/*
 * Copyright (c) 2006, 2017, Oracle and/or its affiliates. All rights reserved.
 */
/*
 * 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.
 */

package com.sun.org.apache.xalan.internal.xsltc.compiler;

import com.sun.org.apache.bcel.internal.generic.ANEWARRAY;
import com.sun.org.apache.bcel.internal.generic.BasicType;
import com.sun.org.apache.bcel.internal.generic.CHECKCAST;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.DUP_X1;
import com.sun.org.apache.bcel.internal.generic.GETFIELD;
import com.sun.org.apache.bcel.internal.generic.ICONST;
import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.NEW;
import com.sun.org.apache.bcel.internal.generic.NEWARRAY;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.DOM;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ErrorMsg;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.xml.sax.Attributes;
import org.xml.sax.helpers.AttributesImpl;


Author:
Jacek Ambroziak, Santiago Pericas-Geertsen, G. Todd Miller, Morten Jorensen, Erwin Bolwidt , John Howard 
@LastModified
: Nov 2017/**
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 * @author G. Todd Miller
 * @author Morten Jorensen
 * @author Erwin Bolwidt <ejb@klomp.org>
 * @author John Howard <JohnH@schemasoft.com>
 * @LastModified: Nov 2017
 */
public abstract class SyntaxTreeNode implements Constants {

    // Reference to the AST parser
    private Parser _parser;

    // AST navigation pointers
    protected SyntaxTreeNode _parent;          // Parent node
    private Stylesheet       _stylesheet;      // Stylesheet ancestor node
    private Template         _template;        // Template ancestor node
    private final List<SyntaxTreeNode> _contents = new ArrayList<>(2); // Child nodes

    // Element description data
    protected QName _qname;                    // The element QName
    private int _line;                         // Source file line number
    protected AttributesImpl _attributes = null;   // Attributes of this element
    private Map<String, String> _prefixMapping = null; // Namespace declarations

    // Sentinel - used to denote unrecognised syntaxt tree nodes.
    protected static final SyntaxTreeNode Dummy = new AbsolutePathPattern(null);

    // These two are used for indenting nodes in the AST (debug output)
    protected static final int IndentIncrement = 4;
    private static final char[] _spaces =
        "                                                       ".toCharArray();

    
Creates a new SyntaxTreeNode with a 'null' QName and no source file
line number reference.
/**
     * Creates a new SyntaxTreeNode with a 'null' QName and no source file
     * line number reference.
     */
    public SyntaxTreeNode() {
        _line = 0;
        _qname = null;
    }

    
Creates a new SyntaxTreeNode with a 'null' QName.
Params:
line – Source file line number reference/**
     * Creates a new SyntaxTreeNode with a 'null' QName.
     * @param line Source file line number reference
     */
    public SyntaxTreeNode(int line) {
        _line = line;
        _qname = null;
    }

    
Creates a new SyntaxTreeNode with no source file line number reference.
Params:
uri – The element's namespace URI
prefix – The element's namespace prefix
local – The element's local name/**
     * Creates a new SyntaxTreeNode with no source file line number reference.
     * @param uri The element's namespace URI
     * @param prefix The element's namespace prefix
     * @param local The element's local name
     */
    public SyntaxTreeNode(String uri, String prefix, String local) {
        _line = 0;
        setQName(uri, prefix, local);
    }

    
Set the source file line number for this element
Params:
line – The source file line number./**
     * Set the source file line number for this element
     * @param line The source file line number.
     */
    protected final void setLineNumber(int line) {
        _line = line;
    }

    
Get the source file line number for this element. If unavailable, lookup
in ancestors.
Returns:
The source file line number./**
     * Get the source file line number for this element. If unavailable, lookup
     * in ancestors.
     *
     * @return The source file line number.
     */
    public final int getLineNumber() {
        if (_line > 0) return _line;
        SyntaxTreeNode parent = getParent();
        return (parent != null) ? parent.getLineNumber() : 0;
    }

    
Set the QName for the syntax tree node.
Params:
qname – The QName for the syntax tree node/**
     * Set the QName for the syntax tree node.
     * @param qname The QName for the syntax tree node
     */
    protected void setQName(QName qname) {
        _qname = qname;
    }

    
Set the QName for the SyntaxTreeNode
Params:
uri – The element's namespace URI
prefix – The element's namespace prefix
local – The element's local name/**
     * Set the QName for the SyntaxTreeNode
     * @param uri The element's namespace URI
     * @param prefix The element's namespace prefix
     * @param local The element's local name
     */
    protected void setQName(String uri, String prefix, String localname) {
        _qname = new QName(uri, prefix, localname);
    }

