/*******************************************************************************
 * Copyright (c) 2008 Standards for Technology in Automotive Retail
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     David Carver - STAR - bug 224197 - initial API and implementation
 *                    based on work from Apache Xalan 2.7.0
 *******************************************************************************/
/*
 * Copyright 1999-2004 The Apache Software Foundation.
 *
 * Licensed 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: ElemTemplateElement.java,v 1.3 2008/03/28 02:38:15 dacarver Exp $
 */
package org.eclipse.wst.xsl.core.internal.compiler.xslt10.templates;

import java.io.Serializable;
import java.util.Enumeration;
import java.util.Vector;

import javax.xml.transform.SourceLocator;
import javax.xml.transform.TransformerException;

import org.eclipse.wst.xsl.core.compiler.xslt10.res.Messages;
import org.eclipse.wst.xsl.core.compiler.xslt10.res.XSLTErrorResources;
import org.eclipse.wst.xsl.core.internal.compiler.xslt10.transformer.TransformerImpl;
import org.apache.xml.serializer.SerializationHandler;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xml.utils.UnImplNode;
import org.apache.xpath.ExpressionNode;
import org.apache.xpath.WhitespaceStrippingElementMatcher;

import org.w3c.dom.DOMException;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import org.xml.sax.helpers.NamespaceSupport;

/**
 * An instance of this class represents an element inside an xsl:template class.
 * It has a single "execute" method which is expected to perform the given
 * action on the result tree. This class acts like a Element node, and
 * implements the Element interface, but is not a full implementation of that
 * interface... it only implements enough for basic traversal of the tree.
 * 
 * @see Stylesheet
 * @xsl.usage advanced
 */
public class ElemTemplateElement extends UnImplNode implements PrefixResolver,
		Serializable, ExpressionNode, WhitespaceStrippingElementMatcher,
		XSLTVisitable {
	static final long serialVersionUID = 4440018597841834447L;

	/**
	 * Construct a template element instance.
	 * 
	 */
	public ElemTemplateElement() {
	}

	/**
	 * Tell if this template is a compiled template.
	 * 
	 * @return Boolean flag indicating whether this is a compiled template
	 */
	public boolean isCompiledTemplate() {
		return false;
	}

	/**
	 * Get an integer representation of the element type.
	 * 
	 * @return An integer representation of the element, defined in the
	 *         Constants class.
	 * @see org.apache.xalan.templates.Constants
	 */
	public int getXSLToken() {
		return Constants.ELEMNAME_UNDEFINED;
	}

	/**
	 * Return the node name.
	 * 
	 * @return An invalid node name
	 */
	@Override
	public String getNodeName() {
		return "Unknown XSLT Element";
	}

	/**
	 * For now, just return the result of getNodeName(), which the local name.
	 * 
	 * @return The result of getNodeName().
	 */
	@Override
	public String getLocalName() {

		return getNodeName();
	}

	/**
	 * This function will be called on top-level elements only, just before the
	 * transform begins.
	 * 
	 * @param transformer
	 *            The XSLT TransformerFactory.
	 * 
	 * @throws TransformerException
	 */
	public void runtimeInit(TransformerImpl transformer)
			throws TransformerException {
	}

	/**
	 * Execute the element's primary function. Subclasses of this function may
	 * recursivly execute down the element tree.
	 * 
	 * @param transformer
	 *            The XSLT TransformerFactory.
	 * 
	 * @throws TransformerException
	 *             if any checked exception occurs.
	 */
	public void execute(TransformerImpl transformer)
			throws TransformerException {
	}

	/**
	 * Get the owning "composed" stylesheet. This looks up the inheritance chain
	 * until it calls getStylesheetComposed on a Stylesheet object, which will
	 * Get the owning aggregated stylesheet, or that stylesheet if it is
	 * aggregated.
	 * 
	 * @return the owning "composed" stylesheet.
	 */
	public StylesheetComposed getStylesheetComposed() {
		return m_parentNode.getStylesheetComposed();
	}

	/**
	 * Get the owning stylesheet. This looks up the inheritance chain until it
	 * calls getStylesheet on a Stylesheet object, which will return itself.
	 * 
	 * @return the owning stylesheet
	 */
	public Stylesheet getStylesheet() {
		return (null == m_parentNode) ? null : m_parentNode.getStylesheet();
	}

	/**
	 * Get the owning root stylesheet. This looks up the inheritance chain until
	 * it calls StylesheetRoot on a Stylesheet object, which will return a
	 * reference to the root stylesheet.
	 * 
	 * @return the owning root stylesheet
	 */
	public StylesheetRoot getStylesheetRoot() {
		return m_parentNode.getStylesheetRoot();
	}

	/**
	 * This function is called during recomposition to control how this element
	 * is composed.
	 */
	public void recompose(StylesheetRoot root) throws TransformerException {
	}

	/**
	 * This function is called after everything else has been recomposed, and
	 * allows the template to set remaining values that may be based on some
	 * other property that depends on recomposition.
	 */
	public void compose(StylesheetRoot sroot) throws TransformerException {
		resolvePrefixTables();
		ElemTemplateElement t = getFirstChildElem();
		m_hasTextLitOnly = ((t != null)
				&& (t.getXSLToken() == Constants.ELEMNAME_TEXTLITERALRESULT) && (t
				.getNextSiblingElem() == null));

		StylesheetRoot.ComposeState cstate = sroot.getComposeState();
		cstate.pushStackMark();
	}

	/**
	 * This after the template's children have been composed.
	 */
	public void endCompose(StylesheetRoot sroot) throws TransformerException {
		StylesheetRoot.ComposeState cstate = sroot.getComposeState();
		cstate.popStackMark();
	}

