| 1 | /* |
| 2 | * Copyright (C) Christian Schulte, 2005-206 |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * |
| 9 | * o Redistributions of source code must retain the above copyright |
| 10 | * notice, this list of conditions and the following disclaimer. |
| 11 | * |
| 12 | * o Redistributions in binary form must reproduce the above copyright |
| 13 | * notice, this list of conditions and the following disclaimer in |
| 14 | * the documentation and/or other materials provided with the |
| 15 | * distribution. |
| 16 | * |
| 17 | * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, |
| 18 | * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY |
| 19 | * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL |
| 20 | * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | * |
| 28 | * $JOMC: SectionEditor.java 4613 2012-09-22 10:07:08Z schulte $ |
| 29 | * |
| 30 | */ |
| 31 | package org.jomc.util; |
| 32 | |
| 33 | import java.io.IOException; |
| 34 | import java.text.MessageFormat; |
| 35 | import java.util.HashMap; |
| 36 | import java.util.Map; |
| 37 | import java.util.ResourceBundle; |
| 38 | import java.util.Stack; |
| 39 | |
| 40 | /** |
| 41 | * Interface to section based editing. |
| 42 | * <p>Section based editing is a two phase process of parsing the editor's input into a corresponding hierarchy of |
| 43 | * {@code Section} instances, followed by rendering the parsed sections to produce the output of the editor. Method |
| 44 | * {@code editLine} returns {@code null} during parsing and the output of the editor on end of input, rendered by |
| 45 | * calling method {@code getOutput}. Parsing is backed by methods {@code getSection} and {@code isSectionFinished}.</p> |
| 46 | * |
| 47 | * @author <a href="mailto:cs@schulte.it">Christian Schulte</a> |
| 48 | * @version $JOMC: SectionEditor.java 4613 2012-09-22 10:07:08Z schulte $ |
| 49 | * |
| 50 | * @see #edit(java.lang.String) |
| 51 | */ |
| 52 | public class SectionEditor extends LineEditor |
| 53 | { |
| 54 | |
| 55 | /** Marker indicating the start of a section. */ |
| 56 | private static final String DEFAULT_SECTION_START = "SECTION-START["; |
| 57 | |
| 58 | /** Marker indicating the end of a section. */ |
| 59 | private static final String DEFAULT_SECTION_END = "SECTION-END"; |
| 60 | |
| 61 | /** Stack of sections. */ |
| 62 | private Stack<Section> stack; |
| 63 | |
| 64 | /** Mapping of section names to flags indicating presence of the section. */ |
| 65 | private final Map<String, Boolean> presenceFlags = new HashMap<String, Boolean>(); |
| 66 | |
| 67 | /** Creates a new {@code SectionEditor} instance. */ |
| 68 | public SectionEditor() |
| 69 | { |
| 70 | this( null, null ); |
| 71 | } |
| 72 | |
| 73 | /** |
| 74 | * Creates a new {@code SectionEditor} instance taking a string to use for separating lines. |
| 75 | * |
| 76 | * @param lineSeparator String to use for separating lines. |
| 77 | */ |
| 78 | public SectionEditor( final String lineSeparator ) |
| 79 | { |
| 80 | this( null, lineSeparator ); |
| 81 | } |
| 82 | |
| 83 | /** |
| 84 | * Creates a new {@code SectionEditor} instance taking an editor to chain. |
| 85 | * |
| 86 | * @param editor The editor to chain. |
| 87 | */ |
| 88 | public SectionEditor( final LineEditor editor ) |
| 89 | { |
| 90 | this( editor, null ); |
| 91 | } |
| 92 | |
| 93 | /** |
| 94 | * Creates a new {@code SectionEditor} instance taking an editor to chain and a string to use for separating lines. |
| 95 | * |
| 96 | * @param editor The editor to chain. |
| 97 | * @param lineSeparator String to use for separating lines. |
| 98 | */ |
| 99 | public SectionEditor( final LineEditor editor, final String lineSeparator ) |
| 100 | { |
| 101 | super( editor, lineSeparator ); |
| 102 | } |
| 103 | |
| 104 | @Override |
| 105 | protected final String editLine( final String line ) throws IOException |
| 106 | { |
| 107 | if ( this.stack == null ) |
| 108 | { |
| 109 | final Section root = new Section(); |
| 110 | root.setMode( Section.MODE_HEAD ); |
| 111 | this.stack = new Stack<Section>(); |
| 112 | this.stack.push( root ); |
| 113 | } |
| 114 | |
| 115 | Section current = this.stack.peek(); |
| 116 | String replacement = null; |
| 117 | |
| 118 | if ( line != null ) |
| 119 | { |
