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1: // DefaultHandler.java - default implementation of the core handlers. 2: // http://www.saxproject.org 3: // Written by David Megginson 4: // NO WARRANTY! This class is in the public domain. 5: // $Id: DefaultHandler.java,v 1.1 2004/12/23 22:38:42 mark Exp $ 6: 7: package org.xml.sax.helpers; 8: 9: import java.io.IOException; 10: 11: import org.xml.sax.InputSource; 12: import org.xml.sax.Locator; 13: import org.xml.sax.Attributes; 14: import org.xml.sax.EntityResolver; 15: import org.xml.sax.DTDHandler; 16: import org.xml.sax.ContentHandler; 17: import org.xml.sax.ErrorHandler; 18: import org.xml.sax.SAXException; 19: import org.xml.sax.SAXParseException; 20: 21: 22: /** 23: * Default base class for SAX2 event handlers. 24: * 25: * <blockquote> 26: * <em>This module, both source code and documentation, is in the 27: * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em> 28: * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a> 29: * for further information. 30: * </blockquote> 31: * 32: * <p>This class is available as a convenience base class for SAX2 33: * applications: it provides default implementations for all of the 34: * callbacks in the four core SAX2 handler classes:</p> 35: * 36: * <ul> 37: * <li>{@link org.xml.sax.EntityResolver EntityResolver}</li> 38: * <li>{@link org.xml.sax.DTDHandler DTDHandler}</li> 39: * <li>{@link org.xml.sax.ContentHandler ContentHandler}</li> 40: * <li>{@link org.xml.sax.ErrorHandler ErrorHandler}</li> 41: * </ul> 42: * 43: * <p>Application writers can extend this class when they need to 44: * implement only part of an interface; parser writers can 45: * instantiate this class to provide default handlers when the 46: * application has not supplied its own.</p> 47: * 48: * <p>This class replaces the deprecated SAX1 49: * {@link org.xml.sax.HandlerBase HandlerBase} class.</p> 50: * 51: * @since SAX 2.0 52: * @author David Megginson, 53: * @version 2.0.1 (sax2r2) 54: * @see org.xml.sax.EntityResolver 55: * @see org.xml.sax.DTDHandler 56: * @see org.xml.sax.ContentHandler 57: * @see org.xml.sax.ErrorHandler 58: */ 59: public class DefaultHandler 60: implements EntityResolver, DTDHandler, ContentHandler, ErrorHandler 61: { 62: 63: 64: //////////////////////////////////////////////////////////////////// 65: // Default implementation of the EntityResolver interface. 66: //////////////////////////////////////////////////////////////////// 67: 68: /** 69: * Resolve an external entity. 70: * 71: * <p>Always return null, so that the parser will use the system 72: * identifier provided in the XML document. This method implements 73: * the SAX default behaviour: application writers can override it 74: * in a subclass to do special translations such as catalog lookups 75: * or URI redirection.</p> 76: * 77: * @param publicId The public identifer, or null if none is 78: * available. 79: * @param systemId The system identifier provided in the XML 80: * document. 81: * @return The new input source, or null to require the 82: * default behaviour. 83: * @exception java.io.IOException If there is an error setting 84: * up the new input source. 85: * @exception org.xml.sax.SAXException Any SAX exception, possibly 86: * wrapping another exception. 87: * @see org.xml.sax.EntityResolver#resolveEntity 88: */ 89: public InputSource resolveEntity (String publicId, String systemId) 90: throws IOException, SAXException 91: { 92: return null; 93: } 94: 95: 96: 97: //////////////////////////////////////////////////////////////////// 98: // Default implementation of DTDHandler interface. 99: //////////////////////////////////////////////////////////////////// 100: 101: 102: /** 103: * Receive notification of a notation declaration. 104: * 105: * <p>By default, do nothing. Application writers may override this 106: * method in a subclass if they wish to keep track of the notations 107: * declared in a document.</p> 108: * 109: * @param name The notation name. 110: * @param publicId The notation public identifier, or null if not 111: * available. 112: * @param systemId The notation system identifier. 113: * @exception org.xml.sax.SAXException Any SAX exception, possibly 114: * wrapping another exception. 115: * @see org.xml.sax.DTDHandler#notationDecl 116: */ 117: public void notationDecl (String name, String publicId, String systemId) 118: throws SAXException 119: { 120: // no op 121: } 122: 123: 124: /** 125: * Receive notification of an unparsed entity declaration. 126: * 127: * <p>By default, do nothing. Application writers may override this 128: * method in a subclass to keep track of the unparsed entities 129: * declared in a document.</p> 130: * 131: * @param name The entity name. 132: * @param publicId The entity public identifier, or null if not 133: * available. 134: * @param systemId The entity system identifier. 135: * @param notationName The name of the associated notation. 136: * @exception org.xml.sax.SAXException Any SAX exception, possibly 137: * wrapping another exception. 138: * @see org.xml.sax.DTDHandler#unparsedEntityDecl 139: */ 140: public void unparsedEntityDecl (String name, String publicId, 141: String systemId, String notationName) 142: throws SAXException 143: { 144: // no op 145: } 146: 147: 148: 149: //////////////////////////////////////////////////////////////////// 150: // Default implementation of ContentHandler interface. 