diff options
Diffstat (limited to 'libjava/org/xml/sax/helpers/NamespaceSupport.java')
-rw-r--r-- | libjava/org/xml/sax/helpers/NamespaceSupport.java | 1459 |
1 files changed, 770 insertions, 689 deletions
diff --git a/libjava/org/xml/sax/helpers/NamespaceSupport.java b/libjava/org/xml/sax/helpers/NamespaceSupport.java index a4588c3d2c7..917a7f75dce 100644 --- a/libjava/org/xml/sax/helpers/NamespaceSupport.java +++ b/libjava/org/xml/sax/helpers/NamespaceSupport.java @@ -1,689 +1,770 @@ -// NamespaceSupport.java - generic Namespace support for SAX.
-// Written by David Megginson, sax@megginson.com
-// This class is in the Public Domain. NO WARRANTY!
-
-// $Id: NamespaceSupport.java,v 1.1 2000/10/02 02:43:20 sboag Exp $
-
-package org.xml.sax.helpers;
-
-import java.util.EmptyStackException;
-import java.util.Enumeration;
-import java.util.Hashtable;
-import java.util.Vector;
-
-
-/**
- * Encapsulate Namespace logic for use by SAX drivers.
- *
- * <blockquote>
- * <em>This module, both source code and documentation, is in the
- * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em>
- * </blockquote>
- *
- * <p>This class encapsulates the logic of Namespace processing:
- * it tracks the declarations currently in force for each context
- * and automatically processes qualified XML 1.0 names into their
- * Namespace parts; it can also be used in reverse for generating
- * XML 1.0 from Namespaces.</p>
- *
- * <p>Namespace support objects are reusable, but the reset method
- * must be invoked between each session.</p>
- *
- * <p>Here is a simple session:</p>
- *
- * <pre>
- * String parts[] = new String[3];
- * NamespaceSupport support = new NamespaceSupport();
- *
- * support.pushContext();
- * support.declarePrefix("", "http://www.w3.org/1999/xhtml");
- * support.declarePrefix("dc", "http://www.purl.org/dc#");
- *
- * String parts[] = support.processName("p", parts, false);
- * System.out.println("Namespace URI: " + parts[0]);
- * System.out.println("Local name: " + parts[1]);
- * System.out.println("Raw name: " + parts[2]);
-
- * String parts[] = support.processName("dc:title", parts, false);
- * System.out.println("Namespace URI: " + parts[0]);
- * System.out.println("Local name: " + parts[1]);
- * System.out.println("Raw name: " + parts[2]);
-
- * support.popContext();
- * </pre>
- *
- * <p>Note that this class is optimized for the use case where most
- * elements do not contain Namespace declarations: if the same
- * prefix/URI mapping is repeated for each context (for example), this
- * class will be somewhat less efficient.</p>
- *
- * @since SAX 2.0
- * @author David Megginson,
- * <a href="mailto:sax@megginson.com">sax@megginson.com</a>
- * @version 2.0
- */
-public class NamespaceSupport
-{
-
-
- ////////////////////////////////////////////////////////////////////
- // Constants.
- ////////////////////////////////////////////////////////////////////
-
-
- /**
- * The XML Namespace as a constant.
- *
- * <p>This is the Namespace URI that is automatically mapped
- * to the "xml" prefix.</p>
- */
- public final static String XMLNS =
- "http://www.w3.org/XML/1998/namespace";
-
-
- /**
- * An empty enumeration.
- */
- private final static Enumeration EMPTY_ENUMERATION =
- new Vector().elements();
-
-
- ////////////////////////////////////////////////////////////////////
- // Constructor.
- ////////////////////////////////////////////////////////////////////
-
-
- /**
- * Create a new Namespace support object.
- */
- public NamespaceSupport ()
- {
- reset();
- }
-
-
-
- ////////////////////////////////////////////////////////////////////
- // Context management.
- ////////////////////////////////////////////////////////////////////
-
-
- /**
- * Reset this Namespace support object for reuse.
- *
- * <p>It is necessary to invoke this method before reusing the
- * Namespace support object for a new session.</p>
- */
- public void reset ()
- {
- contexts = new Context[32];
- contextPos = 0;
- contexts[contextPos] = currentContext = new Context();
- currentContext.declarePrefix("xml", XMLNS);
- }
-
-
- /**
- * Start a new Namespace context.
- *
- * <p>Normally, you should push a new context at the beginning
- * of each XML element: the new context will automatically inherit
- * the declarations of its parent context, but it will also keep
- * track of which declarations were made within this context.</p>
- *
- * <p>The Namespace support object always starts with a base context
- * already in force: in this context, only the "xml" prefix is
- * declared.</p>
- *
- * @see #popContext
- */
- public void pushContext ()
- {
- int max = contexts.length;
- contextPos++;
-
- // Extend the array if necessary
- if (contextPos >= max) {
- Context newContexts[] = new Context[max*2];
- System.arraycopy(contexts, 0, newContexts, 0, max);
- max *= 2;
- contexts = newContexts;
- }
-
- // Allocate the context if necessary.
