001/*
002 * Sonar, open source software quality management tool.
003 * Copyright (C) 2008-2012 SonarSource
004 * mailto:contact AT sonarsource DOT com
005 *
006 * Sonar is free software; you can redistribute it and/or
007 * modify it under the terms of the GNU Lesser General Public
008 * License as published by the Free Software Foundation; either
009 * version 3 of the License, or (at your option) any later version.
010 *
011 * Sonar is distributed in the hope that it will be useful,
012 * but WITHOUT ANY WARRANTY; without even the implied warranty of
013 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014 * Lesser General Public License for more details.
015 *
016 * You should have received a copy of the GNU Lesser General Public
017 * License along with Sonar; if not, write to the Free Software
018 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02
019 */
020package org.sonar.channel;
021
022import java.io.IOException;
023import java.io.Reader;
024
025/**
026 * This class can be extended to provide filtering capabilities for the CodeReader class. <br>
027 * The purpose is to filter the character flow before the CodeReader class passes it to the different channels. It is possible to give
028 * several filters to a CodeReader: they will be called one after another, following the declaration order in the CodeReader constructor, to
029 * sequentially filter the character flow.
030 * 
031 * @see CodeReader
032 * @see CodeBufferTest#testCodeReaderFilter()
033 * @see CodeBufferTest#testSeveralCodeReaderFilter()
034 * 
035 */
036public abstract class CodeReaderFilter<OUTPUT> {
037
038  private Reader reader;
039
040  private OUTPUT output;
041
042  private CodeReaderConfiguration configuration;
043
044  public CodeReaderFilter() {
045  }
046
047  public CodeReaderFilter(OUTPUT output) {
048    this.output = output;
049  }
050
051  /**
052   * Returns the reader from which this class reads the character stream.
053   * 
054   * @return the reader
055   */
056  public Reader getReader() {
057    return reader;
058  }
059
060  /**
061   * Sets the reader from which this class will read the character stream.
062   * 
063   * @param reader
064   *          the reader
065   */
066  public void setReader(Reader reader) {
067    this.reader = reader;
068  }
069
070  /**
071   * Returns the output object.
072   * 
073   * @return the output
074   */
075  public OUTPUT getOutput() {
076    return output;
077  }
078
079  /**
080   * Sets the output object
081   * 
082   * @param output
083   *          the output to set
084   */
085  public void setOutput(OUTPUT output) {
086    this.output = output;
087  }
088
089  /**
090   * Returns the configuration used for the CodeReader
091   * 
092   * @return the configuration
093   */
094  public CodeReaderConfiguration getConfiguration() {
095    return configuration;
096  }
097
098  /**
099   * Sets the configuration that must be used by the CodeReader
100   * 
101   * @param configuration
102   *          the configuration to set
103   */
104  public void setConfiguration(CodeReaderConfiguration configuration) {
105    this.configuration = configuration;
106  }
107
108  /**
109   * This method implements the filtering logic, that is:
110   * <ul>
111   * <li>
112   * get the characters from the reader,</li>
113   * <li>
114   * filter the character flow (and grab more characters from the reader if the filtering removes some),</li>
115   * <li>
116   * and fill the given buffer to its full capacity with the filtered data.</li>
117   * </ul>
118   * 
119   * @param filteredBuffer
120   *          the output buffer that must contain the filtered data
121   * @param offset
122   *          the offset to start reading from the reader
123   * @param length
124   *          the number of characters to read from the reader
125   * @return The number of characters read, or -1 if the end of the stream has been reached
126   * @throws IOException
127   *           If an I/O error occurs
128   */
129  public abstract int read(char[] filteredBuffer, int offset, int length) throws IOException;
130
131}