1 // NamespaceSupport.java - generic Namespace support for SAX.
2 // http://www.saxproject.org
3 // Written by David Megginson
4 // This class is in the Public Domain.  NO WARRANTY!
5 // $Id: NamespaceSupport.java,v 1.15 2004/04/26 17:34:35 dmegginson Exp $
6 
7 package org.xml.sax.helpers;
8 
9 import java.util.ArrayList;
10 import java.util.Collections;
11 import java.util.EmptyStackException;
12 import java.util.Enumeration;
13 import java.util.Hashtable;
14 
15 /**
16  * Encapsulate Namespace logic for use by applications using SAX,
17  * or internally by SAX drivers.
18  *
19  * <blockquote>
20  * <em>This module, both source code and documentation, is in the
21  * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
22  * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a>
23  * for further information.
24  * </blockquote>
25  *
26  * <p>This class encapsulates the logic of Namespace processing: it
27  * tracks the declarations currently in force for each context and
28  * automatically processes qualified XML names into their Namespace
29  * parts; it can also be used in reverse for generating XML qnames
30  * from Namespaces.</p>
31  *
32  * <p>Namespace support objects are reusable, but the reset method
33  * must be invoked between each session.</p>
34  *
35  * <p>Here is a simple session:</p>
36  *
37  * <pre>
38  * String parts[] = new String[3];
39  * NamespaceSupport support = new NamespaceSupport();
40  *
41  * support.pushContext();
42  * support.declarePrefix("", "http://www.w3.org/1999/xhtml");
43  * support.declarePrefix("dc", "http://www.purl.org/dc#");
44  *
45  * parts = support.processName("p", parts, false);
46  * System.out.println("Namespace URI: " + parts[0]);
47  * System.out.println("Local name: " + parts[1]);
48  * System.out.println("Raw name: " + parts[2]);
49  *
50  * parts = support.processName("dc:title", parts, false);
51  * System.out.println("Namespace URI: " + parts[0]);
52  * System.out.println("Local name: " + parts[1]);
53  * System.out.println("Raw name: " + parts[2]);
54  *
55  * support.popContext();
56  * </pre>
57  *
58  * <p>Note that this class is optimized for the use case where most
59  * elements do not contain Namespace declarations: if the same
60  * prefix/URI mapping is repeated for each context (for example), this
61  * class will be somewhat less efficient.</p>
62  *
63  * <p>Although SAX drivers (parsers) may choose to use this class to
64  * implement namespace handling, they are not required to do so.
65  * Applications must track namespace information themselves if they
66  * want to use namespace information.
67  *
68  * @since SAX 2.0
69  * @author David Megginson
70  * @version 2.0.1 (sax2r2)
71  */
72 public class NamespaceSupport
73 {
74 
75 
76     ////////////////////////////////////////////////////////////////////
77     // Constants.
78     ////////////////////////////////////////////////////////////////////
79 
80 
81     /**
82      * The XML Namespace URI as a constant.
83      * The value is <code>http://www.w3.org/XML/1998/namespace</code>
84      * as defined in the "Namespaces in XML" * recommendation.
85      *
86      * <p>This is the Namespace URI that is automatically mapped
87      * to the "xml" prefix.</p>
88      */
89     public static final String XMLNS =
90     "http://www.w3.org/XML/1998/namespace";
91 
92 
93     /**
94      * The namespace declaration URI as a constant.
95      * The value is <code>http://www.w3.org/xmlns/2000/</code>, as defined
96      * in a backwards-incompatible erratum to the "Namespaces in XML"
97      * recommendation.  Because that erratum postdated SAX2, SAX2 defaults
98      * to the original recommendation, and does not normally use this URI.