    
Set the QName for the SyntaxTreeNode
Params:
qname – The QName for the syntax tree node/**
     * Set the QName for the SyntaxTreeNode
     * @param qname The QName for the syntax tree node
     */
    protected QName getQName() {
        return(_qname);
    }

    
Set the attributes for this SyntaxTreeNode.
Params:
attributes – Attributes for the element. Must be passed in as an
                  implementation of org.xml.sax.Attributes./**
     * Set the attributes for this SyntaxTreeNode.
     * @param attributes Attributes for the element. Must be passed in as an
     *                   implementation of org.xml.sax.Attributes.
     */
    protected void setAttributes(AttributesImpl attributes) {
        _attributes = attributes;
    }

    
Returns a value for an attribute from the source element.
Params:
qname – The QName of the attribute to return.
Returns:
The value of the attribute of name 'qname'./**
     * Returns a value for an attribute from the source element.
     * @param qname The QName of the attribute to return.
     * @return The value of the attribute of name 'qname'.
     */
    protected String getAttribute(String qname) {
        if (_attributes == null) {
            return EMPTYSTRING;
        }
        final String value = _attributes.getValue(qname);
        return (value == null || value.equals(EMPTYSTRING)) ?
            EMPTYSTRING : value;
    }

    protected String getAttribute(String prefix, String localName) {
        return getAttribute(prefix + ':' + localName);
    }

    protected boolean hasAttribute(String qname) {
        return (_attributes != null && _attributes.getValue(qname) != null);
    }

    protected void addAttribute(String qname, String value) {
        int index = _attributes.getIndex(qname);
        if (index != -1) {
            _attributes.setAttribute(index, "", Util.getLocalName(qname),
                    qname, "CDATA", value);
        }
        else {
            _attributes.addAttribute("", Util.getLocalName(qname), qname,
                    "CDATA", value);
        }
    }

    
Returns a list of all attributes declared for the element represented by
this syntax tree node.
Returns:
Attributes for this syntax tree node/**
     * Returns a list of all attributes declared for the element represented by
     * this syntax tree node.
     * @return Attributes for this syntax tree node
     */
    protected Attributes getAttributes() {
        return(_attributes);
    }

    
Sets the prefix mapping for the namespaces that were declared in this
element. This does not include all prefix mappings in scope, so one
may have to check ancestor elements to get all mappings that are in
in scope. The prefixes must be passed in as a Map that maps
namespace prefixes (String objects) to namespace URIs (also String).
Params:
mapping – The Map containing the mappings./**
     * Sets the prefix mapping for the namespaces that were declared in this
     * element. This does not include all prefix mappings in scope, so one
     * may have to check ancestor elements to get all mappings that are in
     * in scope. The prefixes must be passed in as a Map that maps
     * namespace prefixes (String objects) to namespace URIs (also String).
     * @param mapping The Map containing the mappings.
     */
    protected void setPrefixMapping(Map<String, String> mapping) {
        _prefixMapping = mapping;
    }

    
Returns a Map containing the prefix mappings that were declared
for this element. This does not include all prefix mappings in scope,
so one may have to check ancestor elements to get all mappings that are
in in scope.
Returns:
Prefix mappings (for this element only)./**
     * Returns a Map containing the prefix mappings that were declared
     * for this element. This does not include all prefix mappings in scope,
     * so one may have to check ancestor elements to get all mappings that are
     * in in scope.
     * @return Prefix mappings (for this element only).
     */
    protected Map<String, String> getPrefixMapping() {
        return _prefixMapping;
    }

    
Adds a single prefix mapping to this syntax tree node.
Params:
prefix – Namespace prefix.
uri – Namespace URI./**
     * Adds a single prefix mapping to this syntax tree node.
     * @param prefix Namespace prefix.
     * @param uri Namespace URI.
     */
    protected void addPrefixMapping(String prefix, String uri) {
        if (_prefixMapping == null)
            _prefixMapping = new HashMap<>();
        _prefixMapping.put(prefix, uri);
    }

