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package org.apidesign.impl.security.spi;

import java.nio.ByteBuffer;

import org.apidesign.spi.security.Digestor;

/**

 *

 * @author jarda

 */

public abstract class DigestorAccessor {

    private static DigestorAccessor INSTANCE;

    protected DigestorAccessor() {

        assert INSTANCE == null;

        INSTANCE = this;

    }

    public static DigestorAccessor getDefault() {

        try {

            Class.forName(Digestor.class.getName(), true, DigestorAccessor.class.getClassLoader());

            return INSTANCE;

        } catch (ClassNotFoundException ex) {

            throw new IllegalStateException(ex);

        }

    }

    protected abstract <Data> byte[] digest(Digestor<Data> dig, Data data);

    protected abstract <Data> Data create(Digestor<Data> dig, String algorithm); 

    protected abstract <Data> void update(Digestor<Data> dig, Data data, ByteBuffer input);

}