	/**
	 * Throw a template element runtime error. (Note: should we throw a
	 * TransformerException instead?)
	 * 
	 * @param msg
	 *            key of the error that occured.
	 * @param args
	 *            Arguments to be used in the message
	 */
	@Override
	public void error(String msg, Object[] args) {

		String themsg = Messages.createMessage(msg, args);

		throw new RuntimeException(Messages.createMessage(
				XSLTErrorResources.ER_ELEMTEMPLATEELEM_ERR,
				new Object[] { themsg }));
	}

	/*
	 * Throw an error.
	 * 
	 * @param msg Message key for the error
	 * 
	 */
	@Override
	public void error(String msg) {
		error(msg, null);
	}

	// Implemented DOM Element methods.
	/**
	 * Add a child to the child list. NOTE: This presumes the child did not
	 * previously have a parent. Making that assumption makes this a less
	 * expensive operation -- but requires that if you *do* want to reparent a
	 * node, you use removeChild() first to remove it from its previous context.
	 * Failing to do so will damage the tree.
	 * 
	 * @param newChild
	 *            Child to be added to child list
	 * 
	 * @return Child just added to the child list
	 * @throws DOMException
	 */
	@Override
	public Node appendChild(Node newChild) throws DOMException {

		if (null == newChild) {
			error(XSLTErrorResources.ER_NULL_CHILD, null); // "Trying to add a
															// null child!");
		}

		ElemTemplateElement elem = (ElemTemplateElement) newChild;

		if (null == m_firstChild) {
			m_firstChild = elem;
		} else {
			ElemTemplateElement last = (ElemTemplateElement) getLastChild();

			last.m_nextSibling = elem;
		}

		elem.m_parentNode = this;

		return newChild;
	}

	/**
	 * Add a child to the child list. NOTE: This presumes the child did not
	 * previously have a parent. Making that assumption makes this a less
	 * expensive operation -- but requires that if you *do* want to reparent a
	 * node, you use removeChild() first to remove it from its previous context.
	 * Failing to do so will damage the tree.
	 * 
	 * @param elem
	 *            Child to be added to child list
	 * 
	 * @return Child just added to the child list
	 */
	public ElemTemplateElement appendChild(ElemTemplateElement elem) {

		if (null == elem) {
			error(XSLTErrorResources.ER_NULL_CHILD, null); // "Trying to add a
															// null child!");
		}

		if (null == m_firstChild) {
			m_firstChild = elem;
		} else {
			ElemTemplateElement last = getLastChildElem();

			last.m_nextSibling = elem;
		}

		elem.setParentElem(this);

		return elem;
	}

	/**
	 * Tell if there are child nodes.
	 * 
	 * @return True if there are child nodes
	 */
	@Override
	public boolean hasChildNodes() {
		return (null != m_firstChild);
	}

	/**
	 * Get the type of the node.
	 * 
	 * @return Constant for this node type
	 */
	@Override
	public short getNodeType() {
		return org.w3c.dom.Node.ELEMENT_NODE;
	}

	/**
	 * Return the nodelist (same reference).
	 * 
	 * @return The nodelist containing the child nodes (this)
	 */
	@Override
	public NodeList getChildNodes() {
		return this;
	}

	/**
	 * Remove a child. ADDED 9/8/200 to support compilation. TODO: *****
	 * Alternative is "removeMe() from my parent if any" ... which is less well
	 * checked, but more convenient in some cases. Given that we assume only
	 * experts are calling this class, it might be preferable. It's less DOMish,
	 * though.
	 * 
	 * @param childETE
	 *            The child to remove. This operation is a no-op if oldChild is
	 *            not a child of this node.
	 * 
	 * @return the removed child, or null if the specified node was not a child
	 *         of this element.
	 */
	public ElemTemplateElement removeChild(ElemTemplateElement childETE) {

		if (childETE == null || childETE.m_parentNode != this)
			return null;

		// Pointers to the child
		if (childETE == m_firstChild)
			m_firstChild = childETE.m_nextSibling;
		else {
			ElemTemplateElement prev = childETE.getPreviousSiblingElem();

			prev.m_nextSibling = childETE.m_nextSibling;
		}

		// Pointers from the child
		childETE.m_parentNode = null;
		childETE.m_nextSibling = null;

		return childETE;
	}

	/**
	 * Replace the old child with a new child.
	 * 
	 * @param newChild
	 *            New child to replace with
	 * @param oldChild
	 *            Old child to be replaced
	 * 
	 * @return The new child
	 * 
	 * @throws DOMException
	 */
	@Override
	public Node replaceChild(Node newChild, Node oldChild) throws DOMException {

		if (oldChild == null || oldChild.getParentNode() != this)
			return null;

		ElemTemplateElement newChildElem = ((ElemTemplateElement) newChild);
		ElemTemplateElement oldChildElem = ((ElemTemplateElement) oldChild);

		// Fix up previous sibling.
		ElemTemplateElement prev = (ElemTemplateElement) oldChildElem
				.getPreviousSibling();

		if (null != prev)
			prev.m_nextSibling = newChildElem;

		// Fix up parent (this)
		if (m_firstChild == oldChildElem)
			m_firstChild = newChildElem;

		newChildElem.m_parentNode = this;
		oldChildElem.m_parentNode = null;
		newChildElem.m_nextSibling = oldChildElem.m_nextSibling;
		oldChildElem.m_nextSibling = null;

		// newChildElem.m_stylesheet = oldChildElem.m_stylesheet;
		// oldChildElem.m_stylesheet = null;
		return newChildElem;
	}

