001    /****************************************************************
002     * Licensed to the Apache Software Foundation (ASF) under one   *
003     * or more contributor license agreements.  See the NOTICE file *
004     * distributed with this work for additional information        *
005     * regarding copyright ownership.  The ASF licenses this file   *
006     * to you under the Apache License, Version 2.0 (the            *
007     * "License"); you may not use this file except in compliance   *
008     * with the License.  You may obtain a copy of the License at   *
009     *                                                              *
010     *   http://www.apache.org/licenses/LICENSE-2.0                 *
011     *                                                              *
012     * Unless required by applicable law or agreed to in writing,   *
013     * software distributed under the License is distributed on an  *
014     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
015     * KIND, either express or implied.  See the License for the    *
016     * specific language governing permissions and limitations      *
017     * under the License.                                           *
018     ****************************************************************/
019    
020    package org.apache.james.mime4j.io;
021    
022    import org.apache.james.mime4j.util.ByteArrayBuffer;
023    
024    import java.io.FilterInputStream;
025    import java.io.IOException;
026    import java.io.InputStream;
027    
028    /**
029     * Input stream capable of reading lines of text. 
030     */
031    public abstract class LineReaderInputStream extends FilterInputStream {
032    
033        protected LineReaderInputStream(InputStream in) {
034            super(in);
035        }
036    
037        /**
038         * Reads one line of text into the given {@link ByteArrayBuffer}.
039         *  
040         * @param dst Destination
041         * @return number of bytes copied or <code>-1</code> if the end of 
042         * the stream has been reached.
043         * 
044         * @throws IOException in case of an I/O error.
045         */
046        public abstract int readLine(final ByteArrayBuffer dst) throws IOException;
047        
048    }