- currentContext = contexts[contextPos];
- if (currentContext == null) {
- contexts[contextPos] = currentContext = new Context();
- }
-
- // Set the parent, if any.
- if (contextPos > 0) {
- currentContext.setParent(contexts[contextPos - 1]);
- }
- }
-
-
- /**
- * Revert to the previous Namespace context.
- *
- * <p>Normally, you should pop the context at the end of each
- * XML element. After popping the context, all Namespace prefix
- * mappings that were previously in force are restored.</p>
- *
- * <p>You must not attempt to declare additional Namespace
- * prefixes after popping a context, unless you push another
- * context first.</p>
- *
- * @see #pushContext
- */
- public void popContext ()
- {
- contextPos--;
- if (contextPos < 0) {
- throw new EmptyStackException();
- }
- currentContext = contexts[contextPos];
- }
-
-
-
- ////////////////////////////////////////////////////////////////////
- // Operations within a context.
- ////////////////////////////////////////////////////////////////////
-
-
- /**
- * Declare a Namespace prefix.
- *
- * <p>This method declares a prefix in the current Namespace
- * context; the prefix will remain in force until this context
- * is popped, unless it is shadowed in a descendant context.</p>
- *
- * <p>To declare a default Namespace, use the empty string. The
- * prefix must not be "xml" or "xmlns".</p>
- *
- * <p>Note that you must <em>not</em> declare a prefix after
- * you've pushed and popped another Namespace.</p>
- *
- * <p>Note that there is an asymmetry in this library: while {@link
- * #getPrefix getPrefix} will not return the default "" prefix,
- * even if you have declared one; to check for a default prefix,
- * you have to look it up explicitly using {@link #getURI getURI}.
- * This asymmetry exists to make it easier to look up prefixes
- * for attribute names, where the default prefix is not allowed.</p>
- *
- * @param prefix The prefix to declare, or null for the empty
- * string.
- * @param uri The Namespace URI to associate with the prefix.
- * @return true if the prefix was legal, false otherwise
- * @see #processName
- * @see #getURI
- * @see #getPrefix
- */
- public boolean declarePrefix (String prefix, String uri)
- {
- if (prefix.equals("xml") || prefix.equals("xmlns")) {
- return false;
- } else {
- currentContext.declarePrefix(prefix, uri);
- return true;
- }
- }
-
-
- /**
- * Process a raw XML 1.0 name.
- *
- * <p>This method processes a raw XML 1.0 name in the current
- * context by removing the prefix and looking it up among the
- * prefixes currently declared. The return value will be the
- * array supplied by the caller, filled in as follows:</p>
- *
- * <dl>
- * <dt>parts[0]</dt>
- * <dd>The Namespace URI, or an empty string if none is
- * in use.</dd>
- * <dt>parts[1]</dt>
- * <dd>The local name (without prefix).</dd>
- * <dt>parts[2]</dt>
- * <dd>The original raw name.</dd>
- * </dl>
- *
- * <p>All of the strings in the array will be internalized. If
- * the raw name has a prefix that has not been declared, then
- * the return value will be null.</p>
- *
- * <p>Note that attribute names are processed differently than
- * element names: an unprefixed element name will received the
- * default Namespace (if any), while an unprefixed element name
- * will not.</p>
- *
- * @param qName The raw XML 1.0 name to be processed.
- * @param parts An array supplied by the caller, capable of
- * holding at least three members.
- * @param isAttribute A flag indicating whether this is an
- * attribute name (true) or an element name (false).
- * @return The supplied array holding three internalized strings
- * representing the Namespace URI (or empty string), the
- * local name, and the raw XML 1.0 name; or null if there
- * is an undeclared prefix.
- * @see #declarePrefix
- * @see java.lang.String#intern */
- public String [] processName (String qName, String parts[],
- boolean isAttribute)
- {
- String myParts[] = currentContext.processName(qName, isAttribute);
- if (myParts == null) {
- return null;
- } else {
- parts[0] = myParts[0];
- parts[1] = myParts[1];
- parts[2] = myParts[2];
- return parts;
- }
- }
-
-
- /**
- * Look up a prefix and get the currently-mapped Namespace URI.
- *
- * <p>This method looks up the prefix in the current context.
- * Use the empty string ("") for the default Namespace.</p>
- *
- * @param prefix The prefix to look up.
- * @return The associated Namespace URI, or null if the prefix
- * is undeclared in this context.
- * @see #getPrefix
- * @see #getPrefixes
- */
- public String getURI (String prefix)
- {
- return currentContext.getURI(prefix);
- }
-
-
- /**
- * Return an enumeration of all prefixes currently declared.
- *
- * <p><strong>Note:</strong> if there is a default prefix, it will not be
- * returned in this enumeration; check for the default prefix
- * using the {@link #getURI getURI} with an argument of "".</p>
- *
- * @return An enumeration of all prefixes declared in the
- * current context except for the empty (default)
- * prefix.