    
Returns any namespace URI that is in scope for a given prefix. This
method checks namespace mappings for this element, and if necessary
for ancestor elements as well (ie. if the prefix maps to an URI in this
scope then you'll definately get the URI from this method).
Params:
prefix – Namespace prefix.
Returns:
Namespace URI./**
     * Returns any namespace URI that is in scope for a given prefix. This
     * method checks namespace mappings for this element, and if necessary
     * for ancestor elements as well (ie. if the prefix maps to an URI in this
     * scope then you'll definately get the URI from this method).
     * @param prefix Namespace prefix.
     * @return Namespace URI.
     */
    protected String lookupNamespace(String prefix) {
        // Initialise the output (default is 'null' for undefined)
        String uri = null;

        // First look up the prefix/uri mapping in our own map...
        if (_prefixMapping != null)
            uri = _prefixMapping.get(prefix);
        // ... but if we can't find it there we ask our parent for the mapping
        if ((uri == null) && (_parent != null)) {
            uri = _parent.lookupNamespace(prefix);
            if ((prefix == Constants.EMPTYSTRING) && (uri == null))
                uri = Constants.EMPTYSTRING;
        }
        // ... and then we return whatever URI we've got.
        return(uri);
    }

    
Returns any namespace prefix that is mapped to a prefix in the current
scope. This method checks namespace mappings for this element, and if
necessary for ancestor elements as well (ie. if the URI is declared
within the current scope then you'll definately get the prefix from
this method). Note that this is a very slow method and consequentially
it should only be used strictly when needed.
Params:
uri – Namespace URI.
Returns:
Namespace prefix./**
     * Returns any namespace prefix that is mapped to a prefix in the current
     * scope. This method checks namespace mappings for this element, and if
     * necessary for ancestor elements as well (ie. if the URI is declared
     * within the current scope then you'll definately get the prefix from
     * this method). Note that this is a very slow method and consequentially
     * it should only be used strictly when needed.
     * @param uri Namespace URI.
     * @return Namespace prefix.
     */
    protected String lookupPrefix(String uri) {
        // Initialise the output (default is 'null' for undefined)
        String prefix = null;

        // First look up the prefix/uri mapping in our own map...
        if ((_prefixMapping != null) &&
            (_prefixMapping.containsValue(uri))) {
            for (Map.Entry<String, String> entry : _prefixMapping.entrySet()) {
                prefix = entry.getKey();
                String mapsTo = entry.getValue();
                if (mapsTo.equals(uri)) return(prefix);
            }
        }
        // ... but if we can't find it there we ask our parent for the mapping
        else if (_parent != null) {
            prefix = _parent.lookupPrefix(uri);
            if ((uri == Constants.EMPTYSTRING) && (prefix == null))
                prefix = Constants.EMPTYSTRING;
        }
        return(prefix);
    }

    
Set this node's parser. The parser (the XSLT parser) gives this
syntax tree node access to the symbol table and XPath parser.
Params:
parser – The XSLT parser./**
     * Set this node's parser. The parser (the XSLT parser) gives this
     * syntax tree node access to the symbol table and XPath parser.
     * @param parser The XSLT parser.
     */
    protected void setParser(Parser parser) {
        _parser = parser;
    }

    
Returns this node's XSLT parser.
Returns:
The XSLT parser./**
     * Returns this node's XSLT parser.
     * @return The XSLT parser.
     */
    public final Parser getParser() {
        return _parser;
    }

    
Set this syntax tree node's parent node, if unset. For
re-parenting just use node._parent = newparent.
Params:
parent – The parent node./**
     * Set this syntax tree node's parent node, if unset. For
     * re-parenting just use <code>node._parent = newparent</code>.
     *
     * @param parent The parent node.
     */
    protected void setParent(SyntaxTreeNode parent) {
        if (_parent == null) _parent = parent;
    }

    
Returns this syntax tree node's parent node.
Returns:
The parent syntax tree node./**
     * Returns this syntax tree node's parent node.
     * @return The parent syntax tree node.
     */
    protected final SyntaxTreeNode getParent() {
        return _parent;
    }

    
Returns 'true' if this syntax tree node is the Sentinal node.
Returns:
'true' if this syntax tree node is the Sentinal node./**
     * Returns 'true' if this syntax tree node is the Sentinal node.
     * @return 'true' if this syntax tree node is the Sentinal node.
     */
    protected final boolean isDummy() {
        return this == Dummy;
    }

    
Get the import precedence of this element. The import precedence equals
the import precedence of the stylesheet in which this element occured.
Returns:
The import precedence of this syntax tree node./**
     * Get the import precedence of this element. The import precedence equals
     * the import precedence of the stylesheet in which this element occured.
     * @return The import precedence of this syntax tree node.
     */
    protected int getImportPrecedence() {
        Stylesheet stylesheet = getStylesheet();
        if (stylesheet == null) return Integer.MIN_VALUE;
        return stylesheet.getImportPrecedence();
    }

