libjava/org/xml/sax/helpers/AttributesImpl.java

   1 // AttributesImpl.java - default implementation of Attributes.
   2 // http://www.saxproject.org
   3 // Written by David Megginson
   4 // NO WARRANTY!  This class is in the public domain.
   5
   6 // $Id: AttributesImpl.java,v 1.6.2.3 2002/01/29 21:34:14 dbrownell Exp $
   7
   8
   9 package org.xml.sax.helpers;
  10
  11 import org.xml.sax.Attributes;
  12
  13
  14 /**
  15  * Default implementation of the Attributes interface.
  16  *
  17  * <blockquote>
  18  * <em>This module, both source code and documentation, is in the
  19  * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
  20  * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
  21  * for further information.
  22  * </blockquote>
  23  *
  24  * <p>This class provides a default implementation of the SAX2
  25  * {@link org.xml.sax.Attributes Attributes} interface, with the
  26  * addition of manipulators so that the list can be modified or
  27  * reused.</p>
  28  *
  29  * <p>There are two typical uses of this class:</p>
  30  *
  31  * <ol>
  32  * <li>to take a persistent snapshot of an Attributes object
  33  *  in a {@link org.xml.sax.ContentHandler#startElement startElement} event; or</li>
  34  * <li>to construct or modify an Attributes object in a SAX2 driver or filter.</li>
  35  * </ol>
  36  *
  37  * <p>This class replaces the now-deprecated SAX1 {@link
  38  * org.xml.sax.helpers.AttributeListImpl AttributeListImpl}
  39  * class; in addition to supporting the updated Attributes
  40  * interface rather than the deprecated {@link org.xml.sax.AttributeList
  41  * AttributeList} interface, it also includes a much more efficient
  42  * implementation using a single array rather than a set of Vectors.</p>
  43  *
  44  * @since SAX 2.0
  45  * @author David Megginson
  46  * @version 2.0.1 (sax2r2)
  47  */
  48 public class AttributesImpl implements Attributes
  49 {
  50
  51 \f
  52     ////////////////////////////////////////////////////////////////////
  53     // Constructors.
  54     ////////////////////////////////////////////////////////////////////
  55
  56
  57     /**
  58      * Construct a new, empty AttributesImpl object.
  59      */
  60     public AttributesImpl ()
  61     {
  62         length = 0;
  63         data = null;
  64     }
  65
  66
  67     /**
  68      * Copy an existing Attributes object.
  69      *
  70      * <p>This constructor is especially useful inside a
  71      * {@link org.xml.sax.ContentHandler#startElement startElement} event.</p>
  72      *
  73      * @param atts The existing Attributes object.
  74      */
  75     public AttributesImpl (Attributes atts)
  76     {
  77         setAttributes(atts);
  78     }
  79
  80
  81 \f
  82     ////////////////////////////////////////////////////////////////////
  83     // Implementation of org.xml.sax.Attributes.
  84     ////////////////////////////////////////////////////////////////////
  85
  86
  87     /**
  88      * Return the number of attributes in the list.
  89      *
  90      * @return The number of attributes in the list.
  91      * @see org.xml.sax.Attributes#getLength
  92      */
  93     public int getLength ()
  94     {
  95         return length;
  96     }
  97
  98
  99     /**
 100      * Return an attribute's Namespace URI.
 101      *
 102      * @param index The attribute's index (zero-based).
 103      * @return The Namespace URI, the empty string if none is
 104      *         available, or null if the index is out of range.
 105      * @see org.xml.sax.Attributes#getURI
 106      */
 107     public String getURI (int index)
 108     {
 109         if (index >= 0 && index < length) {
 110             return data[index*5];
 111         } else {
 112             return null;
 113         }
 114     }
 115
 116
 117     /**
 118      * Return an attribute's local name.
 119      *
 120      * @param index The attribute's index (zero-based).
 121      * @return The attribute's local name, the empty string if
 122      *         none is available, or null if the index if out of range.
 123      * @see org.xml.sax.Attributes#getLocalName
 124      */
 125     public String getLocalName (int index)
 126     {
 127         if (index >= 0 && index < length) {
 128             return data[index*5+1];
 129         } else {
 130             return null;
 131         }
 132     }
 133
 134
 135     /**
 136      * Return an attribute's qualified (prefixed) name.
 137      *
 138      * @param index The attribute's index (zero-based).
 139      * @return The attribute's qualified name, the empty string if
 140      *         none is available, or null if the index is out of bounds.
 141      * @see org.xml.sax.Attributes#getQName
 142      */
 143     public String getQName (int index)
 144     {
 145         if (index >= 0 && index < length) {
 146             return data[index*5+2];
 147         } else {
 148             return null;
 149         }
 150     }
 151
 152
 153     /**
 154      * Return an attribute's type by index.