- * @see #getDeclaredPrefixes
- * @see #getURI
- */
- public Enumeration getPrefixes ()
- {
- return currentContext.getPrefixes();
- }
-
-
- /**
- * Return one of the prefixes mapped to a Namespace URI.
- *
- * <p>If more than one prefix is currently mapped to the same
- * URI, this method will make an arbitrary selection; if you
- * want all of the prefixes, use the {@link #getPrefixes}
- * method instead.</p>
- *
- * <p><strong>Note:</strong> this will never return the empty (default) prefix;
- * to check for a default prefix, use the {@link #getURI getURI}
- * method with an argument of "".</p>
- *
- * @param uri The Namespace URI.
- * @param isAttribute true if this prefix is for an attribute
- * (and the default Namespace is not allowed).
- * @return One of the prefixes currently mapped to the URI supplied,
- * or null if none is mapped or if the URI is assigned to
- * the default Namespace.
- * @see #getPrefixes(java.lang.String)
- * @see #getURI
- */
- public String getPrefix (String uri)
- {
- return currentContext.getPrefix(uri);
- }
-
-
- /**
- * Return an enumeration of all prefixes currently declared for a URI.
- *
- * <p>This method returns prefixes mapped to a specific Namespace
- * URI. The xml: prefix will be included. If you want only one
- * prefix that's mapped to the Namespace URI, and you don't care
- * which one you get, use the {@link #getPrefix getPrefix}
- * method instead.</p>
- *
- * <p><strong>Note:</strong> the empty (default) prefix is <em>never</em> included
- * in this enumeration; to check for the presence of a default
- * Namespace, use the {@link #getURI getURI} method with an
- * argument of "".</p>
- *
- * @param uri The Namespace URI.
- * @return An enumeration of all prefixes declared in the
- * current context.
- * @see #getPrefix
- * @see #getDeclaredPrefixes
- * @see #getURI
- */
- public Enumeration getPrefixes (String uri)
- {
- Vector prefixes = new Vector();
- Enumeration allPrefixes = getPrefixes();
- while (allPrefixes.hasMoreElements()) {
- String prefix = (String)allPrefixes.nextElement();
- if (uri.equals(getURI(prefix))) {
- prefixes.addElement(prefix);
- }
- }
- return prefixes.elements();
- }
-
-
- /**
- * Return an enumeration of all prefixes declared in this context.
- *
- * <p>The empty (default) prefix will be included in this
- * enumeration; note that this behaviour differs from that of
- * {@link #getPrefix} and {@link #getPrefixes}.</p>
- *
- * @return An enumeration of all prefixes declared in this
- * context.
- * @see #getPrefixes
- * @see #getURI
- */
- public Enumeration getDeclaredPrefixes ()
- {
- return currentContext.getDeclaredPrefixes();
- }
-
-
-
- ////////////////////////////////////////////////////////////////////
- // Internal state.
- ////////////////////////////////////////////////////////////////////
-
- private Context contexts[];
- private Context currentContext;
- private int contextPos;
-
-
-
- ////////////////////////////////////////////////////////////////////
- // Internal classes.
- ////////////////////////////////////////////////////////////////////
-
- /**
- * Internal class for a single Namespace context.
- *
- * <p>This module caches and reuses Namespace contexts, so the number allocated
- * will be equal to the element depth of the document, not to the total
- * number of elements (i.e. 5-10 rather than tens of thousands).</p>
- */
- final class Context {
-
- /**
- * Create the root-level Namespace context.
- */
- Context ()
- {
- copyTables();
- }
-
-
- /**
- * (Re)set the parent of this Namespace context.
- *
- * @param context The parent Namespace context object.
- */
- void setParent (Context parent)
- {
- this.parent = parent;
- declarations = null;
- prefixTable = parent.prefixTable;
- uriTable = parent.uriTable;
- elementNameTable = parent.elementNameTable;
- attributeNameTable = parent.attributeNameTable;
- defaultNS = parent.defaultNS;
- tablesDirty = false;
- }
-
-
- /**
- * Declare a Namespace prefix for this context.
- *
- * @param prefix The prefix to declare.
- * @param uri The associated Namespace URI.
- * @see org.xml.sax.helpers.NamespaceSupport#declarePrefix
- */
- void declarePrefix (String prefix, String uri)
- {
- // Lazy processing...
- if (!tablesDirty) {
- copyTables();
- }
- if (declarations == null) {
- declarations = new Vector();
- }
-
- prefix = prefix.intern();
- uri = uri.intern();
- if ("".equals(prefix)) {
- if ("".equals(uri)) {
- defaultNS = null;
- } else {
- defaultNS = uri;
- }
- } else {
- prefixTable.put(prefix, uri);
- uriTable.put(uri, prefix); // may wipe out another prefix
- }
- declarations.addElement(prefix);
- }
-
-
- /**
- * Process a raw XML 1.0 name in this context.
- *
- * @param qName The raw XML 1.0 name.
- * @param isAttribute true if this is an attribute name.