99      *
100      *
101      * <p>This is the Namespace URI that is optionally applied to
102      * <em>xmlns</em> and <em>xmlns:*</em> attributes, which are used to
103      * declare namespaces.  </p>
104      *
105      * @since SAX 2.1alpha
106      * @see #setNamespaceDeclUris
107      * @see #isNamespaceDeclUris
108      */
109     public static final String NSDECL =
110     "http://www.w3.org/xmlns/2000/";
111 
112 
113     /**
114      * An empty enumeration.
115      */
116     private static final Enumeration EMPTY_ENUMERATION = Collections.enumeration(Collections.emptyList());
117 
118 
119     ////////////////////////////////////////////////////////////////////
120     // Constructor.
121     ////////////////////////////////////////////////////////////////////
122 
123 
124     /**
125      * Create a new Namespace support object.
126      */
NamespaceSupport()127     public NamespaceSupport ()
128     {
129     reset();
130     }
131 
132 
133 
134     ////////////////////////////////////////////////////////////////////
135     // Context management.
136     ////////////////////////////////////////////////////////////////////
137 
138 
139     /**
140      * Reset this Namespace support object for reuse.
141      *
142      * <p>It is necessary to invoke this method before reusing the
143      * Namespace support object for a new session.  If namespace
144      * declaration URIs are to be supported, that flag must also
145      * be set to a non-default value.
146      * </p>
147      *
148      * @see #setNamespaceDeclUris
149      */
reset()150     public void reset ()
151     {
152     contexts = new Context[32];
153     namespaceDeclUris = false;
154     contextPos = 0;
155     contexts[contextPos] = currentContext = new Context();
156     currentContext.declarePrefix("xml", XMLNS);
157     }
158 
159 
160     /**
161      * Start a new Namespace context.
162      * The new context will automatically inherit
163      * the declarations of its parent context, but it will also keep
164      * track of which declarations were made within this context.
165      *
166      * <p>Event callback code should start a new context once per element.
167      * This means being ready to call this in either of two places.
168      * For elements that don't include namespace declarations, the
169      * <em>ContentHandler.startElement()</em> callback is the right place.
170      * For elements with such a declaration, it'd done in the first
171      * <em>ContentHandler.startPrefixMapping()</em> callback.
172      * A boolean flag can be used to
173      * track whether a context has been started yet.  When either of
174      * those methods is called, it checks the flag to see if a new context
175      * needs to be started.  If so, it starts the context and sets the
176      * flag.  After <em>ContentHandler.startElement()</em>
177      * does that, it always clears the flag.
178      *
179      * <p>Normally, SAX drivers would push a new context at the beginning
180      * of each XML element.  Then they perform a first pass over the
181      * attributes to process all namespace declarations, making
182      * <em>ContentHandler.startPrefixMapping()</em> callbacks.
183      * Then a second pass is made, to determine the namespace-qualified
184      * names for all attributes and for the element name.
185      * Finally all the information for the
186      * <em>ContentHandler.startElement()</em> callback is available,
187      * so it can then be made.
188      *
189      * <p>The Namespace support object always starts with a base context
190      * already in force: in this context, only the "xml" prefix is
191      * declared.</p>
192      *
193      * @see org.xml.sax.ContentHandler
194      * @see #popContext
195      */
pushContext()196     public void pushContext ()
197     {
198     int max = contexts.length;
199 
200     contexts [contextPos].declsOK = false;
201     contextPos++;
202 
203                 // Extend the array if necessary
204     if (contextPos >= max) {
205         Context newContexts[] = new Context[max*2];
206         System.arraycopy(contexts, 0, newContexts, 0, max);
207         max *= 2;
208         contexts = newContexts;
209     }
210 
211                 // Allocate the context if necessary.
212     currentContext = contexts[contextPos];
213     if (currentContext == null) {
214         contexts[contextPos] = currentContext = new Context();
215     }
216 
217                 // Set the parent, if any.
218     if (contextPos > 0) {
219         currentContext.setParent(contexts[contextPos - 1]);
220     }
221     }
222 
223 
224     /**
225      * Revert to the previous Namespace context.
