1 package org.apache.maven.doxia.macro.snippet;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.io.BufferedReader;
23 import java.io.IOException;
24 import java.io.InputStreamReader;
25 import java.net.URL;
26 import java.util.ArrayList;
27 import java.util.List;
28 import java.util.Locale;
29
30 import org.codehaus.plexus.util.IOUtil;
31
32 /**
33 * Utility class for reading snippets.
34 *
35 * @version $Id: SnippetReader.java 1544338 2013-11-21 21:59:01Z michaelo $
36 */
37 public class SnippetReader
38 {
39 /** System-dependent EOL. */
40 private static final String EOL = System.getProperty( "line.separator" );
41
42 /** The source. */
43 private URL source;
44
45 /** The encoding of the source. */
46 private String encoding;
47
48 /**
49 * Constructor.
50 *
51 * @param src The source
52 * @param encoding The file encoding
53 */
54 public SnippetReader( URL src, String encoding )
55 {
56 this.source = src;
57 this.encoding = encoding;
58 }
59
60 /**
61 * Constructor.
62 *
63 * @param src The source
64 */
65 public SnippetReader( URL src )
66 {
67 this( src, null ) ;
68 }
69
70 /**
71 * Reads the snippet with given id.
72 *
73 * @param snippetId The id of the snippet.
74 * @return The snippet.
75 * @throws java.io.IOException if something goes wrong.
76 */
77 public StringBuffer readSnippet( String snippetId )
78 throws IOException
79 {
80 List<String> lines = readLines( snippetId );
81 int minIndent = minIndent( lines );
82 StringBuffer result = new StringBuffer();
83 for ( String line : lines )
84 {
85 result.append( line.substring( minIndent ) );
86 result.append( EOL );
87 }
88 return result;
89 }
90
91 /**
92 * Returns the minimal indent of all the lines in the given List.
93 *
94 * @param lines A List of lines.
95 * @return the minimal indent.
96 */
97 int minIndent( List<String> lines )
98 {
99 int minIndent = Integer.MAX_VALUE;
100 for ( String line : lines )
101 {
102 minIndent = Math.min( minIndent, indent( line ) );
103 }
104 return minIndent;
105 }
106
107 /**
108 * Returns the indent of the given line.
109 *
110 * @param line A line.
111 * @return the indent.
112 */
113 int indent( String line )
114 {
115 char[] chars = line.toCharArray();
116 int indent = 0;
117 for ( ; indent < chars.length; indent++ )
118 {
119 if ( chars[indent] != ' ' )
120 {
121 break;
122 }
123 }
124 return indent;
125 }
126
127 /**
128 * Reads the snippet and returns the lines in a List.
129 *
130 * @param snippetId The id of the snippet.
131 * @return A List of lines.
132 * @throws IOException if something goes wrong.
133 */
134 private List<String> readLines( String snippetId )
135 throws IOException
136 {
137 BufferedReader reader;
138 if ( encoding == null || "".equals( encoding ) )
139 {
140 reader = new BufferedReader( new InputStreamReader( source.openStream() ) );
141 }
142 else
143 {
144 reader = new BufferedReader( new InputStreamReader( source.openStream(), encoding ) );
145 }
146
147 List<String> lines = new ArrayList<String>();
148 try
149 {
150 boolean capture = false;
151 String line;
152 while ( ( line = reader.readLine() ) != null )
153 {
154 if ( snippetId == null || "".equals( snippetId.trim() ) )
155 {
156 lines.add( line );
157 }
158 else
159 {
160 if ( isStart( snippetId, line ) )
161 {
162 capture = true;
163 }
164 else if ( isEnd( snippetId, line ) )
165 {
166 break;
167 }
168 else if ( capture )
169 {
170 lines.add( line );
171 }
172 }
173 }
174 }
175 finally
176 {
177 IOUtil.close( reader );
178 }
179 return lines;
180 }
181
182 /**
183 * Determines if the given line is a start demarcator.
184 *
185 * @param snippetId the id of the snippet.
186 * @param line the line.
187 * @return True, if the line is a start demarcator.
188 */
189 protected boolean isStart( String snippetId, String line )
190 {
191 return isDemarcator( snippetId, "START", line );
192 }
193
194 /**
195 * Determines if the given line is a demarcator.
196 *
197 * @param snippetId the id of the snippet.
198 * @param what Identifier for the demarcator.
199 * @param line the line.
200 * @return True, if the line is a start demarcator.
201 */
202 protected boolean isDemarcator( String snippetId, String what, String line )
203 {
204 String upper = line.toUpperCase( Locale.ENGLISH );
205 return upper.contains( what.toUpperCase( Locale.ENGLISH ) )
206 && upper.contains( "SNIPPET" )
207 && line.contains( snippetId );
208 }
209
210 /**
211 * Determines if the given line is an end demarcator.
212 *
213 * @param snippetId the id of the snippet.
214 * @param line the line.
215 * @return True, if the line is an end demarcator.
216 */
217 protected boolean isEnd( String snippetId, String line )
218 {
219 return isDemarcator( snippetId, "END", line );
220 }
221 }