- * @return An array of three strings containing the
- * URI part (or empty string), the local part,
- * and the raw name, all internalized, or null
- * if there is an undeclared prefix.
- * @see org.xml.sax.helpers.NamespaceSupport#processName
- */
- String [] processName (String qName, boolean isAttribute)
- {
- String name[];
- Hashtable table;
-
- // Select the appropriate table.
- if (isAttribute) {
- table = elementNameTable;
- } else {
- table = attributeNameTable;
- }
-
- // Start by looking in the cache, and
- // return immediately if the name
- // is already known in this content
- name = (String[])table.get(qName);
- if (name != null) {
- return name;
- }
-
- // We haven't seen this name in this
- // context before.
- name = new String[3];
- int index = qName.indexOf(':');
-
-
- // No prefix.
- if (index == -1) {
- if (isAttribute || defaultNS == null) {
- name[0] = "";
- } else {
- name[0] = defaultNS;
- }
- name[1] = qName.intern();
- name[2] = name[1];
- }
-
- // Prefix
- else {
- String prefix = qName.substring(0, index);
- String local = qName.substring(index+1);
- String uri;
- if ("".equals(prefix)) {
- uri = defaultNS;
- } else {
- uri = (String)prefixTable.get(prefix);
- }
- if (uri == null) {
- return null;
- }
- name[0] = uri;
- name[1] = local.intern();
- name[2] = qName.intern();
- }
-
- // Save in the cache for future use.
- table.put(name[2], name);
- tablesDirty = true;
- return name;
- }
-
-
- /**
- * Look up the URI associated with a prefix in this context.
- *
- * @param prefix The prefix to look up.
- * @return The associated Namespace URI, or null if none is
- * declared.
- * @see org.xml.sax.helpers.NamespaceSupport#getURI
- */
- String getURI (String prefix)
- {
- if ("".equals(prefix)) {
- return defaultNS;
- } else if (prefixTable == null) {
- return null;
- } else {
- return (String)prefixTable.get(prefix);
- }
- }
-
-
- /**
- * Look up one of the prefixes associated with a URI in this context.
- *
- * <p>Since many prefixes may be mapped to the same URI,
- * the return value may be unreliable.</p>
- *
- * @param uri The URI to look up.
- * @return The associated prefix, or null if none is declared.
- * @see org.xml.sax.helpers.NamespaceSupport#getPrefix
- */
- String getPrefix (String uri)
- {
- if (uriTable == null) {
- return null;
- } else {
- return (String)uriTable.get(uri);
- }
- }
-
-
- /**
- * Return an enumeration of prefixes declared in this context.
- *
- * @return An enumeration of prefixes (possibly empty).
- * @see org.xml.sax.helpers.NamespaceSupport#getDeclaredPrefixes
- */
- Enumeration getDeclaredPrefixes ()
- {
- if (declarations == null) {
- return EMPTY_ENUMERATION;
- } else {
- return declarations.elements();
- }
- }
-
-
- /**
- * Return an enumeration of all prefixes currently in force.
- *
- * <p>The default prefix, if in force, is <em>not</em>
- * returned, and will have to be checked for separately.</p>
- *
- * @return An enumeration of prefixes (never empty).
- * @see org.xml.sax.helpers.NamespaceSupport#getPrefixes
- */
- Enumeration getPrefixes ()
- {
- if (prefixTable == null) {
- return EMPTY_ENUMERATION;
- } else {
- return prefixTable.keys();
- }
- }
-
-
-
- ////////////////////////////////////////////////////////////////
- // Internal methods.
- ////////////////////////////////////////////////////////////////
-
-
- /**
- * Copy on write for the internal tables in this context.
- *
- * <p>This class is optimized for the normal case where most
- * elements do not contain Namespace declarations.</p>
- */
- private void copyTables ()
- {
- if (prefixTable != null) {
- prefixTable = (Hashtable)prefixTable.clone();
- } else {
- prefixTable = new Hashtable();
- }
- if (uriTable != null) {
- uriTable = (Hashtable)uriTable.clone();
- } else {
- uriTable = new Hashtable();
- }
- elementNameTable = new Hashtable();
- attributeNameTable = new Hashtable();
- tablesDirty = true;
- }
-
-
-
- ////////////////////////////////////////////////////////////////
- // Protected state.
- ////////////////////////////////////////////////////////////////
-
- Hashtable prefixTable;
- Hashtable uriTable;
- Hashtable elementNameTable;
- Hashtable attributeNameTable;
- String defaultNS = null;
-
-
-
- ////////////////////////////////////////////////////////////////
- // Internal state.