226      *
227      * <p>Normally, you should pop the context at the end of each
228      * XML element.  After popping the context, all Namespace prefix
229      * mappings that were previously in force are restored.</p>
230      *
231      * <p>You must not attempt to declare additional Namespace
232      * prefixes after popping a context, unless you push another
233      * context first.</p>
234      *
235      * @see #pushContext
236      */
popContext()237     public void popContext ()
238     {
239     contexts[contextPos].clear();
240     contextPos--;
241     if (contextPos < 0) {
242         throw new EmptyStackException();
243     }
244     currentContext = contexts[contextPos];
245     }
246 
247 
248 
249     ////////////////////////////////////////////////////////////////////
250     // Operations within a context.
251     ////////////////////////////////////////////////////////////////////
252 
253 
254     /**
255      * Declare a Namespace prefix.  All prefixes must be declared
256      * before they are referenced.  For example, a SAX driver (parser)
257      * would scan an element's attributes
258      * in two passes:  first for namespace declarations,
259      * then a second pass using {@link #processName processName()} to
260      * interpret prefixes against (potentially redefined) prefixes.
261      *
262      * <p>This method declares a prefix in the current Namespace
263      * context; the prefix will remain in force until this context
264      * is popped, unless it is shadowed in a descendant context.</p>
265      *
266      * <p>To declare the default element Namespace, use the empty string as
267      * the prefix.</p>
268      *
269      * <p>Note that you must <em>not</em> declare a prefix after
270      * you've pushed and popped another Namespace context, or
271      * treated the declarations phase as complete by processing
272      * a prefixed name.</p>
273      *
274      * <p>Note that there is an asymmetry in this library: {@link
275      * #getPrefix getPrefix} will not return the "" prefix,
276      * even if you have declared a default element namespace.
277      * To check for a default namespace,
278      * you have to look it up explicitly using {@link #getURI getURI}.
279      * This asymmetry exists to make it easier to look up prefixes
280      * for attribute names, where the default prefix is not allowed.</p>
281      *
282      * @param prefix The prefix to declare, or the empty string to
283      *    indicate the default element namespace.  This may never have
284      *    the value "xml" or "xmlns".
285      * @param uri The Namespace URI to associate with the prefix.
286      * @return true if the prefix was legal, false otherwise
287      *
288      * @see #processName
289      * @see #getURI
290      * @see #getPrefix
291      */
declarePrefix(String prefix, String uri)292     public boolean declarePrefix (String prefix, String uri)
293     {
294     if (prefix.equals("xml") || prefix.equals("xmlns")) {
295         return false;
296     } else {
297         currentContext.declarePrefix(prefix, uri);
298         return true;
299     }
300     }
301 
302 
303     /**
304      * Process a raw XML qualified name, after all declarations in the
305      * current context have been handled by {@link #declarePrefix
306      * declarePrefix()}.
307      *
308      * <p>This method processes a raw XML qualified name in the
309      * current context by removing the prefix and looking it up among
310      * the prefixes currently declared.  The return value will be the
311      * array supplied by the caller, filled in as follows:</p>
312      *
313      * <dl>
314      * <dt>parts[0]</dt>
315      * <dd>The Namespace URI, or an empty string if none is
316      *  in use.</dd>
317      * <dt>parts[1]</dt>
318      * <dd>The local name (without prefix).</dd>
319      * <dt>parts[2]</dt>
320      * <dd>The original raw name.</dd>
321      * </dl>
322      *
323      * <p>All of the strings in the array will be internalized.  If
324      * the raw name has a prefix that has not been declared, then
325      * the return value will be null.</p>
326      *
327      * <p>Note that attribute names are processed differently than
328      * element names: an unprefixed element name will receive the
329      * default Namespace (if any), while an unprefixed attribute name
330      * will not.</p>
331      *
332      * @param qName The XML qualified name to be processed.
