bundles/org.eclipse.jst.jsp.core/src/org/eclipse/jst/jsp/core/internal/java/jspel/ELGeneratorVisitor.java - sourceediting/webtools.sourceediting - Git at Google

 /*******************************************************************************
  * Copyright (c) 2005 BEA Systems and others.
  * 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:
  *     BEA Systems - initial implementation
  *
  *******************************************************************************/
 package org.eclipse.jst.jsp.core.internal.java.jspel;

 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;

 import org.eclipse.jface.text.Position;
 import org.eclipse.jst.jsp.core.internal.contentmodel.TaglibController;
 import org.eclipse.jst.jsp.core.internal.contentmodel.tld.CMDocumentImpl;
 import org.eclipse.jst.jsp.core.internal.contentmodel.tld.TLDCMDocumentManager;
 import org.eclipse.jst.jsp.core.internal.contentmodel.tld.TaglibTracker;
 import org.eclipse.jst.jsp.core.internal.contentmodel.tld.provisional.TLDFunction;
 import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocument;
 import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
 import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegionCollection;

 public class ELGeneratorVisitor implements JSPELParserVisitor {

 	private static final String ENDL = "\n"; //$NON-NLS-1$

 	private static final String fExpressionHeader1 = "public String _elExpression"; //$NON-NLS-1$
 	private static final String fExpressionHeader2 = "()" + ENDL + //$NON-NLS-1$
 	"\t\tthrows java.io.IOException, javax.servlet.ServletException {" + ENDL + //$NON-NLS-1$
 	"javax.servlet.jsp.PageContext pageContext = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map param = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map paramValues = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map header = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map headerValues = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map cookie = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map initParam = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map pageScope = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map requestScope = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map sessionScope = null;" + ENDL + //$NON-NLS-1$
 	"java.util.Map applicationScope = null;" + ENDL + //$NON-NLS-1$
 	"return \"\"+"; //$NON-NLS-1$

 	private static final String fJspImplicitObjects[] = { "pageContext" }; //$NON-NLS-1$

 	private static final String fJspImplicitMaps[] = { 	"param", "paramValues", "header", "headerValues", //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
 														"cookie", "initParam", "pageScope", "requestScope", "sessionScope",  //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$
 														"applicationScope" }; //$NON-NLS-1$

 	private static final HashMap fJSPImplicitObjectMap = new HashMap(fJspImplicitObjects.length);
 	static {
 		for(int i = 0; i < fJspImplicitObjects.length; i++) {
 			fJSPImplicitObjectMap.put(fJspImplicitObjects[i], new Boolean(true));
 		}

 		for(int i = 0; i < fJspImplicitMaps.length; i++) {
 			fJSPImplicitObjectMap.put(fJspImplicitMaps[i], new Boolean(false));
 		}
 	}

 	private static final String fFooter = " ;" + ENDL + "}" + ENDL; //$NON-NLS-1$ //$NON-NLS-2$

 	private StringBuffer fResult;
 	private Map fCodeMap;
 	private int fOffsetInUserCode;
 	private static int methodCounter = 0;
 	private IStructuredDocument fDocument = null;
 	private int fContentStart;
 	private static Map fOperatorMap;

 	// this flag lets us know if we were unable to generate for some reason.  One possible reason is that the expression
 	// contains a reference to a variable for which information is only available at runtime.
 	private boolean fCanGenerate = true;

 	private IStructuredDocumentRegion fCurrentNode;

 	/**
 	 * Tranlsation of XML-style operators to java
 	 */
 	static {
 		fOperatorMap = new HashMap();
 		fOperatorMap.put("gt", ">"); //$NON-NLS-1$ //$NON-NLS-2$
 		fOperatorMap.put("lt", "<"); //$NON-NLS-1$ //$NON-NLS-2$
 		fOperatorMap.put("ge", ">="); //$NON-NLS-1$ //$NON-NLS-2$
 		fOperatorMap.put("le", "<="); //$NON-NLS-1$ //$NON-NLS-2$
 		fOperatorMap.put("mod", "%"); //$NON-NLS-1$ //$NON-NLS-2$
 		fOperatorMap.put("eq", "=="); //$NON-NLS-1$ //$NON-NLS-2$
 	}

 	/**
 	 * The constructor squirrels away a few things we'll need later
 	 *
 	 * @param result
 	 * @param codeMap
 	 * @param translator
 	 * @param jspReferenceRegion
 	 * @param contentStart
 	 */
 	public ELGeneratorVisitor(StringBuffer result, IStructuredDocumentRegion currentNode, Map codeMap, IStructuredDocument document, ITextRegionCollection jspReferenceRegion, int contentStart)
 	{
 		fResult = result;
 		fCodeMap = codeMap;
 		fOffsetInUserCode = result.length();
 		fContentStart = contentStart;
 		fDocument = document;
 		fCurrentNode = currentNode;
 	}

 	/**
 	 * Append a token to the output stream.  Automatically calculating mapping.
 	 *
 	 * @param token
 	 */
 	private void append(Token token)
 	{
 		append(token.image, token.beginColumn - 1, token.endColumn);
 	}