| 120 | final Section child = this.getSection( line ); |
| 121 | |
| 122 | if ( child != null ) |
| 123 | { |
| 124 | child.setStartingLine( line ); |
| 125 | child.setMode( Section.MODE_HEAD ); |
| 126 | |
| 127 | if ( current.getMode() == Section.MODE_TAIL && current.getTailContent().length() > 0 ) |
| 128 | { |
| 129 | final Section s = new Section(); |
| 130 | s.getHeadContent().append( current.getTailContent() ); |
| 131 | current.getTailContent().setLength( 0 ); |
| 132 | current.getSections().add( s ); |
| 133 | current = s; |
| 134 | this.stack.push( current ); |
| 135 | } |
| 136 | |
| 137 | current.getSections().add( child ); |
| 138 | current.setMode( Section.MODE_TAIL ); |
| 139 | this.stack.push( child ); |
| 140 | } |
| 141 | else if ( this.isSectionFinished( line ) ) |
| 142 | { |
| 143 | final Section s = this.stack.pop(); |
| 144 | s.setEndingLine( line ); |
| 145 | |
| 146 | if ( this.stack.isEmpty() ) |
| 147 | { |
| 148 | this.stack = null; |
| 149 | throw new IOException( getMessage( "unexpectedEndOfSection", this.getLineNumber() ) ); |
| 150 | } |
| 151 | |
| 152 | if ( this.stack.peek().getName() == null && this.stack.size() > 1 ) |
| 153 | { |
| 154 | this.stack.pop(); |
| 155 | } |
| 156 | } |
| 157 | else |
| 158 | { |
| 159 | switch ( current.getMode() ) |
| 160 | { |
| 161 | case Section.MODE_HEAD: |
| 162 | current.getHeadContent().append( line ).append( this.getLineSeparator() ); |
| 163 | break; |
| 164 | |
| 165 | case Section.MODE_TAIL: |
| 166 | current.getTailContent().append( line ).append( this.getLineSeparator() ); |
| 167 | break; |
| 168 | |
| 169 | default: |
| 170 | throw new AssertionError( current.getMode() ); |
| 171 | |
| 172 | } |
| 173 | } |
| 174 | } |
| 175 | else |
| 176 | { |
| 177 | final Section root = this.stack.pop(); |
| 178 | |
| 179 | if ( !this.stack.isEmpty() ) |
| 180 | { |
| 181 | this.stack = null; |
| 182 | throw new IOException( getMessage( "unexpectedEndOfFile", this.getLineNumber(), root.getName() ) ); |
| 183 | } |
| 184 | |
| 185 | replacement = this.getOutput( root ); |
| 186 | this.stack = null; |
| 187 | } |
| 188 | |
| 189 | return replacement; |
| 190 | } |
| 191 | |
| 192 | /** |
| 193 | * Parses the given line to mark the start of a new section. |
| 194 | * |
| 195 | * @param line The line to parse or {@code null}. |
| 196 | * |
| 197 | * @return The section starting at {@code line} or {@code null}, if {@code line} does not mark the start of a |
| 198 | * section. |
| 199 | * |
| 200 | * @throws IOException if parsing fails. |
| 201 | */ |
| 202 | protected Section getSection( final String line ) throws IOException |
| 203 | { |
| 204 | Section s = null; |
| 205 | |
| 206 | if ( line != null ) |
| 207 | { |
| 208 | final int markerIndex = line.indexOf( DEFAULT_SECTION_START ); |
| 209 | |
| 210 | if ( markerIndex != -1 ) |
| 211 | { |
| 212 | final int startIndex = markerIndex + DEFAULT_SECTION_START.length(); |
| 213 | final int endIndex = line.indexOf( ']', startIndex ); |
| 214 | |
| 215 | if ( endIndex == -1 ) |
| 216 | { |
| 217 | throw new IOException( getMessage( "sectionMarkerParseFailure", line, this.getLineNumber() ) ); |
| 218 | } |
| 219 | |
| 220 | s = new Section(); |
| 221 | s.setName( line.substring( startIndex, endIndex ) ); |
| 222 | } |
| 223 | } |
| 224 | |
| 225 | return s; |
| 226 | } |
| 227 | |
| 228 | /** |
| 229 | * Parses the given line to mark the end of a section. |
| 230 | * |
| 231 | * @param line The line to parse or {@code null}. |
| 232 | * |
| 233 | * @return {@code true}, if {@code line} marks the end of a section; {@code false}, if {@code line} does not mark |
| 234 | * the end of a section. |
| 235 | * |
| 236 | * @throws IOException if parsing fails. |
| 237 | */ |
| 238 | protected boolean isSectionFinished( final String line ) throws IOException |
| 239 | { |
| 240 | return line != null && line.indexOf( DEFAULT_SECTION_END ) != -1; |
| 241 | } |
| 242 | |
| 243 | /** |
| 244 | * Edits a section. |
| 245 | * <p>This method does not change any content by default. Overriding classes may use this method for editing |
| 246 | * sections prior to rendering.</p> |
| 247 | * |
| 248 | * @param section The section to edit. |
| 249 | * |
| 250 | * @throws NullPointerException if {@code section} is {@code null}. |