333      * @param parts An array supplied by the caller, capable of
334      *        holding at least three members.
335      * @param isAttribute A flag indicating whether this is an
336      *        attribute name (true) or an element name (false).
337      * @return The supplied array holding three internalized strings
338      *        representing the Namespace URI (or empty string), the
339      *        local name, and the XML qualified name; or null if there
340      *        is an undeclared prefix.
341      * @see #declarePrefix
342      * @see java.lang.String#intern */
processName(String qName, String parts[], boolean isAttribute)343     public String [] processName (String qName, String parts[],
344                   boolean isAttribute)
345     {
346     String myParts[] = currentContext.processName(qName, isAttribute);
347     if (myParts == null) {
348         return null;
349     } else {
350         parts[0] = myParts[0];
351         parts[1] = myParts[1];
352         parts[2] = myParts[2];
353         return parts;
354     }
355     }
356 
357 
358     /**
359      * Look up a prefix and get the currently-mapped Namespace URI.
360      *
361      * <p>This method looks up the prefix in the current context.
362      * Use the empty string ("") for the default Namespace.</p>
363      *
364      * @param prefix The prefix to look up.
365      * @return The associated Namespace URI, or null if the prefix
366      *         is undeclared in this context.
367      * @see #getPrefix
368      * @see #getPrefixes
369      */
getURI(String prefix)370     public String getURI (String prefix)
371     {
372     return currentContext.getURI(prefix);
373     }
374 
375 
376     /**
377      * Return an enumeration of all prefixes whose declarations are
378      * active in the current context.
379      * This includes declarations from parent contexts that have
380      * not been overridden.
381      *
382      * <p><strong>Note:</strong> if there is a default prefix, it will not be
383      * returned in this enumeration; check for the default prefix
384      * using the {@link #getURI getURI} with an argument of "".</p>
385      *
386      * @return An enumeration of prefixes (never empty).
387      * @see #getDeclaredPrefixes
388      * @see #getURI
389      */
getPrefixes()390     public Enumeration getPrefixes ()
391     {
392     return currentContext.getPrefixes();
393     }
394 
395 
396     /**
397      * Return one of the prefixes mapped to a Namespace URI.
398      *
399      * <p>If more than one prefix is currently mapped to the same
400      * URI, this method will make an arbitrary selection; if you
401      * want all of the prefixes, use the {@link #getPrefixes}
402      * method instead.</p>
403      *
404      * <p><strong>Note:</strong> this will never return the empty (default) prefix;
405      * to check for a default prefix, use the {@link #getURI getURI}
406      * method with an argument of "".</p>
407      *
408      * @param uri the namespace URI
409      * @return one of the prefixes currently mapped to the URI supplied,
410      *         or null if none is mapped or if the URI is assigned to
411      *         the default namespace
412      * @see #getPrefixes(java.lang.String)
413      * @see #getURI
414      */
getPrefix(String uri)415     public String getPrefix (String uri)
416     {
417     return currentContext.getPrefix(uri);
418     }
419 
420 
421     /**
422      * Return an enumeration of all prefixes for a given URI whose
423      * declarations are active in the current context.
424      * This includes declarations from parent contexts that have
425      * not been overridden.
426      *
427      * <p>This method returns prefixes mapped to a specific Namespace
428      * URI.  The xml: prefix will be included.  If you want only one
429      * prefix that's mapped to the Namespace URI, and you don't care
430      * which one you get, use the {@link #getPrefix getPrefix}
431      *  method instead.</p>
432      *
433      * <p><strong>Note:</strong> the empty (default) prefix is <em>never</em> included
434      * in this enumeration; to check for the presence of a default
435      * Namespace, use the {@link #getURI getURI} method with an
436      * argument of "".</p>
437      *
438      * @param uri The Namespace URI.
439      * @return An enumeration of prefixes (never empty).