151: //////////////////////////////////////////////////////////////////// 152: 153: 154: /** 155: * Receive a Locator object for document events. 156: * 157: * <p>By default, do nothing. Application writers may override this 158: * method in a subclass if they wish to store the locator for use 159: * with other document events.</p> 160: * 161: * @param locator A locator for all SAX document events. 162: * @see org.xml.sax.ContentHandler#setDocumentLocator 163: * @see org.xml.sax.Locator 164: */ 165: public void setDocumentLocator (Locator locator) 166: { 167: // no op 168: } 169: 170: 171: /** 172: * Receive notification of the beginning of the document. 173: * 174: * <p>By default, do nothing. Application writers may override this 175: * method in a subclass to take specific actions at the beginning 176: * of a document (such as allocating the root node of a tree or 177: * creating an output file).</p> 178: * 179: * @exception org.xml.sax.SAXException Any SAX exception, possibly 180: * wrapping another exception. 181: * @see org.xml.sax.ContentHandler#startDocument 182: */ 183: public void startDocument () 184: throws SAXException 185: { 186: // no op 187: } 188: 189: 190: /** 191: * Receive notification of the end of the document. 192: * 193: * <p>By default, do nothing. Application writers may override this 194: * method in a subclass to take specific actions at the end 195: * of a document (such as finalising a tree or closing an output 196: * file).</p> 197: * 198: * @exception org.xml.sax.SAXException Any SAX exception, possibly 199: * wrapping another exception. 200: * @see org.xml.sax.ContentHandler#endDocument 201: */ 202: public void endDocument () 203: throws SAXException 204: { 205: // no op 206: } 207: 208: 209: /** 210: * Receive notification of the start of a Namespace mapping. 211: * 212: * <p>By default, do nothing. Application writers may override this 213: * method in a subclass to take specific actions at the start of 214: * each Namespace prefix scope (such as storing the prefix mapping).</p> 215: * 216: * @param prefix The Namespace prefix being declared. 217: * @param uri The Namespace URI mapped to the prefix. 218: * @exception org.xml.sax.SAXException Any SAX exception, possibly 219: * wrapping another exception. 220: * @see org.xml.sax.ContentHandler#startPrefixMapping 221: */ 222: public void startPrefixMapping (String prefix, String uri) 223: throws SAXException 224: { 225: // no op 226: } 227: 228: 229: /** 230: * Receive notification of the end of a Namespace mapping. 231: * 232: * <p>By default, do nothing. Application writers may override this 233: * method in a subclass to take specific actions at the end of 234: * each prefix mapping.</p> 235: * 236: * @param prefix The Namespace prefix being declared. 237: * @exception org.xml.sax.SAXException Any SAX exception, possibly 238: * wrapping another exception. 239: * @see org.xml.sax.ContentHandler#endPrefixMapping 240: */ 241: public void endPrefixMapping (String prefix) 242: throws SAXException 243: { 244: // no op 245: } 246: 247: 248: /** 249: * Receive notification of the start of an element. 250: * 251: * <p>By default, do nothing. Application writers may override this 252: * method in a subclass to take specific actions at the start of 253: * each element (such as allocating a new tree node or writing 254: * output to a file).</p> 255: * 256: * @param uri The Namespace URI, or the empty string if the 257: * element has no Namespace URI or if Namespace 258: * processing is not being performed. 259: * @param localName The local name (without prefix), or the 260: * empty string if Namespace processing is not being 261: * performed. 262: * @param qName The qualified name (with prefix), or the 263: * empty string if qualified names are not available. 264: * @param attributes The attributes attached to the element. If 265: * there are no attributes, it shall be an empty 266: * Attributes object. 267: * @exception org.xml.sax.SAXException Any SAX exception, possibly 268: * wrapping another exception. 269: * @see org.xml.sax.ContentHandler#startElement 270: */ 271: public void startElement (String uri, String localName, 272: String qName, Attributes attributes) 273: throws SAXException 274: { 275: // no op 276: } 277: 278: 279: /** 280: * Receive notification of the end of an element. 281: * 282: * <p>By default, do nothing. Application writers may override this 283: * method in a subclass to take specific actions at the end of 284: * each element (such as finalising a tree node or writing 285: * output to a file).</p> 286: * 287: * @param uri The Namespace URI, or the empty string if the 288: * element has no Namespace URI or if Namespace 289: * processing is not being performed. 290: * @param localName The local name (without prefix), or the 291: * empty string if Namespace processing is not being 292: * performed. 293: * @param qName The qualified name (with prefix), or the 294: * empty string if qualified names are not available. 295: * @exception org.xml.sax.SAXException Any SAX exception, possibly 296: * wrapping another exception. 297: * @see org.xml.sax.ContentHandler#endElement 298: */ 299: public void endElement (String uri, String localName, String qName) 300: throws SAXException 301: { 302: // no op 303: } 304: 305: 306: /** 307: * Receive notification of character data inside an element. 