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 */
020package org.apache.mina.filter.codec.textline;
021
022import java.io.ByteArrayOutputStream;
023import java.io.PrintWriter;
024
025/**
026 * A delimiter which is appended to the end of a text line, such as
027 * <tt>CR/LF</tt>. This class defines default delimiters for various
028 * OS :
029 * <ul>
030 * <li><b>Unix/Linux</b> : LineDelimiter.UNIX ("\n")</li>
031 * <li><b>Windows</b> : LineDelimiter.WINDOWS ("\r\n")</li>
032 * <li><b>MAC</b> : LineDelimiter.MAC ("\r")</li>
033 * </ul>
034 *
035 * @author <a href="http://mina.apache.org">Apache MINA Project</a>
036 */
037public class LineDelimiter {
038    /** the line delimiter constant of the current O/S. */
039    public static final LineDelimiter DEFAULT;
040
041    /** Compute the default delimiter on he current OS */
042    static {
043        ByteArrayOutputStream bout = new ByteArrayOutputStream();
044        PrintWriter out = new PrintWriter(bout, true);
045        out.println();
046        DEFAULT = new LineDelimiter(new String(bout.toByteArray()));
047    }
048
049    /**
050     * A special line delimiter which is used for auto-detection of
051     * EOL in {@link TextLineDecoder}.  If this delimiter is used,
052     * {@link TextLineDecoder} will consider both  <tt>'\r'</tt> and
053     * <tt>'\n'</tt> as a delimiter.
054     */
055    public static final LineDelimiter AUTO = new LineDelimiter("");
056
057    /**
058     * The CRLF line delimiter constant (<tt>"\r\n"</tt>)
059     */
060    public static final LineDelimiter CRLF = new LineDelimiter("\r\n");
061
062    /**
063     * The line delimiter constant of UNIX (<tt>"\n"</tt>)
064     */
065    public static final LineDelimiter UNIX = new LineDelimiter("\n");
066
067    /**
068     * The line delimiter constant of MS Windows/DOS (<tt>"\r\n"</tt>)
069     */
070    public static final LineDelimiter WINDOWS = CRLF;
071
072    /**
073     * The line delimiter constant of Mac OS (<tt>"\r"</tt>)
074     */
075    public static final LineDelimiter MAC = new LineDelimiter("\r");
076
077    /**
078     * The line delimiter constant for NUL-terminated text protocols
079     * such as Flash XML socket (<tt>"\0"</tt>)
080     */
081    public static final LineDelimiter NUL = new LineDelimiter("\0");
082
083    /** Stores the selected Line delimiter */
084    private final String value;
085
086    /**
087     * Creates a new line delimiter with the specified <tt>value</tt>.
088     * 
089     * @param value The new Line Delimiter
090     */
091    public LineDelimiter(String value) {
092        if (value == null) {
093            throw new IllegalArgumentException("delimiter");
094        }
095
096        this.value = value;
097    }
098
099    /**
100     * @return the delimiter string.
101     */
102    public String getValue() {
103        return value;
104    }
105
106    /**
107     * {@inheritDoc}
108     */
109    @Override
110    public int hashCode() {
111        return value.hashCode();
112    }
113
114    /**
115     * {@inheritDoc}
116     */
117    @Override
118    public boolean equals(Object o) {
119        if (this == o) {
120            return true;
121        }
122
123        if (!(o instanceof LineDelimiter)) {
124            return false;
125        }
126
127        LineDelimiter that = (LineDelimiter) o;
128
129        return this.value.equals(that.value);
130    }
131
132    /**
133     * {@inheritDoc}
134     */
135    @Override
136    public String toString() {
137        if (value.length() == 0) {
138            return "delimiter: auto";
139        } else {
140            StringBuilder buf = new StringBuilder();
141            buf.append("delimiter:");
142
143            for (int i = 0; i < value.length(); i++) {
144                buf.append(" 0x");
145                buf.append(Integer.toHexString(value.charAt(i)));
146            }
147
148            return buf.toString();
149        }
150    }
151}