- ////////////////////////////////////////////////////////////////
-
- private Vector declarations = null;
- private boolean tablesDirty = false;
- private Context parent = null;
- }
-}
-
-// end of NamespaceSupport.java
+// NamespaceSupport.java - generic Namespace support for SAX. +// http://www.saxproject.org +// Written by David Megginson +// This class is in the Public Domain. NO WARRANTY! + +// $Id: NamespaceSupport.java,v 1.6.2.5 2002/01/29 21:34:14 dbrownell Exp $ + +package org.xml.sax.helpers; + +import java.util.EmptyStackException; +import java.util.Enumeration; +import java.util.Hashtable; +import java.util.Vector; + + +/** + * Encapsulate Namespace logic for use by applications using SAX, + * or internally by SAX drivers. + * + * <blockquote> + * <em>This module, both source code and documentation, is in the + * Public Domain, and comes with <strong>NO WARRANTY</strong>.</em> + * See <a href='http://www.saxproject.org'>http://www.saxproject.org</a> + * for further information. + * </blockquote> + * + * <p>This class encapsulates the logic of Namespace processing: + * it tracks the declarations currently in force for each context + * and automatically processes qualified XML 1.0 names into their + * Namespace parts; it can also be used in reverse for generating + * XML 1.0 from Namespaces.</p> + * + * <p>Namespace support objects are reusable, but the reset method + * must be invoked between each session.</p> + * + * <p>Here is a simple session:</p> + * + * <pre> + * String parts[] = new String[3]; + * NamespaceSupport support = new NamespaceSupport(); + * + * support.pushContext(); + * support.declarePrefix("", "http://www.w3.org/1999/xhtml"); + * support.declarePrefix("dc", "http://www.purl.org/dc#"); + * + * parts = support.processName("p", parts, false); + * System.out.println("Namespace URI: " + parts[0]); + * System.out.println("Local name: " + parts[1]); + * System.out.println("Raw name: " + parts[2]); + * + * parts = support.processName("dc:title", parts, false); + * System.out.println("Namespace URI: " + parts[0]); + * System.out.println("Local name: " + parts[1]); + * System.out.println("Raw name: " + parts[2]); + * + * support.popContext(); + * </pre> + * + * <p>Note that this class is optimized for the use case where most + * elements do not contain Namespace declarations: if the same + * prefix/URI mapping is repeated for each context (for example), this + * class will be somewhat less efficient.</p> + * + * <p>Although SAX drivers (parsers) may choose to use this class to + * implement namespace handling, they are not required to do so. + * Applications must track namespace information themselves if they + * want to use namespace information. + * + * @since SAX 2.0 + * @author David Megginson + * @version 2.0.1 (sax2r2) + */ +public class NamespaceSupport +{ + + + //////////////////////////////////////////////////////////////////// + // Constants. + //////////////////////////////////////////////////////////////////// + + + /** + * The XML Namespace URI as a constant. + * The value is <code>http://www.w3.org/XML/1998/namespace</code> + * as defined in the XML Namespaces specification. + * + * <p>This is the Namespace URI that is automatically mapped + * to the "xml" prefix.</p> + */ + public final static String XMLNS = + "http://www.w3.org/XML/1998/namespace"; + + + /** + * An empty enumeration. + */ + private final static Enumeration EMPTY_ENUMERATION = + new Vector().elements(); + + + //////////////////////////////////////////////////////////////////// + // Constructor. + //////////////////////////////////////////////////////////////////// + + + /** + * Create a new Namespace support object. + */ + public NamespaceSupport () + { + reset(); + } + + + + //////////////////////////////////////////////////////////////////// + // Context management. + //////////////////////////////////////////////////////////////////// + + + /** + * Reset this Namespace support object for reuse. + * + * <p>It is necessary to invoke this method before reusing the + * Namespace support object for a new session.</p> + */ + public void reset () + { + contexts = new Context[32]; + contextPos = 0; + contexts[contextPos] = currentContext = new Context(); + currentContext.declarePrefix("xml", XMLNS); + } + + + /** + * Start a new Namespace context. + * The new context will automatically inherit + * the declarations of its parent context, but it will also keep + * track of which declarations were made within this context. + * + * <p>Event callback code should start a new context once per element. + * This means being ready to call this in either of two places. + * For elements that don't include namespace declarations, the + * <em>ContentHandler.startElement()</em> callback is the right place. + * For elements with such a declaration, it'd done in the first + * <em>ContentHandler.startPrefixMapping()</em> callback. + * A boolean flag can be used to + * track whether a context has been started yet. When either of + * those methods is called, it checks the flag to see if a new context + * needs to be started. If so, it starts the context and sets the + * flag. After <em>ContentHandler.startElement()</em> + * does that, it always clears the flag. + * + * <p>Normally, SAX drivers would push a new context at the beginning + * of each XML element. Then they perform a first pass over the + * attributes to process all namespace declarations, making + * <em>ContentHandler.startPrefixMapping()</em> callbacks. + * Then a second pass is made, to determine the namespace-qualified + * names for all attributes and for the element name. + * Finally all the information for the + * <em>ContentHandler.startElement()</em> callback is available, + * so it can then be made. + * + * <p>The Namespace support object always starts with a base context + * already in force: in this context, only the "xml" prefix is + * declared.