308: * 309: * <p>By default, do nothing. Application writers may override this 310: * method to take specific actions for each chunk of character data 311: * (such as adding the data to a node or buffer, or printing it to 312: * a file).</p> 313: * 314: * @param ch The characters. 315: * @param start The start position in the character array. 316: * @param length The number of characters to use from the 317: * character array. 318: * @exception org.xml.sax.SAXException Any SAX exception, possibly 319: * wrapping another exception. 320: * @see org.xml.sax.ContentHandler#characters 321: */ 322: public void characters (char ch[], int start, int length) 323: throws SAXException 324: { 325: // no op 326: } 327: 328: 329: /** 330: * Receive notification of ignorable whitespace in element content. 331: * 332: * <p>By default, do nothing. Application writers may override this 333: * method to take specific actions for each chunk of ignorable 334: * whitespace (such as adding data to a node or buffer, or printing 335: * it to a file).</p> 336: * 337: * @param ch The whitespace characters. 338: * @param start The start position in the character array. 339: * @param length The number of characters to use from the 340: * character array. 341: * @exception org.xml.sax.SAXException Any SAX exception, possibly 342: * wrapping another exception. 343: * @see org.xml.sax.ContentHandler#ignorableWhitespace 344: */ 345: public void ignorableWhitespace (char ch[], int start, int length) 346: throws SAXException 347: { 348: // no op 349: } 350: 351: 352: /** 353: * Receive notification of a processing instruction. 354: * 355: * <p>By default, do nothing. Application writers may override this 356: * method in a subclass to take specific actions for each 357: * processing instruction, such as setting status variables or 358: * invoking other methods.</p> 359: * 360: * @param target The processing instruction target. 361: * @param data The processing instruction data, or null if 362: * none is supplied. 363: * @exception org.xml.sax.SAXException Any SAX exception, possibly 364: * wrapping another exception. 365: * @see org.xml.sax.ContentHandler#processingInstruction 366: */ 367: public void processingInstruction (String target, String data) 368: throws SAXException 369: { 370: // no op 371: } 372: 373: 374: /** 375: * Receive notification of a skipped entity. 376: * 377: * <p>By default, do nothing. Application writers may override this 378: * method in a subclass to take specific actions for each 379: * processing instruction, such as setting status variables or 380: * invoking other methods.</p> 381: * 382: * @param name The name of the skipped entity. 383: * @exception org.xml.sax.SAXException Any SAX exception, possibly 384: * wrapping another exception. 385: * @see org.xml.sax.ContentHandler#processingInstruction 386: */ 387: public void skippedEntity (String name) 388: throws SAXException 389: { 390: // no op 391: } 392: 393: 394: 395: //////////////////////////////////////////////////////////////////// 396: // Default implementation of the ErrorHandler interface. 397: //////////////////////////////////////////////////////////////////// 398: 399: 400: /** 401: * Receive notification of a parser warning. 402: * 403: * <p>The default implementation does nothing. Application writers 404: * may override this method in a subclass to take specific actions 405: * for each warning, such as inserting the message in a log file or 406: * printing it to the console.</p> 407: * 408: * @param e The warning information encoded as an exception. 409: * @exception org.xml.sax.SAXException Any SAX exception, possibly 410: * wrapping another exception. 411: * @see org.xml.sax.ErrorHandler#warning 412: * @see org.xml.sax.SAXParseException 413: */ 414: public void warning (SAXParseException e) 415: throws SAXException 416: { 417: // no op 418: } 419: 420: 421: /** 422: * Receive notification of a recoverable parser error. 423: * 424: * <p>The default implementation does nothing. Application writers 425: * may override this method in a subclass to take specific actions 426: * for each error, such as inserting the message in a log file or 427: * printing it to the console.</p> 428: * 429: * @param e The warning information encoded as an exception. 430: * @exception org.xml.sax.SAXException Any SAX exception, possibly 431: * wrapping another exception. 432: * @see org.xml.sax.ErrorHandler#warning 433: * @see org.xml.sax.SAXParseException 434: */ 435: public void error (SAXParseException e) 436: throws SAXException 437: { 438: // no op 439: } 440: 441: 442: /** 443: * Report a fatal XML parsing error. 444: * 445: * <p>The default implementation throws a SAXParseException. 446: * Application writers may override this method in a subclass if 447: * they need to take specific actions for each fatal error (such as 448: * collecting all of the errors into a single report): in any case, 449: * the application must stop all regular processing when this 450: * method is invoked, since the document is no longer reliable, and 451: * the parser may no longer report parsing events.</p> 452: * 453: * @param e The error information encoded as an exception. 454: * @exception org.xml.sax.SAXException Any SAX exception, possibly 455: * wrapping another exception. 456: * @see org.xml.sax.ErrorHandler#fatalError 457: * @see org.xml.sax.SAXParseException 458: */ 459: public void fatalError (SAXParseException e) 460: throws SAXException 461: { 462: throw e; 463: } 464: 465: } 466: 467: // end of DefaultHandler.java