440      * @see #getPrefix
441      * @see #getDeclaredPrefixes
442      * @see #getURI
443      */
getPrefixes(String uri)444     public Enumeration getPrefixes(String uri) {
445         ArrayList<String> prefixes = new ArrayList<String>();
446         Enumeration allPrefixes = getPrefixes();
447         while (allPrefixes.hasMoreElements()) {
448             String prefix = (String) allPrefixes.nextElement();
449             if (uri.equals(getURI(prefix))) {
450                 prefixes.add(prefix);
451             }
452         }
453         return Collections.enumeration(prefixes);
454     }
455 
456 
457     /**
458      * Return an enumeration of all prefixes declared in this context.
459      *
460      * <p>The empty (default) prefix will be included in this
461      * enumeration; note that this behaviour differs from that of
462      * {@link #getPrefix} and {@link #getPrefixes}.</p>
463      *
464      * @return An enumeration of all prefixes declared in this
465      *         context.
466      * @see #getPrefixes
467      * @see #getURI
468      */
getDeclaredPrefixes()469     public Enumeration getDeclaredPrefixes ()
470     {
471     return currentContext.getDeclaredPrefixes();
472     }
473 
474     /**
475      * Controls whether namespace declaration attributes are placed
476      * into the {@link #NSDECL NSDECL} namespace
477      * by {@link #processName processName()}.  This may only be
478      * changed before any contexts have been pushed.
479      *
480      * @param value the namespace declaration attribute state. A value of true
481      *              enables this feature, a value of false disables it.
482      *
483      * @since SAX 2.1alpha
484      *
485      * @exception IllegalStateException when attempting to set this
486      *    after any context has been pushed.
487      */
setNamespaceDeclUris(boolean value)488     public void setNamespaceDeclUris (boolean value)
489     {
490     if (contextPos != 0)
491         throw new IllegalStateException ();
492     if (value == namespaceDeclUris)
493         return;
494     namespaceDeclUris = value;
495     if (value)
496         currentContext.declarePrefix ("xmlns", NSDECL);
497     else {
498         contexts[contextPos] = currentContext = new Context();
499         currentContext.declarePrefix("xml", XMLNS);
500     }
501     }
502 
503     /**
504      * Returns true if namespace declaration attributes are placed into
505      * a namespace.  This behavior is not the default.
506      *
507      * @return true if namespace declaration attributes are enabled, false
508      *         otherwise.
509      * @since SAX 2.1alpha
510      */
isNamespaceDeclUris()511     public boolean isNamespaceDeclUris ()
512     { return namespaceDeclUris; }
513 
514 
515 
516     ////////////////////////////////////////////////////////////////////
517     // Internal state.
518     ////////////////////////////////////////////////////////////////////
519 
520     private Context contexts[];
521     private Context currentContext;
522     private int contextPos;
523     private boolean namespaceDeclUris;
524 
525 
526     ////////////////////////////////////////////////////////////////////
527     // Internal classes.
528     ////////////////////////////////////////////////////////////////////
529 
530     /**
531      * Internal class for a single Namespace context.
532      *
533      * <p>This module caches and reuses Namespace contexts,
534      * so the number allocated
535      * will be equal to the element depth of the document, not to the total
536      * number of elements (i.e. 5-10 rather than tens of thousands).
537      * Also, data structures used to represent contexts are shared when
538      * possible (child contexts without declarations) to further reduce
539      * the amount of memory that's consumed.
540      * </p>
541      */
542     final class Context {
543 
544     /**
545      * Create the root-level Namespace context.
546      */
Context()547     Context ()
548     {
549         copyTables();
550     }
551 
552 
553     /**
554      * (Re)set the parent of this Namespace context.
555      * The context must either have been freshly constructed,
556      * or must have been cleared.
557      *
558      * @param context The parent Namespace context object.