    
Get the Stylesheet node that represents the  element
that this node occured under.
Returns:
The Stylesheet ancestor node of this node./**
     * Get the Stylesheet node that represents the <xsl:stylesheet/> element
     * that this node occured under.
     * @return The Stylesheet ancestor node of this node.
     */
    public Stylesheet getStylesheet() {
        if (_stylesheet == null) {
            SyntaxTreeNode parent = this;
            while (parent != null) {
                if (parent instanceof Stylesheet)
                    return((Stylesheet)parent);
                parent = parent.getParent();
            }
            _stylesheet = (Stylesheet)parent;
        }
        return(_stylesheet);
    }

    
Get the Template node that represents the  element
that this node occured under. Note that this method will return 'null'
for nodes that represent top-level elements.
Returns:
The Template ancestor node of this node or 'null'./**
     * Get the Template node that represents the <xsl:template/> element
     * that this node occured under. Note that this method will return 'null'
     * for nodes that represent top-level elements.
     * @return The Template ancestor node of this node or 'null'.
     */
    protected Template getTemplate() {
        if (_template == null) {
            SyntaxTreeNode parent = this;
            while ((parent != null) && (!(parent instanceof Template)))
                parent = parent.getParent();
            _template = (Template)parent;
        }
        return(_template);
    }

    
Returns a reference to the XSLTC (XSLT compiler) in use.
Returns:
XSLTC - XSLT compiler./**
     * Returns a reference to the XSLTC (XSLT compiler) in use.
     * @return XSLTC - XSLT compiler.
     */
    protected final XSLTC getXSLTC() {
        return _parser.getXSLTC();
    }

    
Returns the XSLT parser's symbol table.
Returns:
Symbol table./**
     * Returns the XSLT parser's symbol table.
     * @return Symbol table.
     */
    protected final SymbolTable getSymbolTable() {
        return (_parser == null) ? null : _parser.getSymbolTable();
    }

    
Parse the contents of this syntax tree nodes (child nodes, XPath
expressions, patterns and functions). The default behaviour is to parser
the syntax tree node's children (since there are no common expressions,
patterns, etc. that can be handled in this base class.
Params:
parser – reference to the XSLT parser/**
     * Parse the contents of this syntax tree nodes (child nodes, XPath
     * expressions, patterns and functions). The default behaviour is to parser
     * the syntax tree node's children (since there are no common expressions,
     * patterns, etc. that can be handled in this base class.
     * @param parser reference to the XSLT parser
     */
    public void parseContents(Parser parser) {
        parseChildren(parser);
    }

    
Parse all children of this syntax tree node. This method is normally
called by the parseContents() method.
Params:
parser – reference to the XSLT parser/**
     * Parse all children of this syntax tree node. This method is normally
     * called by the parseContents() method.
     * @param parser reference to the XSLT parser
     */
    protected final void parseChildren(Parser parser) {

        List<QName> locals = null;   // only create when needed

        for (SyntaxTreeNode child : _contents) {
            parser.getSymbolTable().setCurrentNode(child);
            child.parseContents(parser);
            // if variable or parameter, add it to scope
            final QName varOrParamName = updateScope(parser, child);
            if (varOrParamName != null) {
                if (locals == null) {
                    locals = new ArrayList<>(2);
                }
                locals.add(varOrParamName);
            }
        }

        parser.getSymbolTable().setCurrentNode(this);

        // after the last element, remove any locals from scope
        if (locals != null) {
            for (QName varOrParamName : locals) {
                parser.removeVariable(varOrParamName);
            }
        }
    }

    
Add a node to the current scope and return name of a variable or
parameter if the node represents a variable or a parameter.
/**
     * Add a node to the current scope and return name of a variable or
     * parameter if the node represents a variable or a parameter.
     */
    protected QName updateScope(Parser parser, SyntaxTreeNode node) {
        if (node instanceof Variable) {
            final Variable var = (Variable)node;
            parser.addVariable(var);
            return var.getName();
        }
        else if (node instanceof Param) {
            final Param param = (Param)node;
            parser.addParameter(param);
            return param.getName();
        }
        else {
            return null;
        }
    }

