http://xml.apache.org/xalan-j/: Serializer to write out XML, HTML etc. as a stream of characters from an input DOM or from input SAX events. (The Apache Software Foundation) 
/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the  "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/*
 * $Id: NamespaceSupport2.java 468655 2006-10-28 07:12:06Z minchau $
 */
package org.apache.xml.utils;

import java.util.EmptyStackException;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Vector;


Encapsulate Namespace tracking logic for use by SAX drivers.

This class is an attempt to rewrite the SAX NamespaceSupport
"helper" class for improved efficiency. It can be used to track the
namespace declarations currently in scope, providing lookup
routines to map prefixes to URIs and vice versa.


ISSUE: For testing purposes, I've extended NamespaceSupport even
though I'm completely reasserting all behaviors and fields.
Wasteful.... But SAX did not put an interface under that object and
we seem to have written that SAX class into our APIs... and I don't
want to argue with it right now. 


See Also:
  • NamespaceSupport
/**
 * Encapsulate Namespace tracking logic for use by SAX drivers.
 *
 * <p>This class is an attempt to rewrite the SAX NamespaceSupport
 * "helper" class for improved efficiency. It can be used to track the
 * namespace declarations currently in scope, providing lookup
 * routines to map prefixes to URIs and vice versa.</p>
 *
 * <p>ISSUE: For testing purposes, I've extended NamespaceSupport even
 * though I'm completely reasserting all behaviors and fields.
 * Wasteful.... But SAX did not put an interface under that object and
 * we seem to have written that SAX class into our APIs... and I don't
 * want to argue with it right now. </p>
 *
 * @see org.xml.sax.helpers.NamespaceSupport
 * */
public class NamespaceSupport2
    extends org.xml.sax.helpers.NamespaceSupport
{
    ////////////////////////////////////////////////////////////////////
    // Internal state.
    ////////////////////////////////////////////////////////////////////

    private Context2 currentContext; // Current point on the double-linked stack


    ////////////////////////////////////////////////////////////////////
    // Constants.
    ////////////////////////////////////////////////////////////////////


    
The XML Namespace as a constant.

This is the Namespace URI that is automatically mapped
to the "xml" prefix.


/**
     * 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";


    ////////////////////////////////////////////////////////////////////
    // Constructor.
    ////////////////////////////////////////////////////////////////////


    
Create a new Namespace support object.

/**
     * Create a new Namespace support object.
     */
    public NamespaceSupport2 ()
    {
        reset();
    }


    ////////////////////////////////////////////////////////////////////
    // Context management.
    ////////////////////////////////////////////////////////////////////


    
Reset this Namespace support object for reuse.

It is necessary to invoke this method before reusing the
Namespace support object for a new session.


/**
     * 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 ()
    {
        // Discarding the whole stack doesn't save us a lot versus
        // creating a new NamespaceSupport. Do we care, or should we
        // change this to just reset the root context?
        currentContext = new Context2(null);
        currentContext.declarePrefix("xml", XMLNS);
    }


    
Start a new Namespace context.

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.


The Namespace support object always starts with a base context
already in force: in this context, only the "xml" prefix is
declared.


See Also:
  • popContext
/**
     * 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 ()
    {
        // JJK: Context has a parent pointer.
        // That means we don't need a stack to pop.
        // We may want to retain for reuse, but that can be done via
        // a child pointer.

        Context2 parentContext=currentContext;
        currentContext = parentContext.getChild();
        if (currentContext == null){
                currentContext = new Context2(parentContext);
            }
        else{
            // JJK: This will wipe out any leftover data
            // if we're reusing a previously allocated Context.
            currentContext.setParent(parentContext);
        }
    }


    
Revert to the previous Namespace context.

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.


You must not attempt to declare additional Namespace
prefixes after popping a context, unless you push another
context first.


See Also:
  • pushContext
/**
     * 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 ()
    {
        Context2 parentContext=currentContext.getParent();
        if(parentContext==null)
            throw new EmptyStackException();
        else
            currentContext = parentContext;
    }



    ////////////////////////////////////////////////////////////////////
    // Operations within a context.
    ////////////////////////////////////////////////////////////////////


    
Declare a Namespace prefix.

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.


To declare a default Namespace, use the empty string.  The
prefix must not be "xml" or "xmlns".


Note that you must not declare a prefix after
you've pushed and popped another Namespace.


Note that there is an asymmetry in this library: while 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 getURI. This asymmetry exists to make it easier to look up prefixes for attribute names, where the default prefix is not allowed.


Params:
  • prefix – The prefix to declare, or null for the empty
       string.
  • uri – The Namespace URI to associate with the prefix.
See Also:
Returns:true if the prefix was legal, false otherwise
/**
     * 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.

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:




parts[0]


The Namespace URI, or an empty string if none is
 in use.


parts[1]


The local name (without prefix).


parts[2]


The original raw name.




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.


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.


