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 */ 019package org.apache.maven.doxia.util; 020 021import java.io.BufferedWriter; 022import java.io.IOException; 023import java.io.Writer; 024 025/** 026 * Allows to specify the line-length of an output writer. 027 */ 028public class LineBreaker { 029 /** The default maximal line length. */ 030 public static final int DEFAULT_MAX_LINE_LENGTH = 78; 031 032 /** The system dependent EOL. */ 033 private static final String EOL = System.getProperty("line.separator"); 034 035 /** The destination writer. */ 036 private Writer destination; 037 038 /** The writer to use. */ 039 private BufferedWriter writer; 040 041 /** The maximal line length. */ 042 private int maxLineLength; 043 044 /** The current line length. */ 045 private int lineLength = 0; 046 047 /** The string buffer to store the current text. */ 048 private StringBuilder word = new StringBuilder(1024); 049 050 /** 051 * Constructs a new LineBreaker with DEFAULT_MAX_LINE_LENGTH. 052 * 053 * @param out The writer to use. 054 */ 055 public LineBreaker(Writer out) { 056 this(out, DEFAULT_MAX_LINE_LENGTH); 057 } 058 059 /** 060 * Constructs a new LineBreaker with the given max line length. 061 * 062 * @param out The writer to use. 063 * @param max The maximal line length. 064 */ 065 public LineBreaker(Writer out, int max) { 066 if (max <= 0) { 067 throw new IllegalArgumentException("max must be a positive integer"); 068 } 069 070 destination = out; 071 this.maxLineLength = max; 072 writer = new BufferedWriter(out); 073 } 074 075 /** 076 * Returns the current destination writer. 077 * 078 * @return The destination. 079 */ 080 public Writer getDestination() { 081 return destination; 082 } 083 084 /** 085 * Writes the given text to the writer. White space is not preserved. 086 * 087 * @param text The text to write. 088 * @throws java.io.IOException if there's a problem writing the text. 089 */ 090 public void write(String text) throws IOException { 091 write(text, /*preserveSpace*/ false); 092 } 093 094 /** 095 * Writes the given text to the writer. 096 * 097 * @param text The text to write. 098 * @param preserveSpace True to preserve white space. 099 */ 100 public void write(String text, boolean preserveSpace) { 101 int length = text.length(); 102 103 try { 104 for (int i = 0; i < length; ++i) { 105 char c = text.charAt(i); 106 107 switch (c) { 108 case ' ': 109 if (preserveSpace) { 110 word.append(c); 111 } else { 112 writeWord(); 113 } 114 break; 115 116 case '\r': 117 // if \r\n (windows) then just pass along \n 118 if (i + 1 < length && text.charAt(i + 1) == '\n') { 119 break; 120 } 121 122 case '\n': 123 writeWord(); 124 writer.write(EOL); 125 lineLength = 0; 126 break; 127 128 default: 129 word.append(c); 130 } 131 } 132 } catch (Exception e) { 133 // TODO: log 134 } 135 } 136 137 /** 138 * Write out the current StringBuilder and flush the writer. 139 * Any IOException will be swallowed. 140 */ 141 public void flush() { 142 try { 143 writeWord(); 144 writer.flush(); 145 } catch (IOException e) { 146 // TODO: log 147 } 148 } 149 150 /** 151 * Writes the current StringBuilder to the writer. 152 * 153 * @throws IOException if an exception occurs during writing. 154 */ 155 private void writeWord() throws IOException { 156 int length = word.length(); 157 if (length > 0) { 158 if (lineLength > 0) { 159 if (lineLength + 1 + length > maxLineLength) { 160 writer.write(EOL); 161 lineLength = 0; 162 } else { 163 writer.write(' '); 164 ++lineLength; 165 } 166 } 167 168 writer.write(word.toString()); 169 word.setLength(0); 170 171 lineLength += length; 172 } 173 } 174 175 /** 176 * Close the writer. 177 */ 178 public void close() { 179 if (writer == null) { 180 return; 181 } 182 183 try { 184 writer.close(); 185 } catch (IOException ex) { 186 // ignore 187 } 188 } 189}