	/**
	 * Unimplemented. See org.w3c.dom.Node
	 * 
	 * @param newChild
	 *            New child node to insert
	 * @param refChild
	 *            Insert in front of this child
	 * 
	 * @return null
	 * 
	 * @throws DOMException
	 */
	@Override
	public Node insertBefore(Node newChild, Node refChild) throws DOMException {
		if (null == refChild) {
			appendChild(newChild);
			return newChild;
		}

		if (newChild == refChild) {
			// hmm...
			return newChild;
		}

		Node node = m_firstChild;
		Node prev = null;
		boolean foundit = false;

		while (null != node) {
			// If the newChild is already in the tree, it is first removed.
			if (newChild == node) {
				if (null != prev)
					((ElemTemplateElement) prev).m_nextSibling = (ElemTemplateElement) node
							.getNextSibling();
				else
					m_firstChild = (ElemTemplateElement) node.getNextSibling();
				node = node.getNextSibling();
				continue; // prev remains the same.
			}
			if (refChild == node) {
				if (null != prev) {
					((ElemTemplateElement) prev).m_nextSibling = (ElemTemplateElement) newChild;
				} else {
					m_firstChild = (ElemTemplateElement) newChild;
				}
				((ElemTemplateElement) newChild).m_nextSibling = (ElemTemplateElement) refChild;
				((ElemTemplateElement) newChild).setParentElem(this);
				prev = newChild;
				node = node.getNextSibling();
				foundit = true;
				continue;
			}
			prev = node;
			node = node.getNextSibling();
		}

		if (!foundit)
			throw new DOMException(DOMException.NOT_FOUND_ERR,
					"refChild was not found in insertBefore method!");
		else
			return newChild;
	}

	/**
	 * Replace the old child with a new child.
	 * 
	 * @param newChildElem
	 *            New child to replace with
	 * @param oldChildElem
	 *            Old child to be replaced
	 * 
	 * @return The new child
	 * 
	 * @throws DOMException
	 */
	public ElemTemplateElement replaceChild(ElemTemplateElement newChildElem,
			ElemTemplateElement oldChildElem) {

		if (oldChildElem == null || oldChildElem.getParentElem() != this)
			return null;

		// Fix up previous sibling.
		ElemTemplateElement prev = oldChildElem.getPreviousSiblingElem();

		if (null != prev)
			prev.m_nextSibling = newChildElem;

		// Fix up parent (this)
		if (m_firstChild == oldChildElem)
			m_firstChild = newChildElem;

		newChildElem.m_parentNode = this;
		oldChildElem.m_parentNode = null;
		newChildElem.m_nextSibling = oldChildElem.m_nextSibling;
		oldChildElem.m_nextSibling = null;

		// newChildElem.m_stylesheet = oldChildElem.m_stylesheet;
		// oldChildElem.m_stylesheet = null;
		return newChildElem;
	}

	/**
	 * NodeList method: Count the immediate children of this node
	 * 
	 * @return The count of children of this node
	 */
	@Override
	public int getLength() {

		// It is assumed that the getChildNodes call synchronized
		// the children. Therefore, we can access the first child
		// reference directly.
		int count = 0;

		for (ElemTemplateElement node = m_firstChild; node != null; node = node.m_nextSibling) {
			count++;
		}

		return count;
	} // getLength():int

	/**
	 * NodeList method: Return the Nth immediate child of this node, or null if
	 * the index is out of bounds.
	 * 
	 * @param index
	 *            Index of child to find
	 * @return org.w3c.dom.Node: the child node at given index
	 */
	@Override
	public Node item(int index) {

		// It is assumed that the getChildNodes call synchronized
		// the children. Therefore, we can access the first child
		// reference directly.
		ElemTemplateElement node = m_firstChild;

		for (int i = 0; i < index && node != null; i++) {
			node = node.m_nextSibling;
		}

		return node;
	} // item(int):Node

	/**
	 * Get the stylesheet owner.
	 * 
	 * @return The stylesheet owner
	 */
	@Override
	public Document getOwnerDocument() {
		return getStylesheet();
	}

	/**
	 * Get the owning xsl:template element.
	 * 
	 * @return The owning xsl:template element, this element if it is a
	 *         xsl:template, or null if not found.
	 */
	public ElemTemplate getOwnerXSLTemplate() {
		ElemTemplateElement el = this;
		int type = el.getXSLToken();
		while ((null != el) && (type != Constants.ELEMNAME_TEMPLATE)) {
			el = el.getParentElem();
			if (null != el)
				type = el.getXSLToken();
		}
		return (ElemTemplate) el;
	}

	/**
	 * Return the element name.
	 * 
	 * @return The element name
	 */
	@Override
	public String getTagName() {
		return getNodeName();
	}

	/**
	 * Tell if this element only has one text child, for optimization purposes.
	 * 
	 * @return true of this element only has one text literal child.
	 */
	public boolean hasTextLitOnly() {
		return m_hasTextLitOnly;
	}

	/**
	 * Return the base identifier.
	 * 
	 * @return The base identifier
	 */
	public String getBaseIdentifier() {

		// Should this always be absolute?
		return this.getSystemId();
	}

	/**
	 * line number where the current document event ends.
	 * 
	 * @serial
	 */
	private int m_lineNumber;

	/**
	 * line number where the current document event ends.
	 * 
	 * @serial
	 */
	private int m_endLineNumber;

	/**
	 * Return the line number where the current document event ends. Note that
	 * this is the line position of the first character after the text
	 * associated with the document event.
	 * 
	 * @return The line number, or -1 if none is available.
	 * @see #getColumnNumber
	 */
	public int getEndLineNumber() {
		return m_endLineNumber;
	}

