net.geertvos.gossip.core.Md5HashProvider.java Source code

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Here is the source code for net.geertvos.gossip.core.Md5HashProvider.java

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/**
This file is part of the Java Gossip Cluster Framework.
    
The Java Gossip Framework is free software: you can redistribute it and/or modify
it under the terms of the Lesser GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
The Java Gossip Framework is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this framework.  If not, see <http://www.gnu.org/licenses/>.
 */
package net.geertvos.gossip.core;

import java.nio.charset.Charset;
import java.security.MessageDigest;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;

import net.geertvos.gossip.api.cluster.ClusterHashProvider;
import net.geertvos.gossip.api.cluster.ClusterMember;

import org.apache.commons.codec.Charsets;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.digest.DigestUtils;

/**
 * @author Geert Vos
 */
public class Md5HashProvider implements ClusterHashProvider<GossipClusterMember> {

    private final ClusterMemberComperator comperator = new ClusterMemberComperator();
    private final MessageDigest digester = DigestUtils.getMd5Digest();
    private final Charset charset = Charsets.UTF_8;

    @Override
    public String hashCluster(Collection<GossipClusterMember> members) {
        List<GossipClusterMember> sortedMembers = new ArrayList<GossipClusterMember>(members);
        Collections.sort(sortedMembers, comperator);

        StringBuilder stringBuilder = new StringBuilder();
        for (ClusterMember member : sortedMembers) {
            stringBuilder.append(member.getId() + "|");
        }

        byte[] bytes = stringBuilder.toString().getBytes(charset);
        byte[] digest = digester.digest(bytes);
        byte[] encoded = Base64.encodeBase64(digest);
        return new String(encoded, charset);
    }

}