</p> + * + * @see org.xml.sax.ContentHandler + * @see #popContext + */ + public void pushContext () + { + int max = contexts.length; + + contexts [contextPos].declsOK = false; + contextPos++; + + // Extend the array if necessary + if (contextPos >= max) { + Context newContexts[] = new Context[max*2]; + System.arraycopy(contexts, 0, newContexts, 0, max); + max *= 2; + contexts = newContexts; + } + + // Allocate the context if necessary. + currentContext = contexts[contextPos]; + if (currentContext == null) { + contexts[contextPos] = currentContext = new Context(); + } + + // Set the parent, if any. + if (contextPos > 0) { + currentContext.setParent(contexts[contextPos - 1]); + } + } + + + /** + * Revert to the previous Namespace context. + * + * <p>Normally, you should pop the context at the end of each + * XML element. After popping the context, all Namespace prefix + * mappings that were previously in force are restored.</p> + * + * <p>You must not attempt to declare additional Namespace + * prefixes after popping a context, unless you push another + * context first.</p> + * + * @see #pushContext + */ + public void popContext () + { + contexts[contextPos].clear(); + contextPos--; + if (contextPos < 0) { + throw new EmptyStackException(); + } + currentContext = contexts[contextPos]; + } + + + + //////////////////////////////////////////////////////////////////// + // Operations within a context. + //////////////////////////////////////////////////////////////////// + + + /** + * Declare a Namespace prefix. All prefixes must be declared + * before they are referenced. For example, a SAX driver (parser) + * would scan an element's attributes + * in two passes: first for namespace declarations, + * then a second pass using {@link #processName processName()} to + * interpret prefixes against (potentially redefined) prefixes. + * + * <p>This method declares a prefix in the current Namespace + * context; the prefix will remain in force until this context + * is popped, unless it is shadowed in a descendant context.</p> + * + * <p>To declare the default element Namespace, use the empty string as + * the prefix.</p> + * + * <p>Note that you must <em>not</em> declare a prefix after + * you've pushed and popped another Namespace context, or + * treated the declarations phase as complete by processing + * a prefixed name.</p> + * + * <p>Note that there is an asymmetry in this library: {@link + * #getPrefix getPrefix} will not return the "" prefix, + * even if you have declared a default element namespace. + * To check for a default namespace, + * you have to look it up explicitly using {@link #getURI getURI}. + * This asymmetry exists to make it easier to look up prefixes + * for attribute names, where the default prefix is not allowed.</p> + * + * @param prefix The prefix to declare, or the empty string to + * indicate the default element namespace. This may never have + * the value "xml" or "xmlns". + * @param uri The Namespace URI to associate with the prefix. + * @return true if the prefix was legal, false otherwise + * @exception IllegalStateException when a prefix is declared + * after looking up a name in the context, or after pushing + * another context on top of it. + * + * @see #processName + * @see #getURI + * @see #getPrefix + */ + public boolean declarePrefix (String prefix, String uri) + { + if (prefix.equals("xml") || prefix.equals("xmlns")) { + return false; + } else { + currentContext.declarePrefix(prefix, uri); + return true; + } + } + + + /** + * Process a raw XML 1.0 name, after all declarations in the current + * context have been handled by {@link #declarePrefix declarePrefix()}. + * + * <p>This method processes a raw XML 1.0 name in the current + * context by removing the prefix and looking it up among the + * prefixes currently declared. The return value will be the + * array supplied by the caller, filled in as follows:</p> + * + * <dl> + * <dt>parts[0]</dt> + * <dd>The Namespace URI, or an empty string if none is + * in use.</dd> + * <dt>parts[1]</dt> + * <dd>The local name (without prefix).</dd> + * <dt>parts[2]</dt> + * <dd>The original raw name.</dd> + * </dl> + * + * <p>All of the strings in the array will be internalized. If + * the raw name has a prefix that has not been declared, then + * the return value will be null.</p> + * + * <p>Note that attribute names are processed differently than + * element names: an unprefixed element name will received the + * default Namespace (if any), while an unprefixed attribute name + * will not.</p> + * + * @param qName The raw XML 1.0 name to be processed. + * @param parts An array supplied by the caller, capable of + * holding at least three members. + * @param isAttribute A flag indicating whether this is an + * attribute name (true) or an element name (false). + * @return The supplied array holding three internalized strings + * representing the Namespace URI (or empty string), the + * local name, and the raw XML 1.0 name; or null if there + * is an undeclared prefix. + * @see #declarePrefix + * @see java.lang.String#intern */ + public String [] processName (String qName, String parts[], + boolean isAttribute) + { + String myParts[] = currentContext.processName(qName, isAttribute); + if (myParts == null) { + return null; + } else { + parts[0] = myParts[0]; + parts[1] = myParts[1]; + parts[2] = myParts[2]; + return parts; + } + } + + + /** + * Look up a prefix and get the currently-mapped Namespace URI. + * + * <p>This method looks up the prefix in the current context. + * Use the empty string ("") for the default Namespace.