	/**
	 * Return the line number where the current document event ends. Note that
	 * this is the line position of the first character after the text
	 * associated with the document event.
	 * 
	 * @return The line number, or -1 if none is available.
	 * @see #getColumnNumber
	 */
	public int getLineNumber() {
		return m_lineNumber;
	}

	/**
	 * the column number where the current document event ends.
	 * 
	 * @serial
	 */
	private int m_columnNumber;

	/**
	 * the column number where the current document event ends.
	 * 
	 * @serial
	 */
	private int m_endColumnNumber;

	/**
	 * Return the column number where the current document event ends. Note that
	 * this is the column number of the first character after the text
	 * associated with the document event. The first column in a line is
	 * position 1.
	 * 
	 * @return The column number, or -1 if none is available.
	 * @see #getLineNumber
	 */
	public int getEndColumnNumber() {
		return m_endColumnNumber;
	}

	/**
	 * Return the column number where the current document event ends. Note that
	 * this is the column number of the first character after the text
	 * associated with the document event. The first column in a line is
	 * position 1.
	 * 
	 * @return The column number, or -1 if none is available.
	 * @see #getLineNumber
	 */
	public int getColumnNumber() {
		return m_columnNumber;
	}

	/**
	 * Return the public identifier for the current document event.
	 * <p>
	 * This will be the public identifier
	 * 
	 * @return A string containing the public identifier, or null if none is
	 *         available.
	 * @see #getSystemId
	 */
	public String getPublicId() {
		return (null != m_parentNode) ? m_parentNode.getPublicId() : null;
	}

	/**
	 * Return the system identifier for the current document event.
	 * 
	 * <p>
	 * If the system identifier is a URL, the parser must resolve it fully
	 * before passing it to the application.
	 * </p>
	 * 
	 * @return A string containing the system identifier, or null if none is
	 *         available.
	 * @see #getPublicId
	 */
	public String getSystemId() {
		Stylesheet sheet = getStylesheet();
		return (sheet == null) ? null : sheet.getHref();
	}

	/**
	 * Set the location information for this element.
	 * 
	 * @param locator
	 *            Source Locator with location information for this element
	 */
	public void setLocaterInfo(SourceLocator locator) {
		m_lineNumber = locator.getLineNumber();
		m_columnNumber = locator.getColumnNumber();
	}

	/**
	 * Set the end location information for this element.
	 * 
	 * @param locator
	 *            Source Locator with location information for this element
	 */
	public void setEndLocaterInfo(SourceLocator locator) {
		m_endLineNumber = locator.getLineNumber();
		m_endColumnNumber = locator.getColumnNumber();
	}

	/**
	 * Tell if this element has the default space handling turned off or on
	 * according to the xml:space attribute.
	 * 
	 * @serial
	 */
	private boolean m_defaultSpace = true;

	/**
	 * Tell if this element only has one text child, for optimization purposes.
	 * 
	 * @serial
	 */
	private boolean m_hasTextLitOnly = false;

	/**
	 * Tell if this element only has one text child, for optimization purposes.
	 * 
	 * @serial
	 */
	protected boolean m_hasVariableDecl = false;

	public boolean hasVariableDecl() {
		return m_hasVariableDecl;
	}

	/**
	 * Set the "xml:space" attribute. A text node is preserved if an ancestor
	 * element of the text node has an xml:space attribute with a value of
	 * preserve, and no closer ancestor element has xml:space with a value of
	 * default.
	 * 
	 * @see <a href="http://www.w3.org/TR/xslt#strip">strip in XSLT
	 *      Specification</a>
	 * @see <a
	 *      href="http://www.w3.org/TR/xslt#section-Creating-Text">section-Creating-Text
	 *      in XSLT Specification</a>
	 * 
	 * @param v
	 *            Enumerated value, either Constants.ATTRVAL_PRESERVE or
	 *            Constants.ATTRVAL_STRIP.
	 */
	public void setXmlSpace(int v) {
		m_defaultSpace = ((Constants.ATTRVAL_STRIP == v) ? true : false);
	}

	/**
	 * Get the "xml:space" attribute. A text node is preserved if an ancestor
	 * element of the text node has an xml:space attribute with a value of
	 * preserve, and no closer ancestor element has xml:space with a value of
	 * default.
	 * 
	 * @see <a href="http://www.w3.org/TR/xslt#strip">strip in XSLT
	 *      Specification</a>
	 * @see <a
	 *      href="http://www.w3.org/TR/xslt#section-Creating-Text">section-Creating-Text
	 *      in XSLT Specification</a>
	 * 
	 * @return The value of the xml:space attribute
	 */
	public boolean getXmlSpace() {
		return m_defaultSpace;
	}

	/**
	 * The list of namespace declarations for this element only.
	 * 
	 * @serial
	 */
	private Vector m_declaredPrefixes;

	/**
	 * Return a table that contains all prefixes available within this element
	 * context.
	 * 
	 * @return Vector containing the prefixes available within this element
	 *         context
	 */
	public Vector getDeclaredPrefixes() {
		return m_declaredPrefixes;
	}

	/**
	 * From the SAX2 helper class, set the namespace table for this element.
	 * Take care to call resolveInheritedNamespaceDecls. after all namespace
	 * declarations have been added.
	 * 
	 * @param nsSupport
	 *            non-null reference to NamespaceSupport from the
	 *            ContentHandler.
	 * 
	 * @throws TransformerException
	 */
	public void setPrefixes(NamespaceSupport nsSupport)
			throws TransformerException {
		setPrefixes(nsSupport, false);
	}

