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 */ 031public class LineBreaker 032{ 033 /** The default maximal line length. */ 034 public static final int DEFAULT_MAX_LINE_LENGTH = 78; 035 036 /** The system dependent EOL. */ 037 private static final String EOL = System.getProperty( "line.separator" ); 038 039 /** The destination writer. */ 040 private Writer destination; 041 042 /** The writer to use. */ 043 private BufferedWriter writer; 044 045 /** The maximal line length. */ 046 private int maxLineLength; 047 048 /** The current line length. */ 049 private int lineLength = 0; 050 051 /** The string buffer to store the current text. */ 052 private StringBuilder word = new StringBuilder( 1024 ); 053 054 /** 055 * Constructs a new LineBreaker with DEFAULT_MAX_LINE_LENGTH. 056 * 057 * @param out The writer to use. 058 */ 059 public LineBreaker( Writer out ) 060 { 061 this( out, DEFAULT_MAX_LINE_LENGTH ); 062 } 063 064 /** 065 * Constructs a new LineBreaker with the given max line length. 066 * 067 * @param out The writer to use. 068 * @param max The maximal line length. 069 */ 070 public LineBreaker( Writer out, int max ) 071 { 072 if ( max <= 0 ) 073 { 074 throw new IllegalArgumentException( "maxLineLength <= 0" ); 075 } 076 077 destination = out; 078 this.maxLineLength = max; 079 writer = new BufferedWriter( out ); 080 } 081 082 /** 083 * Returns the current destination writer. 084 * 085 * @return The destination. 086 */ 087 public Writer getDestination() 088 { 089 return destination; 090 } 091 092 /** 093 * Writes the given text to the writer. White space is not preserved. 094 * 095 * @param text The text to write. 096 * @throws java.io.IOException if there's a problem writing the text. 097 */ 098 public void write( String text ) 099 throws IOException 100 { 101 write( text, /*preserveSpace*/false ); 102 } 103 104 /** 105 * Writes the given text to the writer. 106 * 107 * @param text The text to write. 108 * @param preserveSpace True to preserve white space. 109 */ 110 public void write( String text, boolean preserveSpace ) 111 { 112 int length = text.length(); 113 114 try 115 { 116 for ( int i = 0; i < length; ++i ) 117 { 118 char c = text.charAt( i ); 119 120 switch ( c ) 121 { 122 case ' ': 123 if ( preserveSpace ) 124 { 125 word.append( c ); 126 } 127 else 128 { 129 writeWord(); 130 } 131 break; 132 133 case '\r': 134 // if \r\n (windows) then just pass along \n 135 if ( i + 1 < length && text.charAt( i + 1 ) == '\n' ) 136 { 137 break; 138 } 139 140 case '\n': 141 writeWord(); 142 writer.write( EOL ); 143 lineLength = 0; 144 break; 145 146 default: 147 word.append( c ); 148 } 149 150 } 151 } 152 catch ( Exception e ) 153 { 154 // TODO: log 155 } 156 } 157 158 /** 159 * Write out the current StringBuilder and flush the writer. 160 * Any IOException will be swallowed. 161 */ 162 public void flush() 163 { 164 try 165 { 166 writeWord(); 167 writer.flush(); 168 } 169 catch ( IOException e ) 170 { 171 // TODO: log 172 } 173 } 174 175 /** 176 * Writes the current StringBuilder to the writer. 177 * 178 * @throws IOException if an exception occurs during writing. 179 */ 180 private void writeWord() 181 throws IOException 182 { 183 int length = word.length(); 184 if ( length > 0 ) 185 { 186 if ( lineLength > 0 ) 187 { 188 if ( lineLength + 1 + length > maxLineLength ) 189 { 190 writer.write( EOL ); 191 lineLength = 0; 192 } 193 else 194 { 195 writer.write( ' ' ); 196 ++lineLength; 197 } 198 } 199 200 writer.write( word.toString() ); 201 word.setLength( 0 ); 202 203 lineLength += length; 204 } 205 } 206 207 /** 208 * Close the writer. 209 */ 210 public void close() 211 { 212 IOUtil.close( writer ); 213 } 214}