Params:
  • qName – The raw XML 1.0 name to be processed.
  • parts – A string array supplied by the caller, capable of
       holding at least three members.
  • isAttribute – A flag indicating whether this is an
       attribute name (true) or an element name (false).
See Also:
Returns: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.
/**
     * 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 A string 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[] name=currentContext.processName(qName, isAttribute);
        if(name==null)
            return null;

        // JJK: This recopying is required because processName may return
        // a cached result. I Don't Like It. *****
        System.arraycopy(name,0,parts,0,3);
        return parts;
    }


    
Look up a prefix and get the currently-mapped Namespace URI.

This method looks up the prefix in the current context.
Use the empty string ("") for the default Namespace.


Params:
  • prefix – The prefix to look up.
See Also:
Returns:The associated Namespace URI, or null if the prefix
        is undeclared in this context.
/**
     * 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.

Note: if there is a default prefix, it will not be returned in this enumeration; check for the default prefix using the getURI with an argument of "".


See Also:
Returns:An enumeration of all prefixes declared in the
        current context except for the empty (default)
        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.

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 getPrefixes method instead.


Note: this will never return the empty (default) prefix; to check for a default prefix, use the getURI method with an argument of "".


Params:
  • uri – The Namespace URI.
See Also:
Returns: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.
/**
     * 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 currently declared for a URI.

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 getPrefix method instead.


Note: the empty (default) prefix is
never included in this enumeration; to check for the presence of a default Namespace, use the getURI method with an argument of "".


Params:
  • uri – The Namespace URI.
See Also:
Returns:An enumeration of all prefixes declared in the
        current context.
/**
     * 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)
    {
        // JJK: The old code involved creating a vector, filling it
        // with all the matching prefixes, and then getting its
        // elements enumerator. Wastes storage, wastes cycles if we
        // don't actually need them all. Better to either implement
        // a specific enumerator for these prefixes... or a filter
        // around the all-prefixes enumerator, which comes out to
        // roughly the same thing.
        //
        // **** Currently a filter. That may not be most efficient
        // when I'm done restructuring storage!
        return new PrefixForUriEnumerator(this,uri,getPrefixes());       
    }
    

    
Return an enumeration of all prefixes declared in this context.

The empty (default) prefix will be included in this enumeration; note that this behaviour differs from that of getPrefix and getPrefixes.


See Also:
Returns:An enumeration of all prefixes declared in this
        context.
/**
     * 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();
    }



}

////////////////////////////////////////////////////////////////////
// Local classes.
// These were _internal_ classes... but in fact they don't have to be,
// and may be more efficient if they aren't. 
////////////////////////////////////////////////////////////////////


Implementation of Enumeration filter, wrapped
aroung the get-all-prefixes version of the operation. This is NOT
necessarily the most efficient approach; finding the URI and then asking
what prefixes apply to it might make much more sense.

/**
 * Implementation of Enumeration filter, wrapped
 * aroung the get-all-prefixes version of the operation. This is NOT
 * necessarily the most efficient approach; finding the URI and then asking
 * what prefixes apply to it might make much more sense.
 */
class PrefixForUriEnumerator implements Enumeration
{
    private Enumeration allPrefixes;
    private String uri;
    private String lookahead=null;
    private NamespaceSupport2 nsup;
     
    // Kluge: Since one can't do a constructor on an
    // anonymous class (as far as I know)...
    PrefixForUriEnumerator(NamespaceSupport2 nsup,String uri, Enumeration allPrefixes)
    {
	this.nsup=nsup;
        this.uri=uri;
        this.allPrefixes=allPrefixes;
    }
        
    public boolean hasMoreElements()
    {
        if(lookahead!=null)
            return true;
            
        while(allPrefixes.hasMoreElements())
            {
                String prefix=(String)allPrefixes.nextElement();
                if(uri.equals(nsup.getURI(prefix)))
                    {
                        lookahead=prefix;
                        return true;
                    }
            }
        return false;
    }
        
    public Object nextElement()
    {
        if(hasMoreElements())
            {
                String tmp=lookahead;
                lookahead=null;
                return tmp;
            }
        else
            throw new java.util.NoSuchElementException();
    }
}


Internal class for a single Namespace context.

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).


/**
 * 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 Context2 {

    ////////////////////////////////////////////////////////////////
    // Manefest Constants
    ////////////////////////////////////////////////////////////////
        
    
An empty enumeration.

/**
     * An empty enumeration.
     */
    private final static Enumeration EMPTY_ENUMERATION =
        new Vector().elements();

    ////////////////////////////////////////////////////////////////
    // Protected state.
    ////////////////////////////////////////////////////////////////
        
    Hashtable prefixTable;
    Hashtable uriTable;
    Hashtable elementNameTable;
    Hashtable attributeNameTable;
    String defaultNS = null;

    ////////////////////////////////////////////////////////////////
    // Internal state.
    ////////////////////////////////////////////////////////////////
        
    private Vector declarations = null;
    private boolean tablesDirty = false;
    private Context2 parent = null;
    private Context2 child = null;

    
Create a new Namespace context.