	/**
	 * Copy the namespace declarations from the NamespaceSupport object. Take
	 * care to call resolveInheritedNamespaceDecls. after all namespace
	 * declarations have been added.
	 * 
	 * @param nsSupport
	 *            non-null reference to NamespaceSupport from the
	 *            ContentHandler.
	 * @param excludeXSLDecl
	 *            true if XSLT namespaces should be ignored.
	 * 
	 * @throws TransformerException
	 */
	public void setPrefixes(NamespaceSupport nsSupport, boolean excludeXSLDecl)
			throws TransformerException {

		Enumeration decls = nsSupport.getDeclaredPrefixes();

		while (decls.hasMoreElements()) {
			String prefix = (String) decls.nextElement();

			if (null == m_declaredPrefixes)
				m_declaredPrefixes = new Vector();

			String uri = nsSupport.getURI(prefix);

			if (excludeXSLDecl
					&& uri
							.equals(org.apache.xml.utils.Constants.S_XSLNAMESPACEURL))
				continue;

			// System.out.println("setPrefixes - "+prefix+", "+uri);
			XMLNSDecl decl = new XMLNSDecl(prefix, uri, false);

			m_declaredPrefixes.addElement(decl);
		}
	}

	/**
	 * Fullfill the PrefixResolver interface. Calling this for this class will
	 * throw an error.
	 * 
	 * @param prefix
	 *            The prefix to look up, which may be an empty string ("") for
	 *            the default Namespace.
	 * @param context
	 *            The node context from which to look up the URI.
	 * 
	 * @return null if the error listener does not choose to throw an exception.
	 */
	public String getNamespaceForPrefix(String prefix, org.w3c.dom.Node context) {
		this.error(XSLTErrorResources.ER_CANT_RESOLVE_NSPREFIX, null);

		return null;
	}

	/**
	 * Given a namespace, get the corrisponding prefix. 9/15/00: This had been
	 * iteratively examining the m_declaredPrefixes field for this node and its
	 * parents. That makes life difficult for the compilation experiment, which
	 * doesn't have a static vector of local declarations. Replaced a recursive
	 * solution, which permits easier subclassing/overriding.
	 * 
	 * @param prefix
	 *            non-null reference to prefix string, which should map to a
	 *            namespace URL.
	 * 
	 * @return The namespace URL that the prefix maps to, or null if no mapping
	 *         can be found.
	 */
	public String getNamespaceForPrefix(String prefix) {
		// if (null != prefix && prefix.equals("xmlns"))
		// {
		// return Constants.S_XMLNAMESPACEURI;
		// }

		Vector nsDecls = m_declaredPrefixes;

		if (null != nsDecls) {
			int n = nsDecls.size();
			if (prefix.equals(Constants.ATTRVAL_DEFAULT_PREFIX)) {
				prefix = "";
			}

			for (int i = 0; i < n; i++) {
				XMLNSDecl decl = (XMLNSDecl) nsDecls.elementAt(i);

				if (prefix.equals(decl.getPrefix()))
					return decl.getURI();
			}
		}

		// Not found; ask our ancestors
		if (null != m_parentNode)
			return m_parentNode.getNamespaceForPrefix(prefix);

		// JJK: No ancestors; try implicit
		// %REVIEW% Are there literals somewhere that we should use instead?
		// %REVIEW% Is this really the best place to patch?
		if ("xml".equals(prefix))
			return "http://www.w3.org/XML/1998/namespace";

		// No parent, so no definition
		return null;
	}

	/**
	 * The table of {@link XMLNSDecl}s for this element and all parent
	 * elements, screened for excluded prefixes.
	 * 
	 * @serial
	 */
	Vector m_prefixTable;

	/**
	 * Return a table that contains all prefixes available within this element
	 * context.
	 * 
	 * @return reference to vector of {@link XMLNSDecl}s, which may be null.
	 */
	public Vector getPrefixes() {
		return m_prefixTable;
	}

	/**
	 * Get whether or not the passed URL is contained flagged by the
	 * "extension-element-prefixes" property. This method is overridden by
	 * {@link ElemLiteralResult#containsExcludeResultPrefix}.
	 * 
	 * @see <a
	 *      href="http://www.w3.org/TR/xslt#extension-element">extension-element
	 *      in XSLT Specification</a>
	 * 
	 * @param prefix
	 *            non-null reference to prefix that might be excluded.
	 * 
	 * @return true if the prefix should normally be excluded.
	 */
	public boolean containsExcludeResultPrefix(String prefix, String uri) {
		ElemTemplateElement parent = this.getParentElem();
		if (null != parent)
			return parent.containsExcludeResultPrefix(prefix, uri);

		return false;
	}

	/**
	 * Tell if the result namespace decl should be excluded. Should be called
	 * before namespace aliasing (I think).
	 * 
	 * @param prefix
	 *            non-null reference to prefix.
	 * @param uri
	 *            reference to namespace that prefix maps to, which is protected
	 *            for null, but should really never be passed as null.
	 * 
	 * @return true if the given namespace should be excluded.
	 * 
	 * @throws TransformerException
	 */
	private boolean excludeResultNSDecl(String prefix, String uri)
			throws TransformerException {

		if (uri != null) {
			if (uri.equals(org.apache.xml.utils.Constants.S_XSLNAMESPACEURL)
					|| getStylesheet().containsExtensionElementURI(uri))
				return true;

			if (containsExcludeResultPrefix(prefix, uri))
				return true;
		}

		return false;
	}

	/**
	 * Combine the parent's namespaces with this namespace for fast processing,
	 * taking care to reference the parent's namespace if this namespace adds
	 * nothing new. (Recursive method, walking the elements depth-first,
	 * processing parents before children). Note that this method builds
	 * m_prefixTable with aliased namespaces, *not* the original namespaces.
	 * 
	 * @throws TransformerException
	 */
	public void resolvePrefixTables() throws TransformerException {
		// Always start with a fresh prefix table!
		m_prefixTable = null;

