest.getInstance( getName() );
050            return new ChecksumAlgorithm()
051            {
052                @Override
053                public void update( final ByteBuffer input )
054                {
055                    messageDigest.update( input );
056                }
057
058                @Override
059                public String checksum()
060                {
061                    return ChecksumUtils.toHexString( messageDigest.digest() );
062                }
063            };
064        }
065        catch ( NoSuchAlgorithmException e )
066        {
067            throw new IllegalStateException(
068                    "MessageDigest algorithm " + getName() + " not supported, but is required by resolver.", e );
069        }
070    }
071}