001    package org.apache.commons.openpgp;
002    
003    /*
004     * Licensed to the Apache Software Foundation (ASF) under one or more
005     * contributor license agreements.  See the NOTICE file distributed with
006     * this work for additional information regarding copyright ownership.
007     * The ASF licenses this file to You under the Apache License, Version 2.0
008     * (the "License"); you may not use this file except in compliance with
009     * the License.  You may obtain a copy of the License at
010     *
011     *      http://www.apache.org/licenses/LICENSE-2.0
012     *
013     * Unless required by applicable law or agreed to in writing, software
014     * distributed under the License is distributed on an "AS IS" BASIS,
015     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
016     * See the License for the specific language governing permissions and
017     * limitations under the License.
018     */
019    
020    import java.io.IOException;
021    
022    /**
023     * An interface for updating an OpenPGP signature on the fly with streaming data.
024     *
025     * @author <a href="mailto:brett@apache.org">Brett Porter</a>
026     */
027    public interface OpenPgpStreamingSigner
028    {
029        String ROLE = OpenPgpStreamingSigner.class.getName();
030    
031        /**
032         * Update the signature with the next block from the data buffer.
033         *
034         * @param buf the buffer
035         * @throws OpenPgpException if the buffer is not valid for updating the signature
036         */
037        void update( byte[] buf )
038            throws OpenPgpException;
039    
040        /**
041         * Update the signature with the next block from the data buffer.
042         *
043         * @param buf    the buffer
044         * @param offset offset within the buffer to start from
045         * @param length number of bytes in the buffer to read from
046         * @throws OpenPgpException if the buffer is not valid for updating the signature
047         */
048        void update( byte[] buf, int offset, int length )
049            throws OpenPgpException;
050    
051        /**
052         * Finish creating the signature.
053         *
054         * @return the completed signature
055         * @throws OpenPgpException if the signature is not in a consistent or complete state
056         */
057        byte[] finish()
058            throws OpenPgpException, IOException;
059    }