559      */
setParent(Context parent)560     void setParent (Context parent)
561     {
562         this.parent = parent;
563         declarations = null;
564         prefixTable = parent.prefixTable;
565         uriTable = parent.uriTable;
566         elementNameTable = parent.elementNameTable;
567         attributeNameTable = parent.attributeNameTable;
568         defaultNS = parent.defaultNS;
569         declSeen = false;
570         declsOK = true;
571     }
572 
573     /**
574      * Makes associated state become collectible,
575      * invalidating this context.
576      * {@link #setParent} must be called before
577      * this context may be used again.
578      */
clear()579     void clear ()
580     {
581         parent = null;
582         prefixTable = null;
583         uriTable = null;
584         elementNameTable = null;
585         attributeNameTable = null;
586         defaultNS = null;
587     }
588 
589 
590     /**
591      * Declare a Namespace prefix for this context.
592      *
593      * @param prefix The prefix to declare.
594      * @param uri The associated Namespace URI.
595      * @see org.xml.sax.helpers.NamespaceSupport#declarePrefix
596      */
declarePrefix(String prefix, String uri)597     void declarePrefix(String prefix, String uri) {
598         // Lazy processing...
599         if (!declsOK) {
600             throw new IllegalStateException ("can't declare any more prefixes in this context");
601         }
602         if (!declSeen) {
603             copyTables();
604         }
605         if (declarations == null) {
606             declarations = new ArrayList<String>();
607         }
608 
609         prefix = prefix.intern();
610         uri = uri.intern();
611         if ("".equals(prefix)) {
612             if ("".equals(uri)) {
613                 defaultNS = null;
614             } else {
615                 defaultNS = uri;
616             }
617         } else {
618             prefixTable.put(prefix, uri);
619             uriTable.put(uri, prefix); // may wipe out another prefix
620         }
621         declarations.add(prefix);
622     }
623 
624 
625     /**
626      * Process an XML qualified name in this context.
627      *
628      * @param qName The XML qualified name.
629      * @param isAttribute true if this is an attribute name.
630      * @return An array of three strings containing the
631      *         URI part (or empty string), the local part,
632      *         and the raw name, all internalized, or null
633      *         if there is an undeclared prefix.
634      * @see org.xml.sax.helpers.NamespaceSupport#processName
635      */
processName(String qName, boolean isAttribute)636     String [] processName (String qName, boolean isAttribute)
637     {
638         String name[];
639         Hashtable table;
640 
641                     // detect errors in call sequence
642         declsOK = false;
643 
644                 // Select the appropriate table.
645         if (isAttribute) {
646         table = attributeNameTable;
647         } else {
648         table = elementNameTable;
649         }
650 
651                 // Start by looking in the cache, and
652                 // return immediately if the name
653                 // is already known in this content
654         name = (String[])table.get(qName);
655         if (name != null) {
656         return name;
657         }
658 
659                 // We haven't seen this name in this
660                 // context before.  Maybe in the parent
661                 // context, but we can't assume prefix
662                 // bindings are the same.
663         name = new String[3];
664         name[2] = qName.intern();
665         int index = qName.indexOf(':');
666 
667 
668                 // No prefix.
669         if (index == -1) {
670         if (isAttribute) {
671             if (qName == "xmlns" && namespaceDeclUris)
672             name[0] = NSDECL;
673             else
674             name[0] = "";
675         } else if (defaultNS == null) {
676             name[0] = "";
677         } else {
678             name[0] = defaultNS;
679         }
680         name[1] = name[2];
681         }
682 
683                 // Prefix
684         else {
685         String prefix = qName.substring(0, index);
686         String local = qName.substring(index+1);
687         String uri;
688         if ("".equals(prefix)) {
689             uri = defaultNS;
690         } else {
691             uri = (String)prefixTable.get(prefix);
692         }
693         if (uri == null
694             || (!isAttribute && "xmlns".equals (prefix))) {
695             return null;
696         }
697         name[0] = uri;
698         name[1] = local.intern();
699         }
700 
701                 // Save in the cache for future use.
