namespacesupport.java

gcc的组建

    }


    /**
     * 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; }



    ////////////////////////////////////////////////////////////////////
    // Internal state.
    ////////////////////////////////////////////////////////////////////

    private Context contexts[];
    private Context currentContext;
    private int contextPos;
    private boolean namespaceDeclUris;


    ////////////////////////////////////////////////////////////////////
    // 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();
	    }
	}
	
	

	////////////////////////////////////////////////////////////////
	// 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