 155      *
 156      * @param index The attribute's index (zero-based).
 157      * @return The attribute's type, "CDATA" if the type is unknown, or null
 158      *         if the index is out of bounds.
 159      * @see org.xml.sax.Attributes#getType(int)
 160      */
 161     public String getType (int index)
 162     {
 163         if (index >= 0 && index < length) {
 164             return data[index*5+3];
 165         } else {
 166             return null;
 167         }
 168     }
 169
 170
 171     /**
 172      * Return an attribute's value by index.
 173      *
 174      * @param index The attribute's index (zero-based).
 175      * @return The attribute's value or null if the index is out of bounds.
 176      * @see org.xml.sax.Attributes#getValue(int)
 177      */
 178     public String getValue (int index)
 179     {
 180         if (index >= 0 && index < length) {
 181             return data[index*5+4];
 182         } else {
 183             return null;
 184         }
 185     }
 186
 187
 188     /**
 189      * Look up an attribute's index by Namespace name.
 190      *
 191      * <p>In many cases, it will be more efficient to look up the name once and
 192      * use the index query methods rather than using the name query methods
 193      * repeatedly.</p>
 194      *
 195      * @param uri The attribute's Namespace URI, or the empty
 196      *        string if none is available.
 197      * @param localName The attribute's local name.
 198      * @return The attribute's index, or -1 if none matches.
 199      * @see org.xml.sax.Attributes#getIndex(java.lang.String,java.lang.String)
 200      */
 201     public int getIndex (String uri, String localName)
 202     {
 203         int max = length * 5;
 204         for (int i = 0; i < max; i += 5) {
 205             if (data[i].equals(uri) && data[i+1].equals(localName)) {
 206                 return i / 5;
 207             }
 208         }
 209         return -1;
 210     }
 211
 212
 213     /**
 214      * Look up an attribute's index by qualified (prefixed) name.
 215      *
 216      * @param qName The qualified name.
 217      * @return The attribute's index, or -1 if none matches.
 218      * @see org.xml.sax.Attributes#getIndex(java.lang.String)
 219      */
 220     public int getIndex (String qName)
 221     {
 222         int max = length * 5;
 223         for (int i = 0; i < max; i += 5) {
 224             if (data[i+2].equals(qName)) {
 225                 return i / 5;
 226             }
 227         }
 228         return -1;
 229     }
 230
 231
 232     /**
 233      * Look up an attribute's type by Namespace-qualified name.
 234      *
 235      * @param uri The Namespace URI, or the empty string for a name
 236      *        with no explicit Namespace URI.
 237      * @param localName The local name.
 238      * @return The attribute's type, or null if there is no
 239      *         matching attribute.
 240      * @see org.xml.sax.Attributes#getType(java.lang.String,java.lang.String)
 241      */
 242     public String getType (String uri, String localName)
 243     {
 244         int max = length * 5;
 245         for (int i = 0; i < max; i += 5) {
 246             if (data[i].equals(uri) && data[i+1].equals(localName)) {
 247                 return data[i+3];
 248             }
 249         }
 250         return null;
 251     }
 252
 253
 254     /**
 255      * Look up an attribute's type by qualified (prefixed) name.
 256      *
 257      * @param qName The qualified name.
 258      * @return The attribute's type, or null if there is no
 259      *         matching attribute.
 260      * @see org.xml.sax.Attributes#getType(java.lang.String)
 261      */
 262     public String getType (String qName)
 263     {
 264         int max = length * 5;
 265         for (int i = 0; i < max; i += 5) {
 266             if (data[i+2].equals(qName)) {
 267                 return data[i+3];
 268             }
 269         }
 270         return null;
 271     }
 272
 273
 274     /**
 275      * Look up an attribute's value by Namespace-qualified name.
 276      *
 277      * @param uri The Namespace URI, or the empty string for a name
 278      *        with no explicit Namespace URI.
 279      * @param localName The local name.
 280      * @return The attribute's value, or null if there is no
 281      *         matching attribute.
 282      * @see org.xml.sax.Attributes#getValue(java.lang.String,java.lang.String)
 283      */
 284     public String getValue (String uri, String localName)
 285     {
 286         int max = length * 5;
 287         for (int i = 0; i < max; i += 5) {
 288             if (data[i].equals(uri) && data[i+1].equals(localName)) {
 289                 return data[i+4];
 290             }
 291         }
 292         return null;
 293     }
 294
 295
 296     /**
 297      * Look up an attribute's value by qualified (prefixed) name.
 298      *
 299      * @param qName The qualified name.
 300      * @return The attribute's value, or null if there is no
 301      *         matching attribute.