		// If we have declared declarations, then we look for
		// a parent that has namespace decls, and add them
		// to this element's decls. Otherwise we just point
		// to the parent that has decls.
		if (null != this.m_declaredPrefixes) {
			StylesheetRoot stylesheet = this.getStylesheetRoot();

			// Add this element's declared prefixes to the
			// prefix table.
			int n = m_declaredPrefixes.size();

			for (int i = 0; i < n; i++) {
				XMLNSDecl decl = (XMLNSDecl) m_declaredPrefixes.elementAt(i);
				String prefix = decl.getPrefix();
				String uri = decl.getURI();
				if (null == uri)
					uri = "";
				boolean shouldExclude = excludeResultNSDecl(prefix, uri);

				// Create a new prefix table if one has not already been
				// created.
				if (null == m_prefixTable)
					m_prefixTable = new Vector();

				NamespaceAlias nsAlias = stylesheet
						.getNamespaceAliasComposed(uri);
				if (null != nsAlias) {
					// Should I leave the non-aliased element in the table as
					// an excluded element?

					// The exclusion should apply to the non-aliased prefix, so
					// we don't calculate it here. -sb
					// Use stylesheet prefix, as per xsl WG
					decl = new XMLNSDecl(nsAlias.getStylesheetPrefix(), nsAlias
							.getResultNamespace(), shouldExclude);
				} else
					decl = new XMLNSDecl(prefix, uri, shouldExclude);

				m_prefixTable.addElement(decl);

			}
		}

		ElemTemplateElement parent = this.getParentNodeElem();

		if (null != parent) {

			// The prefix table of the parent should never be null!
			Vector prefixes = parent.m_prefixTable;

			if (null == m_prefixTable && !needToCheckExclude()) {

				// Nothing to combine, so just use parent's table!
				this.m_prefixTable = parent.m_prefixTable;
			} else {

				// Add the prefixes from the parent's prefix table.
				int n = prefixes.size();

				for (int i = 0; i < n; i++) {
					XMLNSDecl decl = (XMLNSDecl) prefixes.elementAt(i);
					boolean shouldExclude = excludeResultNSDecl(decl
							.getPrefix(), decl.getURI());

					if (shouldExclude != decl.getIsExcluded()) {
						decl = new XMLNSDecl(decl.getPrefix(), decl.getURI(),
								shouldExclude);
					}

					// m_prefixTable.addElement(decl);
					addOrReplaceDecls(decl);
				}
			}
		} else if (null == m_prefixTable) {

			// Must be stylesheet element without any result prefixes!
			m_prefixTable = new Vector();
		}
	}

	/**
	 * Add or replace this namespace declaration in list of namespaces in scope
	 * for this element.
	 * 
	 * @param newDecl
	 *            namespace declaration to add to list
	 */
	void addOrReplaceDecls(XMLNSDecl newDecl) {
		int n = m_prefixTable.size();

		for (int i = n - 1; i >= 0; i--) {
			XMLNSDecl decl = (XMLNSDecl) m_prefixTable.elementAt(i);

			if (decl.getPrefix().equals(newDecl.getPrefix())) {
				return;
			}
		}
		m_prefixTable.addElement(newDecl);

	}

	/**
	 * Return whether we need to check namespace prefixes against and exclude
	 * result prefixes list.
	 */
	boolean needToCheckExclude() {
		return false;
	}

	/**
	 * Send startPrefixMapping events to the result tree handler for all
	 * declared prefix mappings in the stylesheet.
	 * 
	 * @param transformer
	 *            non-null reference to the the current transform-time state.
	 * 
	 * @throws TransformerException
	 */
	void executeNSDecls(TransformerImpl transformer)
			throws TransformerException {
		executeNSDecls(transformer, null);
	}

	/**
	 * Send startPrefixMapping events to the result tree handler for all
	 * declared prefix mappings in the stylesheet.
	 * 
	 * @param transformer
	 *            non-null reference to the the current transform-time state.
	 * @param ignorePrefix
	 *            string prefix to not startPrefixMapping
	 * 
	 * @throws TransformerException
	 */
	void executeNSDecls(TransformerImpl transformer, String ignorePrefix)
			throws TransformerException {
		try {
			if (null != m_prefixTable) {
				SerializationHandler rhandler = transformer
						.getResultTreeHandler();
				int n = m_prefixTable.size();

				for (int i = n - 1; i >= 0; i--) {
					XMLNSDecl decl = (XMLNSDecl) m_prefixTable.elementAt(i);

					if (!decl.getIsExcluded()
							&& !(null != ignorePrefix && decl.getPrefix()
									.equals(ignorePrefix))) {
						rhandler.startPrefixMapping(decl.getPrefix(), decl
								.getURI(), true);
					}
				}
			}
		} catch (org.xml.sax.SAXException se) {
			throw new TransformerException(se);
		}
	}

	/**
	 * Send endPrefixMapping events to the result tree handler for all declared
	 * prefix mappings in the stylesheet.
	 * 
	 * @param transformer
	 *            non-null reference to the the current transform-time state.
	 * 
	 * @throws TransformerException
	 */
	void unexecuteNSDecls(TransformerImpl transformer)
			throws TransformerException {
		unexecuteNSDecls(transformer, null);
	}

