+++ /dev/null
-// 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 1.15 2004/04/26 17:34:35 dmegginson 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 names into their Namespace
- * parts; it can also be used in reverse for generating XML qnames
- * 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
-{
-
-\f
- ////////////////////////////////////////////////////////////////////
- // Constants.
- ////////////////////////////////////////////////////////////////////
-
-
- /**
- * The XML Namespace URI as a constant.
- * The value is <code>http://www.w3.org/XML/1998/namespace</code>
- * as defined in the "Namespaces in XML" * recommendation.
- *
- * <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";
-
-
- /**
- * The namespace declaration URI as a constant.
- * The value is <code>http://www.w3.org/xmlns/2000/</code>, as defined
- * in a backwards-incompatible erratum to the "Namespaces in XML"
- * recommendation. Because that erratum postdated SAX2, SAX2 defaults
- * to the original recommendation, and does not normally use this URI.
- *
- *
- * <p>This is the Namespace URI that is optionally applied to
- * <em>xmlns</em> and <em>xmlns:*</em> attributes, which are used to
- * declare namespaces. </p>
- *
- * @since SAX 2.1alpha
- * @see #setNamespaceDeclUris
- * @see #isNamespaceDeclUris
- */
- public final static String NSDECL =
- "http://www.w3.org/xmlns/2000/";
-
-
- /**
- * An empty enumeration.
- */
- private final static Enumeration EMPTY_ENUMERATION =
- new Vector().elements();
-
-\f
- ////////////////////////////////////////////////////////////////////
- // Constructor.
- ////////////////////////////////////////////////////////////////////
-
-
- /**
- * Create a new Namespace support object.
- */
- public NamespaceSupport ()
- {
- reset();
- }
-
-
-\f
- ////////////////////////////////////////////////////////////////////
- // 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. If namespace
- * declaration URIs are to be supported, that flag must also
- * be set to a non-default value.
- * </p>
- *
- * @see #setNamespaceDeclUris
- */
- public void reset ()
- {
- contexts = new Context[32];
- namespaceDeclUris = false;
- 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];
- }
-
-
-\f
- ////////////////////////////////////////////////////////////////////
- // 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
- *
- * @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 qualified name, after all declarations in the
- * current context have been handled by {@link #declarePrefix
- * declarePrefix()}.
- *
- * <p>This method processes a raw XML qualified 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 receive the
- * default Namespace (if any), while an unprefixed attribute name
- * will not.</p>
- *
- * @param qName The XML qualified 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 XML qualified 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 whose declarations are
- * active in the current context.
- * This includes declarations from parent contexts that have
- * not been overridden.
- *
- * <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 prefixes (never empty).
- * @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
- * @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 for a given URI whose
- * declarations are active in the current context.
- * This includes declarations from parent contexts that have
- * not been overridden.
- *
- * <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 prefixes (never empty).
- * @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();
- }
-
- /**
- * Controls whether namespace declaration attributes are placed
- * into the {@link #NSDECL NSDECL} namespace
- * by {@link #processName processName()}. This may only be
- * changed before any contexts have been pushed.
- *
- * @since SAX 2.1alpha
- *
- * @exception IllegalStateException when attempting to set this
- * after any context has been pushed.
- */
- public void setNamespaceDeclUris (boolean value)
- {
- if (contextPos != 0)
- throw new IllegalStateException ();
- if (value == namespaceDeclUris)
- return;
- namespaceDeclUris = value;
- if (value)
- currentContext.declarePrefix ("xmlns", NSDECL);
- else {
- contexts[contextPos] = currentContext = new Context();
- currentContext.declarePrefix("xml", XMLNS);
- }
- }
-
- /**
- * Returns true if namespace declaration attributes are placed into
- * a namespace. This behavior is not the default.
- *
- * @since SAX 2.1alpha
- */
- public boolean isNamespaceDeclUris ()
- { return namespaceDeclUris; }
-
-
-\f
- ////////////////////////////////////////////////////////////////////
- // Internal state.
- ////////////////////////////////////////////////////////////////////
-
- private Context contexts[];
- private Context currentContext;
- private int contextPos;
- private boolean namespaceDeclUris;
-
-\f
- ////////////////////////////////////////////////////////////////////
- // 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 an XML qualified name in this context.
- *
- * @param qName The XML qualified 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) {
- if (qName == "xmlns" && namespaceDeclUris)
- name[0] = NSDECL;
- else
- name[0] = "";
- } else if (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
- || (!isAttribute && "xmlns".equals (prefix))) {
- 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();
- }
- }
-
-
-\f
- ////////////////////////////////////////////////////////////////
- // 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;
- }
-
-
-\f
- ////////////////////////////////////////////////////////////////
- // Protected state.
- ////////////////////////////////////////////////////////////////
-
- Hashtable prefixTable;
- Hashtable uriTable;
- Hashtable elementNameTable;
- Hashtable attributeNameTable;
- String defaultNS = null;
- boolean declsOK = true;
-
-
-\f
- ////////////////////////////////////////////////////////////////
- // Internal state.
- ////////////////////////////////////////////////////////////////
-
- private Vector declarations = null;
- private boolean declSeen = false;
- private Context parent = null;
- }
-}
-
-// end of NamespaceSupport.java
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