 302      * @see org.xml.sax.Attributes#getValue(java.lang.String)
 303      */
 304     public String getValue (String qName)
 305     {
 306         int max = length * 5;
 307         for (int i = 0; i < max; i += 5) {
 308             if (data[i+2].equals(qName)) {
 309                 return data[i+4];
 310             }
 311         }
 312         return null;
 313     }
 314
 315
 316 \f
 317     ////////////////////////////////////////////////////////////////////
 318     // Manipulators.
 319     ////////////////////////////////////////////////////////////////////
 320
 321
 322     /**
 323      * Clear the attribute list for reuse.
 324      *
 325      * <p>Note that little memory is freed by this call:
 326      * the current array is kept so it can be
 327      * reused.</p>
 328      */
 329     public void clear ()
 330     {
 331         if (data != null) {
 332             for (int i = 0; i < (length * 5); i++)
 333                 data [i] = null;
 334         }
 335         length = 0;
 336     }
 337
 338
 339     /**
 340      * Copy an entire Attributes object.
 341      *
 342      * <p>It may be more efficient to reuse an existing object
 343      * rather than constantly allocating new ones.</p>
 344      *
 345      * @param atts The attributes to copy.
 346      */
 347     public void setAttributes (Attributes atts)
 348     {
 349         clear();
 350         length = atts.getLength();
 351         if (length > 0) {
 352             data = new String[length*5];
 353             for (int i = 0; i < length; i++) {
 354                 data[i*5] = atts.getURI(i);
 355                 data[i*5+1] = atts.getLocalName(i);
 356                 data[i*5+2] = atts.getQName(i);
 357                 data[i*5+3] = atts.getType(i);
 358                 data[i*5+4] = atts.getValue(i);
 359             }
 360         }
 361     }
 362
 363
 364     /**
 365      * Add an attribute to the end of the list.
 366      *
 367      * <p>For the sake of speed, this method does no checking
 368      * to see if the attribute is already in the list: that is
 369      * the responsibility of the application.</p>
 370      *
 371      * @param uri The Namespace URI, or the empty string if
 372      *        none is available or Namespace processing is not
 373      *        being performed.
 374      * @param localName The local name, or the empty string if
 375      *        Namespace processing is not being performed.
 376      * @param qName The qualified (prefixed) name, or the empty string
 377      *        if qualified names are not available.
 378      * @param type The attribute type as a string.
 379      * @param value The attribute value.
 380      */
 381     public void addAttribute (String uri, String localName, String qName,
 382                               String type, String value)
 383     {
 384         ensureCapacity(length+1);
 385         data[length*5] = uri;
 386         data[length*5+1] = localName;
 387         data[length*5+2] = qName;
 388         data[length*5+3] = type;
 389         data[length*5+4] = value;
 390         length++;
 391     }
 392
 393
 394     /**
 395      * Set an attribute in the list.
 396      *
 397      * <p>For the sake of speed, this method does no checking
 398      * for name conflicts or well-formedness: such checks are the
 399      * responsibility of the application.</p>
 400      *
 401      * @param index The index of the attribute (zero-based).
 402      * @param uri The Namespace URI, or the empty string if
 403      *        none is available or Namespace processing is not
 404      *        being performed.
 405      * @param localName The local name, or the empty string if
 406      *        Namespace processing is not being performed.
 407      * @param qName The qualified name, or the empty string
 408      *        if qualified names are not available.
 409      * @param type The attribute type as a string.
 410      * @param value The attribute value.
 411      * @exception java.lang.ArrayIndexOutOfBoundsException When the
 412      *            supplied index does not point to an attribute
 413      *            in the list.
 414      */
 415     public void setAttribute (int index, String uri, String localName,
 416                               String qName, String type, String value)
 417     {
 418         if (index >= 0 && index < length) {
 419             data[index*5] = uri;
 420             data[index*5+1] = localName;
 421             data[index*5+2] = qName;
 422             data[index*5+3] = type;
 423             data[index*5+4] = value;
 424         } else {
 425             badIndex(index);
 426         }
 427     }
 428
 429
 430     /**
 431      * Remove an attribute from the list.
 432      *
 433      * @param index The index of the attribute (zero-based).
 434      * @exception java.lang.ArrayIndexOutOfBoundsException When the
 435      *            supplied index does not point to an attribute
 436      *            in the list.
 437      */
 438     public void removeAttribute (int index)
 439     {
 440         if (index >= 0 && index < length) {
 441             if (index < length - 1) {
 442                 System.arraycopy(data, (index+1)*5, data, index*5,
 443                                  (length-index-1)*5);
 444             }
 445             index = (length - 1) * 5;
 446             data [index++] = null;
 447             data [index++] = null;
 448             data [index++] = null;
 449             data [index++] = null;
 450             data [index] = null;
 451             length--;
 452         } else {
 453             badIndex(index);
 454         }
 455     }
 456
 457
 458     /**
 459      * Set the Namespace URI of a specific attribute.