    
Type check the children of this node. The type check phase may add
coercions (CastExpr) to the AST.
Params:
stable – The compiler/parser's symbol table/**
     * Type check the children of this node. The type check phase may add
     * coercions (CastExpr) to the AST.
     * @param stable The compiler/parser's symbol table
     */
    public abstract Type typeCheck(SymbolTable stable) throws TypeCheckError;

    
Call typeCheck() on all child syntax tree nodes.
Params:
stable – The compiler/parser's symbol table/**
     * Call typeCheck() on all child syntax tree nodes.
     * @param stable The compiler/parser's symbol table
     */
    protected Type typeCheckContents(SymbolTable stable) throws TypeCheckError {
        for (SyntaxTreeNode item : _contents) {
            item.typeCheck(stable);
        }
        return Type.Void;
    }

    
Translate this abstract syntax tree node into JVM bytecodes.
Params:
classGen – BCEL Java class generator
methodGen – BCEL Java method generator/**
     * Translate this abstract syntax tree node into JVM bytecodes.
     * @param classGen BCEL Java class generator
     * @param methodGen BCEL Java method generator
     */
    public abstract void translate(ClassGenerator classGen,
                                   MethodGenerator methodGen);

    
Call translate() on all child syntax tree nodes.
Params:
classGen – BCEL Java class generator
methodGen – BCEL Java method generator/**
     * Call translate() on all child syntax tree nodes.
     * @param classGen BCEL Java class generator
     * @param methodGen BCEL Java method generator
     */
    protected void translateContents(ClassGenerator classGen,
                                     MethodGenerator methodGen) {
        // Call translate() on all child nodes
        final int n = elementCount();

        for (SyntaxTreeNode item : _contents) {
            methodGen.markChunkStart();
            item.translate(classGen, methodGen);
            methodGen.markChunkEnd();
        }

        // After translation, unmap any registers for any variables/parameters
        // that were declared in this scope. Performing this unmapping in the
        // same AST scope as the declaration deals with the problems of
        // references falling out-of-scope inside the for-each element.
        // (the cause of which being 'lazy' register allocation for references)
        for (int i = 0; i < n; i++) {
            if ( _contents.get(i) instanceof VariableBase) {
                final VariableBase var = (VariableBase)_contents.get(i);
                var.unmapRegister(classGen, methodGen);
            }
        }
    }

    
Checks whether any children of this node is not of the specified type.
Params:
type – the type to be checked against
Returns:
true if there is at least one child that is not of the specified
type, false otherwise./**
     * Checks whether any children of this node is not of the specified type.
     *
     * @param type the type to be checked against
     * @return true if there is at least one child that is not of the specified
     * type, false otherwise.
     */
    public boolean notTypeOf(Class<?> type) {
        if (_contents.size() > 0) {
            for (SyntaxTreeNode item : _contents) {
                if (!item.getClass().isAssignableFrom(type)) {
                    return true;
                }
            }
        }
        return false;
    }

    
Return true if the node represents a simple RTF.
A node is a simple RTF if all children only produce Text value.
Params:
node – A node
Returns:
true if the node content can be considered as a simple RTF./**
     * Return true if the node represents a simple RTF.
     *
     * A node is a simple RTF if all children only produce Text value.
     *
     * @param node A node
     * @return true if the node content can be considered as a simple RTF.
     */
    private boolean isSimpleRTF(SyntaxTreeNode node) {

        List<SyntaxTreeNode> contents = node.getContents();
        if (!contents.stream().noneMatch((item) -> (!isTextElement(item, false)))) {
                return false;
        }

        return true;
    }

     
Return true if the node represents an adaptive RTF.
A node is an adaptive RTF if each children is a Text element
or it is  or .
Params:
node – A node
Returns:
true if the node content can be considered as an adaptive RTF./**
     * Return true if the node represents an adaptive RTF.
     *
     * A node is an adaptive RTF if each children is a Text element
     * or it is <xsl:call-template> or <xsl:apply-templates>.
     *
     * @param node A node
     * @return true if the node content can be considered as an adaptive RTF.
     */
    private boolean isAdaptiveRTF(SyntaxTreeNode node) {

