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    1   /*
    2    *  Licensed to the Apache Software Foundation (ASF) under one
    3    *  or more contributor license agreements.  See the NOTICE file
    4    *  distributed with this work for additional information
    5    *  regarding copyright ownership.  The ASF licenses this file
    6    *  to you under the Apache License, Version 2.0 (the
    7    *  "License"); you may not use this file except in compliance
    8    *  with the License.  You may obtain a copy of the License at
    9    *
    10   *    http://www.apache.org/licenses/LICENSE-2.0
    11   *
    12   *  Unless required by applicable law or agreed to in writing,
    13   *  software distributed under the License is distributed on an
    14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    15   *  KIND, either express or implied.  See the License for the
    16   *  specific language governing permissions and limitations
    17   *  under the License.
    18   *
    19   */
    20  package org.apache.mina.codec.textline;
    21
    22  import java.nio.ByteBuffer;
    23  import java.nio.CharBuffer;
    24  import java.nio.charset.CharacterCodingException;
    25  import java.nio.charset.Charset;
    26  import java.nio.charset.CharsetEncoder;
    27
    28  import org.apache.mina.codec.ProtocolEncoder;
    29  import org.apache.mina.codec.StatelessProtocolEncoder;
    30
    31  /**
    32   * A {@link ProtocolEncoder} which encodes a string into a text line
    33   * which ends with the delimiter.
    34   *
    35   * @author <a href="http://mina.apache.org">Apache MINA Project</a>
    36   */
    37  public class TextLineEncoder implements StatelessProtocolEncoder<String, ByteBuffer> {
    38      private final CharsetEncoder charsetEncoder;
    39
    40      private final LineDelimiter delimiter;
    41
    42      private int maxLineLength = Integer.MAX_VALUE;
    43
    44      /**
    45       * Creates a new instance with the current default {@link Charset}
    46       * and {@link LineDelimiter#UNIX} delimiter.
    47       */
    48      public TextLineEncoder() {
    49          this(Charset.defaultCharset(), LineDelimiter.UNIX);
    50      }
    51
    52      /**
    53       * Creates a new instance with the current default {@link Charset}
    54       * and the specified <tt>delimiter</tt>.
    55       */
    56      public TextLineEncoder(String delimiter) {
    57          this(new LineDelimiter(delimiter));
    58      }
    59
    60      /**
    61       * Creates a new instance with the current default {@link Charset}
    62       * and the specified <tt>delimiter</tt>.
    63       */
    64      public TextLineEncoder(LineDelimiter delimiter) {
    65          this(Charset.defaultCharset(), delimiter);
    66      }
    67
    68      /**
    69       * Creates a new instance with the spcified <tt>charset</tt>
    70       * and {@link LineDelimiter#UNIX} delimiter.
    71       */
    72      public TextLineEncoder(Charset charset) {
    73          this(charset, LineDelimiter.UNIX);
    74      }
    75
    76      /**
    77       * Creates a new instance with the spcified <tt>charset</tt>
    78       * and the specified <tt>delimiter</tt>.
    79       */
    80      public TextLineEncoder(Charset charset, String delimiter) {
    81          this(charset, new LineDelimiter(delimiter));
    82      }
    83
    84      /**
    85       * Creates a new instance with the spcified <tt>charset</tt>
    86       * and the specified <tt>delimiter</tt>.
    87       */
    88      public TextLineEncoder(Charset charset, LineDelimiter delimiter) {
    89          if (charset == null) {
    90              throw new IllegalArgumentException("charset");
    91          }
    92          if (delimiter == null) {
    93              throw new IllegalArgumentException("delimiter");
    94          }
    95          if (LineDelimiter.AUTO.equals(delimiter)) {
    96              throw new IllegalArgumentException("AUTO delimiter is not allowed for encoder.");
    97          }
    98
    99          this.charsetEncoder = charset.newEncoder();
    100         this.delimiter = delimiter;
    101     }
    102
    103     /**
    104      * Returns the allowed maximum size of the encoded line.
    105      * If the size of the encoded line exceeds this value, the encoder
    106      * will throw a {@link IllegalArgumentException}.  The default value
    107      * is {@link Integer#MAX_VALUE}.
    108      */
    109     public int getMaxLineLength() {
    110         return maxLineLength;
    111     }
    112
    113     /**
    114      * Sets the allowed maximum size of the encoded line.
    115      * If the size of the encoded line exceeds this value, the encoder
    116      * will throw a {@link IllegalArgumentException}.  The default value
    117      * is {@link Integer#MAX_VALUE}.
    118      */
    119     public void setMaxLineLength(int maxLineLength) {
    120         if (maxLineLength <= 0) {
    121             throw new IllegalArgumentException("maxLineLength: " + maxLineLength);
    122         }
    123
    124         this.maxLineLength = maxLineLength;
    125     }
    126
    127     @Override
    128     public Void createEncoderState() {
    129         return null;
    130     }
    131
    132     @Override
    133     public ByteBuffer encode(String message, Void context) {
    134         try {
    135             String value = (message == null ? "" : message);
    136
    137             if (value.length() > maxLineLength) {
    138                 throw new IllegalArgumentException("Line length: " + message.length());
    139             }
    140             return charsetEncoder.encode(CharBuffer.wrap(value + delimiter.getValue()));
    141         } catch (CharacterCodingException e) {
    142             throw new RuntimeException(e);
    143         }
    144     }
    145
    146 }