| 251 | * @throws IOException if editing fails. |
| 252 | */ |
| 253 | protected void editSection( final Section section ) throws IOException |
| 254 | { |
| 255 | if ( section == null ) |
| 256 | { |
| 257 | throw new NullPointerException( "section" ); |
| 258 | } |
| 259 | |
| 260 | if ( section.getName() != null ) |
| 261 | { |
| 262 | this.presenceFlags.put( section.getName(), Boolean.TRUE ); |
| 263 | } |
| 264 | } |
| 265 | |
| 266 | /** |
| 267 | * Edits a section recursively. |
| 268 | * |
| 269 | * @param section The section to edit recursively. |
| 270 | * |
| 271 | * @throws NullPointerException if {@code section} is {@code null}. |
| 272 | * @throws IOException if editing fails. |
| 273 | */ |
| 274 | private void editSections( final Section section ) throws IOException |
| 275 | { |
| 276 | if ( section == null ) |
| 277 | { |
| 278 | throw new NullPointerException( "section" ); |
| 279 | } |
| 280 | |
| 281 | this.editSection( section ); |
| 282 | for ( int i = 0, s0 = section.getSections().size(); i < s0; i++ ) |
| 283 | { |
| 284 | this.editSections( section.getSections().get( i ) ); |
| 285 | } |
| 286 | } |
| 287 | |
| 288 | /** |
| 289 | * Gets the output of the editor. |
| 290 | * <p>This method calls method {@code editSection()} for each section of the editor prior to rendering the sections |
| 291 | * to produce the output of the editor.</p> |
| 292 | * |
| 293 | * @param section The section to start rendering the editor's output with. |
| 294 | * |
| 295 | * @return The output of the editor. |
| 296 | * |
| 297 | * @throws NullPointerException if {@code section} is {@code null}. |
| 298 | * @throws IOException if editing or rendering fails. |
| 299 | */ |
| 300 | protected String getOutput( final Section section ) throws IOException |
| 301 | { |
| 302 | if ( section == null ) |
| 303 | { |
| 304 | throw new NullPointerException( "section" ); |
| 305 | } |
| 306 | |
| 307 | this.presenceFlags.clear(); |
| 308 | this.editSections( section ); |
| 309 | return this.renderSections( section, new StringBuilder( 512 ) ).toString(); |
| 310 | } |
| 311 | |
| 312 | /** |
| 313 | * Gets a flag indicating that the input of the editor contained a named section. |
| 314 | * |
| 315 | * @param sectionName The name of the section to test or {@code null}. |
| 316 | * |
| 317 | * @return {@code true}, if the input of the editor contained a section with name {@code sectionName}; |
| 318 | * {@code false}, if the input of the editor did not contain a section with name {@code sectionName}. |
| 319 | */ |
| 320 | public boolean isSectionPresent( final String sectionName ) |
| 321 | { |
| 322 | return sectionName != null && this.presenceFlags.get( sectionName ) != null |
| 323 | && this.presenceFlags.get( sectionName ).booleanValue(); |
| 324 | |
| 325 | } |
| 326 | |
| 327 | /** |
| 328 | * Appends the content of a given section to a given buffer. |
| 329 | * |
| 330 | * @param section The section to render. |
| 331 | * @param buffer The buffer to append the content of {@code section} to. |
| 332 | * |
| 333 | * @return {@code buffer} with content of {@code section} appended. |
| 334 | */ |
| 335 | private StringBuilder renderSections( final Section section, final StringBuilder buffer ) |
| 336 | { |
| 337 | if ( section.getStartingLine() != null ) |
| 338 | { |
| 339 | buffer.append( section.getStartingLine() ).append( this.getLineSeparator() ); |
| 340 | } |
| 341 | |
| 342 | buffer.append( section.getHeadContent() ); |
| 343 | |
| 344 | for ( int i = 0, s0 = section.getSections().size(); i < s0; i++ ) |
| 345 | { |
| 346 | this.renderSections( section.getSections().get( i ), buffer ); |
| 347 | } |
| 348 | |
| 349 | buffer.append( section.getTailContent() ); |
| 350 | |
| 351 | if ( section.getEndingLine() != null ) |
| 352 | { |
| 353 | buffer.append( section.getEndingLine() ).append( this.getLineSeparator() ); |
| 354 | } |
| 355 | |
| 356 | return buffer; |
| 357 | } |
| 358 | |
| 359 | private static String getMessage( final String key, final Object... arguments ) |
| 360 | { |
| 361 | return MessageFormat.format( ResourceBundle.getBundle( SectionEditor.class.getName(). |
| 362 | replace( '.', '/' ) ).getString( key ), arguments ); |
| 363 | |
| 364 | } |
| 365 | |
| 366 | } |