	/**
	 * Send endPrefixMapping events to the result tree handler for all declared
	 * prefix mappings in the stylesheet.
	 * 
	 * @param transformer
	 *            non-null reference to the the current transform-time state.
	 * @param ignorePrefix
	 *            string prefix to not endPrefixMapping
	 * 
	 * @throws TransformerException
	 */
	void unexecuteNSDecls(TransformerImpl transformer, String ignorePrefix)
			throws TransformerException {

		try {
			if (null != m_prefixTable) {
				SerializationHandler rhandler = transformer
						.getResultTreeHandler();
				int n = m_prefixTable.size();

				for (int i = 0; i < n; i++) {
					XMLNSDecl decl = (XMLNSDecl) m_prefixTable.elementAt(i);

					if (!decl.getIsExcluded()
							&& !(null != ignorePrefix && decl.getPrefix()
									.equals(ignorePrefix))) {
						rhandler.endPrefixMapping(decl.getPrefix());
					}
				}
			}
		} catch (org.xml.sax.SAXException se) {
			throw new TransformerException(se);
		}
	}

	/**
	 * The *relative* document order number of this element.
	 * 
	 * @serial
	 */
	protected int m_docOrderNumber = -1;

	/**
	 * Set the UID (document order index).
	 * 
	 * @param i
	 *            Index of this child.
	 */
	public void setUid(int i) {
		m_docOrderNumber = i;
	}

	/**
	 * Get the UID (document order index).
	 * 
	 * @return Index of this child
	 */
	public int getUid() {
		return m_docOrderNumber;
	}

	/**
	 * Parent node.
	 * 
	 * @serial
	 */
	protected ElemTemplateElement m_parentNode;

	/**
	 * Get the parent as a Node.
	 * 
	 * @return This node's parent node
	 */
	@Override
	public Node getParentNode() {
		return m_parentNode;
	}

	/**
	 * Get the parent as an ElemTemplateElement.
	 * 
	 * @return This node's parent as an ElemTemplateElement
	 */
	public ElemTemplateElement getParentElem() {
		return m_parentNode;
	}

	/**
	 * Set the parent as an ElemTemplateElement.
	 * 
	 * @param p
	 *            This node's parent as an ElemTemplateElement
	 */
	public void setParentElem(ElemTemplateElement p) {
		m_parentNode = p;
	}

	/**
	 * Next sibling.
	 * 
	 * @serial
	 */
	ElemTemplateElement m_nextSibling;

	/**
	 * Get the next sibling (as a Node) or return null.
	 * 
	 * @return this node's next sibling or null
	 */
	@Override
	public Node getNextSibling() {
		return m_nextSibling;
	}

	/**
	 * Get the previous sibling (as a Node) or return null. Note that this may
	 * be expensive if the parent has many kids; we accept that price in
	 * exchange for avoiding the prev pointer TODO: If we were sure parents and
	 * sibs are always ElemTemplateElements, we could hit the fields directly
	 * rather than thru accessors.
	 * 
	 * @return This node's previous sibling or null
	 */
	@Override
	public Node getPreviousSibling() {

		Node walker = getParentNode(), prev = null;

		if (walker != null)
			for (walker = walker.getFirstChild(); walker != null; prev = walker, walker = walker
					.getNextSibling()) {
				if (walker == this)
					return prev;
			}

		return null;
	}

	/**
	 * Get the previous sibling (as a Node) or return null. Note that this may
	 * be expensive if the parent has many kids; we accept that price in
	 * exchange for avoiding the prev pointer TODO: If we were sure parents and
	 * sibs are always ElemTemplateElements, we could hit the fields directly
	 * rather than thru accessors.
	 * 
	 * @return This node's previous sibling or null
	 */
	public ElemTemplateElement getPreviousSiblingElem() {

		ElemTemplateElement walker = getParentNodeElem();
		ElemTemplateElement prev = null;

		if (walker != null)
			for (walker = walker.getFirstChildElem(); walker != null; prev = walker, walker = walker
					.getNextSiblingElem()) {
				if (walker == this)
					return prev;
			}

		return null;
	}

	/**
	 * Get the next sibling (as a ElemTemplateElement) or return null.
	 * 
	 * @return This node's next sibling (as a ElemTemplateElement) or null
	 */
	public ElemTemplateElement getNextSiblingElem() {
		return m_nextSibling;
	}

	/**
	 * Get the parent element.
	 * 
	 * @return This node's next parent (as a ElemTemplateElement) or null
	 */
	public ElemTemplateElement getParentNodeElem() {
		return m_parentNode;
	}

	/**
	 * First child.
	 * 
	 * @serial
	 */
	ElemTemplateElement m_firstChild;

	/**
	 * Get the first child as a Node.
	 * 
	 * @return This node's first child or null
	 */
	@Override
	public Node getFirstChild() {
		return m_firstChild;
	}

	/**
	 * Get the first child as a ElemTemplateElement.
	 * 
	 * @return This node's first child (as a ElemTemplateElement) or null
	 */
	public ElemTemplateElement getFirstChildElem() {
		return m_firstChild;
	}

	/**
	 * Get the last child.
	 * 
	 * @return This node's last child
	 */
	@Override
	public Node getLastChild() {

		ElemTemplateElement lastChild = null;

		for (ElemTemplateElement node = m_firstChild; node != null; node = node.m_nextSibling) {
			lastChild = node;
		}

		return lastChild;
	}

	/**
	 * Get the last child.
	 * 
	 * @return This node's last child
	 */
	public ElemTemplateElement getLastChildElem() {

		ElemTemplateElement lastChild = null;

		for (ElemTemplateElement node = m_firstChild; node != null; node = node.m_nextSibling) {
			lastChild = node;
		}

		return lastChild;
	}

	/** DOM backpointer that this element originated from. */
	transient private org.w3c.dom.Node m_DOMBackPointer;