        List<SyntaxTreeNode> contents = node.getContents();
        for (SyntaxTreeNode item : contents) {
            if (!isTextElement(item, true))
                return false;
        }

        return true;
    }

    
Return true if the node only produces Text content.
A node is a Text element if it is Text, xsl:value-of, xsl:number,
or a combination of these nested in a control instruction (xsl:if or
xsl:choose).
If the doExtendedCheck flag is true, xsl:call-template and xsl:apply-templates
are also considered as Text elements.
Params:
node – A node
doExtendedCheck – If this flag is true,  and
 are also considered as Text elements.
Returns:
true if the node of Text type/**
     * Return true if the node only produces Text content.
     *
     * A node is a Text element if it is Text, xsl:value-of, xsl:number,
     * or a combination of these nested in a control instruction (xsl:if or
     * xsl:choose).
     *
     * If the doExtendedCheck flag is true, xsl:call-template and xsl:apply-templates
     * are also considered as Text elements.
     *
     * @param node A node
     * @param doExtendedCheck If this flag is true, <xsl:call-template> and
     * <xsl:apply-templates> are also considered as Text elements.
     *
     * @return true if the node of Text type
     */
    private boolean isTextElement(SyntaxTreeNode node, boolean doExtendedCheck) {
        if (node instanceof ValueOf || node instanceof Number
            || node instanceof Text)
        {
            return true;
        }
        else if (node instanceof If) {
            return doExtendedCheck ? isAdaptiveRTF(node) : isSimpleRTF(node);
        }
        else if (node instanceof Choose) {
            List<SyntaxTreeNode> contents = node.getContents();
            for (SyntaxTreeNode item : contents) {
                if (item instanceof Text ||
                     ((item instanceof When || item instanceof Otherwise)
                     && ((doExtendedCheck && isAdaptiveRTF(item))
                         || (!doExtendedCheck && isSimpleRTF(item)))))
                    continue;
                else
                    return false;
            }
            return true;
        }
        else if (doExtendedCheck &&
                  (node instanceof CallTemplate
                   || node instanceof ApplyTemplates))
            return true;
        else
            return false;
    }

    
Utility method used by parameters and variables to store result trees
Params:
classGen – BCEL Java class generator
methodGen – BCEL Java method generator/**
     * Utility method used by parameters and variables to store result trees
     * @param classGen BCEL Java class generator
     * @param methodGen BCEL Java method generator
     */
    protected void compileResultTree(ClassGenerator classGen,
                                     MethodGenerator methodGen)
    {
        final ConstantPoolGen cpg = classGen.getConstantPool();
        final InstructionList il = methodGen.getInstructionList();
        final Stylesheet stylesheet = classGen.getStylesheet();

        boolean isSimple = isSimpleRTF(this);
        boolean isAdaptive = false;
        if (!isSimple) {
            isAdaptive = isAdaptiveRTF(this);
        }

        int rtfType = isSimple ? DOM.SIMPLE_RTF
                               : (isAdaptive ? DOM.ADAPTIVE_RTF : DOM.TREE_RTF);

        // Save the current handler base on the stack
        il.append(methodGen.loadHandler());

        final String DOM_CLASS = classGen.getDOMClass();

        // Create new instance of DOM class (with RTF_INITIAL_SIZE nodes)
        //int index = cpg.addMethodref(DOM_IMPL, "<init>", "(I)V");
        //il.append(new NEW(cpg.addClass(DOM_IMPL)));

        il.append(methodGen.loadDOM());
        int index = cpg.addInterfaceMethodref(DOM_INTF,
                                 "getResultTreeFrag",
                                 "(IIZ)" + DOM_INTF_SIG);
        il.append(new PUSH(cpg, RTF_INITIAL_SIZE));
        il.append(new PUSH(cpg, rtfType));
        il.append(new PUSH(cpg, stylesheet.callsNodeset()));
        il.append(new INVOKEINTERFACE(index,4));

        il.append(DUP);

        // Overwrite old handler with DOM handler
        index = cpg.addInterfaceMethodref(DOM_INTF,
                                 "getOutputDomBuilder",
                                 "()" + TRANSLET_OUTPUT_SIG);

        il.append(new INVOKEINTERFACE(index,1));
        il.append(DUP);
        il.append(methodGen.storeHandler());

        // Call startDocument on the new handler
        il.append(methodGen.startDocument());

        // Instantiate result tree fragment
        translateContents(classGen, methodGen);

        // Call endDocument on the new handler
        il.append(methodGen.loadHandler());
        il.append(methodGen.endDocument());