</p> + * + * @param prefix The prefix to look up. + * @return The associated Namespace URI, or null if the prefix + * is undeclared in this context. + * @see #getPrefix + * @see #getPrefixes + */ + public String getURI (String prefix) + { + return currentContext.getURI(prefix); + } + + + /** + * Return an enumeration of all prefixes currently declared. + * + * <p><strong>Note:</strong> if there is a default prefix, it will not be + * returned in this enumeration; check for the default prefix + * using the {@link #getURI getURI} with an argument of "".</p> + * + * @return An enumeration of all prefixes declared in the + * current context except for the empty (default) + * prefix. + * @see #getDeclaredPrefixes + * @see #getURI + */ + public Enumeration getPrefixes () + { + return currentContext.getPrefixes(); + } + + + /** + * Return one of the prefixes mapped to a Namespace URI. + * + * <p>If more than one prefix is currently mapped to the same + * URI, this method will make an arbitrary selection; if you + * want all of the prefixes, use the {@link #getPrefixes} + * method instead.</p> + * + * <p><strong>Note:</strong> this will never return the empty (default) prefix; + * to check for a default prefix, use the {@link #getURI getURI} + * method with an argument of "".</p> + * + * @param uri The Namespace URI. + * @param isAttribute true if this prefix is for an attribute + * (and the default Namespace is not allowed). + * @return One of the prefixes currently mapped to the URI supplied, + * or null if none is mapped or if the URI is assigned to + * the default Namespace. + * @see #getPrefixes(java.lang.String) + * @see #getURI + */ + public String getPrefix (String uri) + { + return currentContext.getPrefix(uri); + } + + + /** + * Return an enumeration of all prefixes currently declared for a URI. + * + * <p>This method returns prefixes mapped to a specific Namespace + * URI. The xml: prefix will be included. If you want only one + * prefix that's mapped to the Namespace URI, and you don't care + * which one you get, use the {@link #getPrefix getPrefix} + * method instead.</p> + * + * <p><strong>Note:</strong> the empty (default) prefix is <em>never</em> included + * in this enumeration; to check for the presence of a default + * Namespace, use the {@link #getURI getURI} method with an + * argument of "".</p> + * + * @param uri The Namespace URI. + * @return An enumeration of all prefixes declared in the + * current context. + * @see #getPrefix + * @see #getDeclaredPrefixes + * @see #getURI + */ + public Enumeration getPrefixes (String uri) + { + Vector prefixes = new Vector(); + Enumeration allPrefixes = getPrefixes(); + while (allPrefixes.hasMoreElements()) { + String prefix = (String)allPrefixes.nextElement(); + if (uri.equals(getURI(prefix))) { + prefixes.addElement(prefix); + } + } + return prefixes.elements(); + } + + + /** + * Return an enumeration of all prefixes declared in this context. + * + * <p>The empty (default) prefix will be included in this + * enumeration; note that this behaviour differs from that of + * {@link #getPrefix} and {@link #getPrefixes}.</p> + * + * @return An enumeration of all prefixes declared in this + * context. + * @see #getPrefixes + * @see #getURI + */ + public Enumeration getDeclaredPrefixes () + { + return currentContext.getDeclaredPrefixes(); + } + + + + //////////////////////////////////////////////////////////////////// + // Internal state. + //////////////////////////////////////////////////////////////////// + + private Context contexts[]; + private Context currentContext; + private int contextPos; + + + + //////////////////////////////////////////////////////////////////// + // Internal classes. + //////////////////////////////////////////////////////////////////// + + /** + * Internal class for a single Namespace context. + * + * <p>This module caches and reuses Namespace contexts, + * so the number allocated + * will be equal to the element depth of the document, not to the total + * number of elements (i.e. 5-10 rather than tens of thousands). + * Also, data structures used to represent contexts are shared when + * possible (child contexts without declarations) to further reduce + * the amount of memory that's consumed. + * </p> + */ + final class Context { + + /** + * Create the root-level Namespace context. + */ + Context () + { + copyTables(); + } + + + /** + * (Re)set the parent of this Namespace context. + * The context must either have been freshly constructed, + * or must have been cleared. + * + * @param context The parent Namespace context object. + */ + void setParent (Context parent) + { + this.parent = parent; + declarations = null; + prefixTable = parent.prefixTable; + uriTable = parent.uriTable; + elementNameTable = parent.elementNameTable; + attributeNameTable = parent.attributeNameTable; + defaultNS = parent.defaultNS; + declSeen = false; + declsOK = true; + } + + /** + * Makes associated state become collectible, + * invalidating this context. + * {@link #setParent} must be called before + * this context may be used again. + */ + void clear () + { + parent = null; + prefixTable = null; + uriTable = null; + elementNameTable = null; + attributeNameTable = null; + defaultNS = null; + } + + + /** + * Declare a Namespace prefix for this