 460      *
 461      * @param index The index of the attribute (zero-based).
 462      * @param uri The attribute's Namespace URI, or the empty
 463      *        string for none.
 464      * @exception java.lang.ArrayIndexOutOfBoundsException When the
 465      *            supplied index does not point to an attribute
 466      *            in the list.
 467      */
 468     public void setURI (int index, String uri)
 469     {
 470         if (index >= 0 && index < length) {
 471             data[index*5] = uri;
 472         } else {
 473             badIndex(index);
 474         }
 475     }
 476
 477
 478     /**
 479      * Set the local name of a specific attribute.
 480      *
 481      * @param index The index of the attribute (zero-based).
 482      * @param localName The attribute's local name, or the empty
 483      *        string for none.
 484      * @exception java.lang.ArrayIndexOutOfBoundsException When the
 485      *            supplied index does not point to an attribute
 486      *            in the list.
 487      */
 488     public void setLocalName (int index, String localName)
 489     {
 490         if (index >= 0 && index < length) {
 491             data[index*5+1] = localName;
 492         } else {
 493             badIndex(index);
 494         }
 495     }
 496
 497
 498     /**
 499      * Set the qualified name of a specific attribute.
 500      *
 501      * @param index The index of the attribute (zero-based).
 502      * @param qName The attribute's qualified name, or the empty
 503      *        string for none.
 504      * @exception java.lang.ArrayIndexOutOfBoundsException When the
 505      *            supplied index does not point to an attribute
 506      *            in the list.
 507      */
 508     public void setQName (int index, String qName)
 509     {
 510         if (index >= 0 && index < length) {
 511             data[index*5+2] = qName;
 512         } else {
 513             badIndex(index);
 514         }
 515     }
 516
 517
 518     /**
 519      * Set the type of a specific attribute.
 520      *
 521      * @param index The index of the attribute (zero-based).
 522      * @param type The attribute's type.
 523      * @exception java.lang.ArrayIndexOutOfBoundsException When the
 524      *            supplied index does not point to an attribute
 525      *            in the list.
 526      */
 527     public void setType (int index, String type)
 528     {
 529         if (index >= 0 && index < length) {
 530             data[index*5+3] = type;
 531         } else {
 532             badIndex(index);
 533         }
 534     }
 535
 536
 537     /**
 538      * Set the value of a specific attribute.
 539      *
 540      * @param index The index of the attribute (zero-based).
 541      * @param value The attribute's value.
 542      * @exception java.lang.ArrayIndexOutOfBoundsException When the
 543      *            supplied index does not point to an attribute
 544      *            in the list.
 545      */
 546     public void setValue (int index, String value)
 547     {
 548         if (index >= 0 && index < length) {
 549             data[index*5+4] = value;
 550         } else {
 551             badIndex(index);
 552         }
 553     }
 554
 555
 556 \f
 557     ////////////////////////////////////////////////////////////////////
 558     // Internal methods.
 559     ////////////////////////////////////////////////////////////////////
 560
 561
 562     /**
 563      * Ensure the internal array's capacity.
 564      *
 565      * @param n The minimum number of attributes that the array must
 566      *        be able to hold.
 567      */
 568     private void ensureCapacity (int n)    {
 569         if (n <= 0) {
 570             return;
 571         }
 572         int max;
 573         if (data == null || data.length == 0) {
 574             max = 25;
 575         }
 576         else if (data.length >= n * 5) {
 577             return;
 578         }
 579         else {
 580             max = data.length;
 581         }
 582         while (max < n * 5) {
 583             max *= 2;
 584         }
 585
 586         String newData[] = new String[max];
 587         if (length > 0) {
 588             System.arraycopy(data, 0, newData, 0, length*5);
 589         }
 590         data = newData;
 591     }
 592
 593
 594     /**
 595      * Report a bad array index in a manipulator.
 596      *
 597      * @param index The index to report.
 598      * @exception java.lang.ArrayIndexOutOfBoundsException Always.
 599      */
 600     private void badIndex (int index)
 601         throws ArrayIndexOutOfBoundsException
 602     {
 603         String msg =
 604             "Attempt to modify attribute at illegal index: " + index;
 605         throw new ArrayIndexOutOfBoundsException(msg);
 606     }
 607
 608
 609 \f
 610     ////////////////////////////////////////////////////////////////////
 611     // Internal state.
 612     ////////////////////////////////////////////////////////////////////
 613
 614     int length;
 615     String data [];
 616
 617 }
 618
 619 // end of AttributesImpl.java
 620