702                 // (Could be shared with parent context...)
703         table.put(name[2], name);
704         return name;
705     }
706 
707 
708     /**
709      * Look up the URI associated with a prefix in this context.
710      *
711      * @param prefix The prefix to look up.
712      * @return The associated Namespace URI, or null if none is
713      *         declared.
714      * @see org.xml.sax.helpers.NamespaceSupport#getURI
715      */
getURI(String prefix)716     String getURI (String prefix)
717     {
718         if ("".equals(prefix)) {
719         return defaultNS;
720         } else if (prefixTable == null) {
721         return null;
722         } else {
723         return (String)prefixTable.get(prefix);
724         }
725     }
726 
727 
728     /**
729      * Look up one of the prefixes associated with a URI in this context.
730      *
731      * <p>Since many prefixes may be mapped to the same URI,
732      * the return value may be unreliable.</p>
733      *
734      * @param uri The URI to look up.
735      * @return The associated prefix, or null if none is declared.
736      * @see org.xml.sax.helpers.NamespaceSupport#getPrefix
737      */
getPrefix(String uri)738     String getPrefix (String uri)
739     {
740         if (uriTable == null) {
741         return null;
742         } else {
743         return (String)uriTable.get(uri);
744         }
745     }
746 
747 
748     /**
749      * Return an enumeration of prefixes declared in this context.
750      *
751      * @return An enumeration of prefixes (possibly empty).
752      * @see org.xml.sax.helpers.NamespaceSupport#getDeclaredPrefixes
753      */
getDeclaredPrefixes()754     Enumeration getDeclaredPrefixes() {
755         return (declarations == null) ? EMPTY_ENUMERATION : Collections.enumeration(declarations);
756     }
757 
758 
759     /**
760      * Return an enumeration of all prefixes currently in force.
761      *
762      * <p>The default prefix, if in force, is <em>not</em>
763      * returned, and will have to be checked for separately.</p>
764      *
765      * @return An enumeration of prefixes (never empty).
766      * @see org.xml.sax.helpers.NamespaceSupport#getPrefixes
767      */
getPrefixes()768     Enumeration getPrefixes ()
769     {
770         if (prefixTable == null) {
771         return EMPTY_ENUMERATION;
772         } else {
773         return prefixTable.keys();
774         }
775     }
776 
777 
778 
779     ////////////////////////////////////////////////////////////////
780     // Internal methods.
781     ////////////////////////////////////////////////////////////////
782 
783 
784     /**
785      * Copy on write for the internal tables in this context.
786      *
787      * <p>This class is optimized for the normal case where most
788      * elements do not contain Namespace declarations.</p>
789      */
copyTables()790     private void copyTables ()
791     {
792         if (prefixTable != null) {
793         prefixTable = (Hashtable)prefixTable.clone();
794         } else {
795         prefixTable = new Hashtable();
796         }
797         if (uriTable != null) {
798         uriTable = (Hashtable)uriTable.clone();
799         } else {
800         uriTable = new Hashtable();
801         }
802         elementNameTable = new Hashtable();
803         attributeNameTable = new Hashtable();
804         declSeen = true;
805     }
806 
807 
808 
809     ////////////////////////////////////////////////////////////////
810     // Protected state.
811     ////////////////////////////////////////////////////////////////
812 
813     Hashtable prefixTable;
814     Hashtable uriTable;
815     Hashtable elementNameTable;
816     Hashtable attributeNameTable;
817     String defaultNS = null;
818     boolean declsOK = true;
819 
820 
821 
822     ////////////////////////////////////////////////////////////////
823     // Internal state.
824     ////////////////////////////////////////////////////////////////
825 
826     private ArrayList<String> declarations = null;
827     private boolean declSeen = false;
828     private Context parent = null;
829     }
830 }
831 
832 // end of NamespaceSupport.java
833