context. + * + * @param prefix The prefix to declare. + * @param uri The associated Namespace URI. + * @see org.xml.sax.helpers.NamespaceSupport#declarePrefix + */ + void declarePrefix (String prefix, String uri) + { + // Lazy processing... + if (!declsOK) + throw new IllegalStateException ( + "can't declare any more prefixes in this context"); + if (!declSeen) { + copyTables(); + } + if (declarations == null) { + declarations = new Vector(); + } + + prefix = prefix.intern(); + uri = uri.intern(); + if ("".equals(prefix)) { + if ("".equals(uri)) { + defaultNS = null; + } else { + defaultNS = uri; + } + } else { + prefixTable.put(prefix, uri); + uriTable.put(uri, prefix); // may wipe out another prefix + } + declarations.addElement(prefix); + } + + + /** + * Process a raw XML 1.0 name in this context. + * + * @param qName The raw XML 1.0 name. + * @param isAttribute true if this is an attribute name. + * @return An array of three strings containing the + * URI part (or empty string), the local part, + * and the raw name, all internalized, or null + * if there is an undeclared prefix. + * @see org.xml.sax.helpers.NamespaceSupport#processName + */ + String [] processName (String qName, boolean isAttribute) + { + String name[]; + Hashtable table; + + // detect errors in call sequence + declsOK = false; + + // Select the appropriate table. + if (isAttribute) { + table = attributeNameTable; + } else { + table = elementNameTable; + } + + // Start by looking in the cache, and + // return immediately if the name + // is already known in this content + name = (String[])table.get(qName); + if (name != null) { + return name; + } + + // We haven't seen this name in this + // context before. Maybe in the parent + // context, but we can't assume prefix + // bindings are the same. + name = new String[3]; + name[2] = qName.intern(); + int index = qName.indexOf(':'); + + + // No prefix. + if (index == -1) { + if (isAttribute || defaultNS == null) { + name[0] = ""; + } else { + name[0] = defaultNS; + } + name[1] = name[2]; + } + + // Prefix + else { + String prefix = qName.substring(0, index); + String local = qName.substring(index+1); + String uri; + if ("".equals(prefix)) { + uri = defaultNS; + } else { + uri = (String)prefixTable.get(prefix); + } + if (uri == null) { + return null; + } + name[0] = uri; + name[1] = local.intern(); + } + + // Save in the cache for future use. + // (Could be shared with parent context...) + table.put(name[2], name); + return name; + } + + + /** + * Look up the URI associated with a prefix in this context. + * + * @param prefix The prefix to look up. + * @return The associated Namespace URI, or null if none is + * declared. + * @see org.xml.sax.helpers.NamespaceSupport#getURI + */ + String getURI (String prefix) + { + if ("".equals(prefix)) { + return defaultNS; + } else if (prefixTable == null) { + return null; + } else { + return (String)prefixTable.get(prefix); + } + } + + + /** + * Look up one of the prefixes associated with a URI in this context. + * + * <p>Since many prefixes may be mapped to the same URI, + * the return value may be unreliable.</p> + * + * @param uri The URI to look up. + * @return The associated prefix, or null if none is declared. + * @see org.xml.sax.helpers.NamespaceSupport#getPrefix + */ + String getPrefix (String uri) + { + if (uriTable == null) { + return null; + } else { + return (String)uriTable.get(uri); + } + } + + + /** + * Return an enumeration of prefixes declared in this context. + * + * @return An enumeration of prefixes (possibly empty). + * @see org.xml.sax.helpers.NamespaceSupport#getDeclaredPrefixes + */ + Enumeration getDeclaredPrefixes () + { + if (declarations == null) { + return EMPTY_ENUMERATION; + } else { + return declarations.elements(); + } + } + + + /** + * Return an enumeration of all prefixes currently in force. + * + * <p>The default prefix, if in force, is <em>not</em> + * returned, and will have to be checked for separately.</p> + * + * @return An enumeration of prefixes (never empty). + * @see org.xml.sax.helpers.NamespaceSupport#getPrefixes + */ + Enumeration getPrefixes () + { + if (prefixTable == null) { + return EMPTY_ENUMERATION; + } else { + return prefixTable.keys(); + } + } + + + + //////////////////////////////////////////////////////////////// + // Internal methods. + //////////////////////////////////////////////////////////////// + + + /** + * Copy on write for the internal tables in this context. + * + * <p>This class is optimized for the normal case where most + * elements do not contain Namespace declarations.</p> + */ + private void copyTables () + { + if (prefixTable != null) { + prefixTable = (Hashtable)prefixTable.clone(); + } else { + prefixTable = new Hashtable(); + } + if (uriTable != null) { + uriTable = (Hashtable)uriTable.clone(); + } else { + uriTable = new Hashtable(); + } + elementNameTable = new Hashtable(); + attributeNameTable = new Hashtable(); + declSeen = true; + } + + + + //////////////////////////////////////////////////////////////// + // Protected state. + //////////////////////////////////////////////////////////////// + + Hashtable prefixTable; + Hashtable uriTable; + Hashtable elementNameTable; + Hashtable attributeNameTable; + String defaultNS = null; + boolean declsOK = true; + + + + //////////////////////////////////////////////////////////////// + // Internal state. + //////////////////////////////////////////////////////////////// + + private Vector declarations = null; + private boolean declSeen = false; + private Context parent = null; + } +} + +// end of NamespaceSupport.java |