001package org.apache.maven.doxia.util; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import org.codehaus.plexus.util.IOUtil; 023 024import java.io.BufferedWriter; 025import java.io.IOException; 026import java.io.Writer; 027 028/** 029 * Allows to specify the line-length of an output writer. 030 * 031 * @version $Id$ 032 */ 033public class LineBreaker 034{ 035 /** The default maximal line length. */ 036 public static final int DEFAULT_MAX_LINE_LENGTH = 78; 037 038 /** The system dependent EOL. */ 039 private static final String EOL = System.getProperty( "line.separator" ); 040 041 /** The destination writer. */ 042 private Writer destination; 043 044 /** The writer to use. */ 045 private BufferedWriter writer; 046 047 /** The maximal line length. */ 048 private int maxLineLength; 049 050 /** The current line length. */ 051 private int lineLength = 0; 052 053 /** The string buffer to store the current text. */ 054 private StringBuilder word = new StringBuilder( 1024 ); 055 056 /** 057 * Constructs a new LineBreaker with DEFAULT_MAX_LINE_LENGTH. 058 * 059 * @param out The writer to use. 060 */ 061 public LineBreaker( Writer out ) 062 { 063 this( out, DEFAULT_MAX_LINE_LENGTH ); 064 } 065 066 /** 067 * Constructs a new LineBreaker with the given max line length. 068 * 069 * @param out The writer to use. 070 * @param max The maximal line length. 071 */ 072 public LineBreaker( Writer out, int max ) 073 { 074 if ( max <= 0 ) 075 { 076 throw new IllegalArgumentException( "maxLineLength <= 0" ); 077 } 078 079 destination = out; 080 this.maxLineLength = max; 081 writer = new BufferedWriter( out ); 082 } 083 084 /** 085 * Returns the current destination writer. 086 * 087 * @return The destination. 088 */ 089 public Writer getDestination() 090 { 091 return destination; 092 } 093 094 /** 095 * Writes the given text to the writer. White space is not preserved. 096 * 097 * @param text The text to write. 098 * @throws java.io.IOException if there's a problem writing the text. 099 */ 100 public void write( String text ) 101 throws IOException 102 { 103 write( text, /*preserveSpace*/false ); 104 } 105 106 /** 107 * Writes the given text to the writer. 108 * 109 * @param text The text to write. 110 * @param preserveSpace True to preserve white space. 111 */ 112 public void write( String text, boolean preserveSpace ) 113 { 114 int length = text.length(); 115 116 try 117 { 118 for ( int i = 0; i < length; ++i ) 119 { 120 char c = text.charAt( i ); 121 122 switch ( c ) 123 { 124 case ' ': 125 if ( preserveSpace ) 126 { 127 word.append( c ); 128 } 129 else 130 { 131 writeWord(); 132 } 133 break; 134 135 case '\r': 136 // if \r\n (windows) then just pass along \n 137 if ( i + 1 < length && text.charAt( i + 1 ) == '\n' ) 138 { 139 break; 140 } 141 142 case '\n': 143 writeWord(); 144 writer.write( EOL ); 145 lineLength = 0; 146 break; 147 148 default: 149 word.append( c ); 150 } 151 152 } 153 } 154 catch ( Exception e ) 155 { 156 // TODO: log 157 } 158 } 159 160 /** 161 * Write out the current StringBuilder and flush the writer. 162 * Any IOException will be swallowed. 163 */ 164 public void flush() 165 { 166 try 167 { 168 writeWord(); 169 writer.flush(); 170 } 171 catch ( IOException e ) 172 { 173 // TODO: log 174 } 175 } 176 177 /** 178 * Writes the current StringBuilder to the writer. 179 * 180 * @throws IOException if an exception occurs during writing. 181 */ 182 private void writeWord() 183 throws IOException 184 { 185 int length = word.length(); 186 if ( length > 0 ) 187 { 188 if ( lineLength > 0 ) 189 { 190 if ( lineLength + 1 + length > maxLineLength ) 191 { 192 writer.write( EOL ); 193 lineLength = 0; 194 } 195 else 196 { 197 writer.write( ' ' ); 198 ++lineLength; 199 } 200 } 201 202 writer.write( word.toString() ); 203 word.setLength( 0 ); 204 205 lineLength += length; 206 } 207 } 208 209 /** 210 * Close the writer. 211 */ 212 public void close() 213 { 214 IOUtil.close( writer ); 215 } 216}