        // Check if we need to wrap the DOMImpl object in a DOMAdapter object.
        // DOMAdapter is not needed if the RTF is a simple RTF and the nodeset()
        // function is not used.
        if (stylesheet.callsNodeset()
            && !DOM_CLASS.equals(DOM_IMPL_CLASS)) {
            // new com.sun.org.apache.xalan.internal.xsltc.dom.DOMAdapter(DOMImpl,String[]);
            index = cpg.addMethodref(DOM_ADAPTER_CLASS,
                                     "<init>",
                                     "("+DOM_INTF_SIG+
                                     "["+STRING_SIG+
                                     "["+STRING_SIG+
                                     "[I"+
                                     "["+STRING_SIG+")V");
            il.append(new NEW(cpg.addClass(DOM_ADAPTER_CLASS)));
            il.append(new DUP_X1());
            il.append(SWAP);

            /*
             * Give the DOM adapter an empty type mapping if the nodeset
             * extension function is never called.
             */
            if (!stylesheet.callsNodeset()) {
                il.append(new ICONST(0));
                il.append(new ANEWARRAY(cpg.addClass(STRING)));
                il.append(DUP);
                il.append(DUP);
                il.append(new ICONST(0));
                il.append(new NEWARRAY(BasicType.INT));
                il.append(SWAP);
                il.append(new INVOKESPECIAL(index));
            }
            else {
                // Push name arrays on the stack
                il.append(ALOAD_0);
                il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                                           NAMES_INDEX,
                                           NAMES_INDEX_SIG)));
                il.append(ALOAD_0);
                il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                                           URIS_INDEX,
                                           URIS_INDEX_SIG)));
                il.append(ALOAD_0);
                il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                                           TYPES_INDEX,
                                           TYPES_INDEX_SIG)));
                il.append(ALOAD_0);
                il.append(new GETFIELD(cpg.addFieldref(TRANSLET_CLASS,
                                           NAMESPACE_INDEX,
                                           NAMESPACE_INDEX_SIG)));

                // Initialized DOM adapter
                il.append(new INVOKESPECIAL(index));

                // Add DOM adapter to MultiDOM class by calling addDOMAdapter()
                il.append(DUP);
                il.append(methodGen.loadDOM());
                il.append(new CHECKCAST(cpg.addClass(classGen.getDOMClass())));
                il.append(SWAP);
                index = cpg.addMethodref(MULTI_DOM_CLASS,
                                         "addDOMAdapter",
                                         "(" + DOM_ADAPTER_SIG + ")I");
                il.append(new INVOKEVIRTUAL(index));
                il.append(POP);         // ignore mask returned by addDOMAdapter
            }
        }

        // Restore old handler base from stack
        il.append(SWAP);
        il.append(methodGen.storeHandler());
    }

    
Returns true if this expression/instruction depends on the context. By
default, every expression/instruction depends on the context unless it
overrides this method. Currently used to determine if result trees are
compiled using procedures or little DOMs (result tree fragments).
Returns:
'true' if this node depends on the context./**
     * Returns true if this expression/instruction depends on the context. By
     * default, every expression/instruction depends on the context unless it
     * overrides this method. Currently used to determine if result trees are
     * compiled using procedures or little DOMs (result tree fragments).
     * @return 'true' if this node depends on the context.
     */
    protected boolean contextDependent() {
        return true;
    }

    
Return true if any of the expressions/instructions in the contents of
this node is context dependent.
Returns:
'true' if the contents of this node is context dependent./**
     * Return true if any of the expressions/instructions in the contents of
     * this node is context dependent.
     * @return 'true' if the contents of this node is context dependent.
     */
    protected boolean dependentContents() {
        for (SyntaxTreeNode item : _contents) {
            if (item.contextDependent()) {
                return true;
            }
        }
        return false;
    }

    
Adds a child node to this syntax tree node.
Params:
element – is the new child node./**
     * Adds a child node to this syntax tree node.
     * @param element is the new child node.
     */
    protected final void addElement(SyntaxTreeNode element) {
        _contents.add(element);
        element.setParent(this);
    }

    
Inserts the first child node of this syntax tree node. The existing
children are shifted back one position.
Params:
element – is the new child node./**
     * Inserts the first child node of this syntax tree node. The existing
     * children are shifted back one position.
     * @param element is the new child node.
     */
    protected final void setFirstElement(SyntaxTreeNode element) {
        _contents.add(0, element);
        element.setParent(this);
    }

    
Removed a child node of this syntax tree node.
Params:
element – is the child node to remove./**
     * Removed a child node of this syntax tree node.
     * @param element is the child node to remove.
     */
    protected final void removeElement(SyntaxTreeNode element) {
        _contents.remove(element);
        element.setParent(null);
    }