/**
     * Create a new Namespace context.
     */
    Context2 (Context2 parent)
    {
        if(parent==null)
            {
                prefixTable = new Hashtable();
                uriTable = new Hashtable();
                elementNameTable=null; 
                attributeNameTable=null; 
            }
        else
            setParent(parent);
    }

        
    
@returnsThe child Namespace context object, or null if this
is the last currently on the chain.
/**
     * @returns The child Namespace context object, or null if this
     * is the last currently on the chain.
     */
    Context2 getChild()
    {
        return child;
    }
        
    
@returnsThe parent Namespace context object, or null if this
is the root.
/**
     * @returns The parent Namespace context object, or null if this
     * is the root.
     */
    Context2 getParent()
    {
        return parent;
    }
        
    
(Re)set the parent of this Namespace context.
This is separate from the c'tor because it's re-applied
when a Context2 is reused by push-after-pop.

Params:
  • context – The parent Namespace context object.
/**
     * (Re)set the parent of this Namespace context.
     * This is separate from the c'tor because it's re-applied
     * when a Context2 is reused by push-after-pop.
     *
     * @param context The parent Namespace context object.
     */
    void setParent (Context2 parent)
    {
        this.parent = parent;
        parent.child = this;        // JJK: Doubly-linked
        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.

Params:
  • prefix – The prefix to declare.
  • uri – The associated Namespace URI.
See Also:
  • declarePrefix.declarePrefix
/**
     * Declare a Namespace prefix for this context.
     *
     * @param prefix The prefix to declare.
     * @param uri The associated Namespace URI.
     * @see org.xml.sax.helpers.NamespaceSupport2#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.

Params:
  • qName – The raw XML 1.0 name.
  • isAttribute – true if this is an attribute name.
See Also:
  • processName.processName
Returns: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.
/**
     * 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.NamespaceSupport2#processName
     */
    String [] processName (String qName, boolean isAttribute)
    {
        String name[];
        Hashtable table;
            
                                // Select the appropriate table.
        if (isAttribute) {
            if(elementNameTable==null)
                elementNameTable=new Hashtable();
            table = elementNameTable;
        } else {
            if(attributeNameTable==null)
                attributeNameTable=new Hashtable();
            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.

Params:
  • prefix – The prefix to look up.
See Also:
  • getURI.getURI
Returns:The associated Namespace URI, or null if none is
        declared.
/**
     * 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.NamespaceSupport2#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.

Since many prefixes may be mapped to the same URI,
the return value may be unreliable.


Params:
  • uri – The URI to look up.
See Also:
  • getPrefix.getPrefix
Returns:The associated prefix, or null if none is declared.
/**
     * 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.NamespaceSupport2#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.

See Also:
  • getDeclaredPrefixes.getDeclaredPrefixes
Returns:An enumeration of prefixes (possibly empty).
/**
     * Return an enumeration of prefixes declared in this context.
     *
     * @return An enumeration of prefixes (possibly empty).
     * @see org.xml.sax.helpers.NamespaceSupport2#getDeclaredPrefixes
     */
    Enumeration getDeclaredPrefixes ()
    {
        if (declarations == null) {
            return EMPTY_ENUMERATION;
        } else {
            return declarations.elements();
        }
    }
        
        
    
Return an enumeration of all prefixes currently in force.

The default prefix, if in force, is not
returned, and will have to be checked for separately.


See Also:
  • getPrefixes.getPrefixes
Returns:An enumeration of prefixes (never empty).
/**
     * 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.NamespaceSupport2#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.

This class is optimized for the normal case where most
elements do not contain Namespace declarations. In that case,
the Context2 will share data structures with its parent.
New tables are obtained only when new declarations are issued,
so they can be popped off the stack.


 JJK: **** Alternative: each Context2 might declare
 _only_ its local bindings, and delegate upward if not found.


/**
     * 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. In that case,
     * the Context2 will share data structures with its parent.
     * New tables are obtained only when new declarations are issued,
     * so they can be popped off the stack.</p>
     *
     * <p> JJK: **** Alternative: each Context2 might declare
     *  _only_ its local bindings, and delegate upward if not found.</p>
     */     
    private void copyTables ()
    {
        // Start by copying our parent's bindings
        prefixTable = (Hashtable)prefixTable.clone();
        uriTable = (Hashtable)uriTable.clone();

        // Replace the caches with empty ones, rather than
        // trying to determine which bindings should be flushed.
        // As far as I can tell, these caches are never actually
        // used in Xalan... More efficient to remove the whole
        // cache system? ****
        if(elementNameTable!=null)
            elementNameTable=new Hashtable(); 
        if(attributeNameTable!=null)
            attributeNameTable=new Hashtable(); 
        tablesDirty = true;
    }

}


// end of NamespaceSupport2.java