	/**
	 * If this stylesheet was created from a DOM, get the DOM backpointer that
	 * this element originated from. For tooling use.
	 * 
	 * @return DOM backpointer that this element originated from or null.
	 */
	public org.w3c.dom.Node getDOMBackPointer() {
		return m_DOMBackPointer;
	}

	/**
	 * If this stylesheet was created from a DOM, set the DOM backpointer that
	 * this element originated from. For tooling use.
	 * 
	 * @param n
	 *            DOM backpointer that this element originated from.
	 */
	public void setDOMBackPointer(org.w3c.dom.Node n) {
		m_DOMBackPointer = n;
	}

	/**
	 * Compares this object with the specified object for precedence order. The
	 * order is determined by the getImportCountComposed() of the containing
	 * composed stylesheet and the getUid() of this element. Returns a negative
	 * integer, zero, or a positive integer as this object is less than, equal
	 * to, or greater than the specified object.
	 * 
	 * @param o
	 *            The object to be compared to this object
	 * @return a negative integer, zero, or a positive integer as this object is
	 *         less than, equal to, or greater than the specified object.
	 * @throws ClassCastException
	 *             if the specified object's type prevents it from being
	 *             compared to this Object.
	 */
	public int compareTo(Object o) throws ClassCastException {

		ElemTemplateElement ro = (ElemTemplateElement) o;
		int roPrecedence = ro.getStylesheetComposed().getImportCountComposed();
		int myPrecedence = this.getStylesheetComposed()
				.getImportCountComposed();

		if (myPrecedence < roPrecedence)
			return -1;
		else if (myPrecedence > roPrecedence)
			return 1;
		else
			return this.getUid() - ro.getUid();
	}

	/**
	 * Get information about whether or not an element should strip whitespace.
	 * 
	 * @see <a href="http://www.w3.org/TR/xslt#strip">strip in XSLT
	 *      Specification</a>
	 * 
	 * @param support
	 *            The XPath runtime state.
	 * @param targetElement
	 *            Element to check
	 * 
	 * @return true if the whitespace should be stripped.
	 * 
	 * @throws TransformerException
	 */
	public boolean shouldStripWhiteSpace(org.apache.xpath.XPathContext support,
			org.w3c.dom.Element targetElement) throws TransformerException {
		StylesheetRoot sroot = this.getStylesheetRoot();
		return (null != sroot) ? sroot.shouldStripWhiteSpace(support,
				targetElement) : false;
	}

	/**
	 * Get information about whether or not whitespace can be stripped.
	 * 
	 * @see <a href="http://www.w3.org/TR/xslt#strip">strip in XSLT
	 *      Specification</a>
	 * 
	 * @return true if the whitespace can be stripped.
	 */
	public boolean canStripWhiteSpace() {
		StylesheetRoot sroot = this.getStylesheetRoot();
		return (null != sroot) ? sroot.canStripWhiteSpace() : false;
	}

	/**
	 * Tell if this element can accept variable declarations.
	 * 
	 * @return true if the element can accept and process variable declarations.
	 */
	public boolean canAcceptVariables() {
		return true;
	}

	// =============== ExpressionNode methods ================

	/**
	 * Set the parent of this node.
	 * 
	 * @param n
	 *            Must be a ElemTemplateElement.
	 */
	public void exprSetParent(ExpressionNode n) {
		// This obviously requires that only a ElemTemplateElement can
		// parent a node of this type.
		setParentElem((ElemTemplateElement) n);
	}

	/**
	 * Get the ExpressionNode parent of this node.
	 */
	public ExpressionNode exprGetParent() {
		return getParentElem();
	}

	/**
	 * This method tells the node to add its argument to the node's list of
	 * children.
	 * 
	 * @param n
	 *            Must be a ElemTemplateElement.
	 */
	public void exprAddChild(ExpressionNode n, int i) {
		appendChild((ElemTemplateElement) n);
	}

	/**
	 * This method returns a child node. The children are numbered from zero,
	 * left to right.
	 */
	public ExpressionNode exprGetChild(int i) {
		return (ExpressionNode) item(i);
	}

	/** Return the number of children the node has. */
	public int exprGetNumChildren() {
		return getLength();
	}

	/**
	 * Accept a visitor and call the appropriate method for this class.
	 * 
	 * @param visitor
	 *            The visitor whose appropriate method will be called.
	 * @return true if the children of the object should be visited.
	 */
	protected boolean accept(XSLTVisitor visitor) {
		return visitor.visitInstruction(this);
	}

	/**
	 * @see XSLTVisitable#callVisitors(XSLTVisitor)
	 */
	public void callVisitors(XSLTVisitor visitor) {
		if (accept(visitor)) {
			callChildVisitors(visitor);
		}
	}

	/**
	 * Call the children visitors.
	 * 
	 * @param visitor
	 *            The visitor whose appropriate method will be called.
	 */
	protected void callChildVisitors(XSLTVisitor visitor, boolean callAttributes) {
		for (ElemTemplateElement node = m_firstChild; node != null; node = node.m_nextSibling) {
			node.callVisitors(visitor);
		}
	}

	/**
	 * Call the children visitors.
	 * 
	 * @param visitor
	 *            The visitor whose appropriate method will be called.
	 */
	protected void callChildVisitors(XSLTVisitor visitor) {
		callChildVisitors(visitor, true);
	}

	/**
	 * @see PrefixResolver#handlesNullPrefixes()
	 */
	public boolean handlesNullPrefixes() {
		return false;
	}

}