    
Returns a List containing all the child nodes of this node.
Returns:
A List containing all the child nodes of this node./**
     * Returns a List containing all the child nodes of this node.
     * @return A List containing all the child nodes of this node.
     */
    protected final List<SyntaxTreeNode> getContents() {
        return _contents;
    }

    
Tells you if this node has any child nodes.
Returns:
'true' if this node has any children./**
     * Tells you if this node has any child nodes.
     * @return 'true' if this node has any children.
     */
    protected final boolean hasContents() {
        return elementCount() > 0;
    }

    
Returns the number of children this node has.
Returns:
Number of child nodes./**
     * Returns the number of children this node has.
     * @return Number of child nodes.
     */
    protected final int elementCount() {
        return _contents.size();
    }

    
Returns an Iterator of all child nodes of this node.
Returns:
An Iterator of all child nodes of this node./**
     * Returns an Iterator of all child nodes of this node.
     * @return An Iterator of all child nodes of this node.
     */
    protected final Iterator<SyntaxTreeNode> elements() {
        return _contents.iterator();
    }

    
Returns a child node at a given position.
Params:
pos – The child node's position.
Returns:
The child node./**
     * Returns a child node at a given position.
     * @param pos The child node's position.
     * @return The child node.
     */
    protected final SyntaxTreeNode elementAt(int pos) {
        return _contents.get(pos);
    }

    
Returns this element's last child
Returns:
The child node./**
     * Returns this element's last child
     * @return The child node.
     */
    protected final SyntaxTreeNode lastChild() {
        if (_contents.isEmpty()) return null;
        return _contents.get(_contents.size() - 1);
    }

    
Displays the contents of this syntax tree node (to stdout).
This method is intended for debugging _only_, and should be overridden
by all syntax tree node implementations.
Params:
indent – Indentation level for syntax tree levels./**
     * Displays the contents of this syntax tree node (to stdout).
     * This method is intended for debugging _only_, and should be overridden
     * by all syntax tree node implementations.
     * @param indent Indentation level for syntax tree levels.
     */
    public void display(int indent) {
        displayContents(indent);
    }

    
Displays the contents of this syntax tree node (to stdout).
This method is intended for debugging _only_ !!!
Params:
indent – Indentation level for syntax tree levels./**
     * Displays the contents of this syntax tree node (to stdout).
     * This method is intended for debugging _only_ !!!
     * @param indent Indentation level for syntax tree levels.
     */
    protected void displayContents(int indent) {
        for (SyntaxTreeNode item : _contents) {
            item.display(indent);
        }
    }

    
Set the indentation level for debug output.
Params:
indent – Indentation level for syntax tree levels./**
     * Set the indentation level for debug output.
     * @param indent Indentation level for syntax tree levels.
     */
    protected final void indent(int indent) {
        System.out.print(new String(_spaces, 0, indent));
    }

    
Report an error to the parser.
Params:
element – The element in which the error occured (normally 'this'
but it could also be an expression/pattern/etc.)
parser – The XSLT parser to report the error to.
error – The error code (from util/ErrorMsg).
message – Any additional error message./**
     * Report an error to the parser.
     * @param element The element in which the error occured (normally 'this'
     * but it could also be an expression/pattern/etc.)
     * @param parser The XSLT parser to report the error to.
     * @param error The error code (from util/ErrorMsg).
     * @param message Any additional error message.
     */
    protected void reportError(SyntaxTreeNode element, Parser parser,
                               String errorCode, String message) {
        final ErrorMsg error = new ErrorMsg(errorCode, message, element);
        parser.reportError(Constants.ERROR, error);
    }

    
Report a recoverable error to the parser.
Params:
element – The element in which the error occured (normally 'this'
but it could also be an expression/pattern/etc.)
parser – The XSLT parser to report the error to.
error – The error code (from util/ErrorMsg).
message – Any additional error message./**
     * Report a recoverable error to the parser.
     * @param element The element in which the error occured (normally 'this'
     * but it could also be an expression/pattern/etc.)
     * @param parser The XSLT parser to report the error to.
     * @param error The error code (from util/ErrorMsg).
     * @param message Any additional error message.
     */
    protected  void reportWarning(SyntaxTreeNode element, Parser parser,
                                  String errorCode, String message) {
        final ErrorMsg error = new ErrorMsg(errorCode, message, element);
        parser.reportError(Constants.WARNING, error);
    }

}