 	/**
 	 * Append a translation for the corresponding input token.
 	 *
 	 * @param translated
 	 * @param token
 	 */
 	private void append(String translated, Token token)
 	{
 		append(translated, token.beginColumn - 1, token.endColumn);
 	}

 	/**
 	 * Append a string explicitly giving the input mapping.
 	 *
 	 * @param newText
 	 * @param jspPositionStart
 	 * @param jspPositionEnd
 	 */
 	private void append(String newText, int jspPositionStart, int jspPositionEnd)
 	{
 		fResult.append(newText);
 		Position javaRange = new Position(fOffsetInUserCode, newText.length());
 		Position jspRange = new Position(fContentStart + jspPositionStart, jspPositionEnd - jspPositionStart);

 		fCodeMap.put(javaRange, jspRange);
 		fOffsetInUserCode += newText.length();
 	}

 	/**
 	 * Append text that will be unmapped and therefore will not be available for completion.
 	 *
 	 * @param newText
 	 */
 	private void append(String newText)
 	{
 		fResult.append(newText);
 		fOffsetInUserCode += newText.length();
 	}

 	/**
 	 * Generate a function invocation.
 	 *
 	 * @param fullFunctionName
 	 * @return
 	 */
 	protected String genFunction(String fullFunctionName) {
 		TLDCMDocumentManager docMgr = TaglibController.getTLDCMDocumentManager(fDocument);
 		int colonIndex = fullFunctionName.indexOf(':');
 		String prefix = fullFunctionName.substring(0, colonIndex);
 		String functionName = fullFunctionName.substring(colonIndex + 1);
 		if (docMgr == null)
 			return null;

 		Iterator taglibs = docMgr.getCMDocumentTrackers(fCurrentNode.getStartOffset()).iterator();
 		while (taglibs.hasNext()) {
 			TaglibTracker tracker = (TaglibTracker)taglibs.next();
 			if(tracker.getPrefix().equals(prefix)) {
 				CMDocumentImpl doc = (CMDocumentImpl)tracker.getDocument();

 				List functions = doc.getFunctions();
 				for(Iterator it = functions.iterator(); it.hasNext(); ) {
 					TLDFunction function = (TLDFunction)it.next();
 					if(function.getName().equals(functionName)) {
 						return function.getClassName() + "." + function.getName(); //$NON-NLS-1$
 					}
 				}
 			}
 		}
 		return null;
 	}

 	/**
 	 * Handle a simple node -- fallback
 	 */
 	public Object visit(SimpleNode node, Object data) {
 		return(node.childrenAccept(this, data));
 	}

 	static synchronized int getMethodCounter() {
 		return methodCounter++;
 	}

 	/**
 	 * Handle top-level expression
 	 */
 	public Object visit(ASTExpression node, Object data) {
 		int start = node.getFirstToken().beginColumn - 1;
 		int end = node.lastToken.endColumn - 1;
 		append(fExpressionHeader1, start, start);
 		append(Integer.toString(getMethodCounter()), start, start);
 		append(fExpressionHeader2, start, start);

 		Object retval = node.childrenAccept(this, data);

 		append(fFooter, end, end);

 		// something is preventing good code generation so empty out the result and the map.
 		if(!fCanGenerate) {
 			fResult.delete(0, fResult.length());
 			fCodeMap.clear();
 		}
 		return retval;
 	}

 	/**
 	 * Generically generate an operator node.
 	 *
 	 * @param node
 	 * @param data
 	 */
 	private void generateOperatorNode(ASTOperatorExpression node, Object data) {
 		for(int i = 0; i < node.children.length; i++) {
 			node.children[i].jjtAccept(this, data);
 			if( node.children.length - i > 1) {
 				appendOperator((Token)node.getOperatorTokens().get(i));
 			}
 		}
 	}

 	/**
 	 * Append an operator to the output stream after translation (if any)
 	 *
 	 * @param token
 	 * @return
 	 */
 	private String appendOperator(Token token) {
 		String tokenImage = token.image.trim();
 		String translated = (String)fOperatorMap.get(tokenImage);
 		if(null != translated) {
 			append(translated, token);
 		} else {
 			append(token);
 		}
 		return(translated);
 	}

 	/**
 	 * Handle or Expression
 	 */
 	public Object visit(ASTOrExpression node, Object data) {
 		generateOperatorNode(node, data);
 		return(null);
 	}


 	/**
 	 * Handle and expression
 	 */
 	public Object visit(ASTAndExpression node, Object data) {
 		generateOperatorNode(node, data);
 		return(null);
 	}


 	/**
 	 * Handle equality
 	 */
 	public Object visit(ASTEqualityExpression node, Object data) {
 		generateOperatorNode(node, data);
 		return(null);
 	}


 	/**
 	 * Handle Relational
 	 */
 	public Object visit(ASTRelationalExpression node, Object data) {
 		generateOperatorNode(node, data);
 		return(null);
 	}


 	/**
 	 * Handle addition
 	 */
 	public Object visit(ASTAddExpression node, Object data) {
 		generateOperatorNode(node, data);
 		return(null);
 	}


 	/**
 	 * Handle multiply
 	 */
 	public Object visit(ASTMultiplyExpression node, Object data) {
 		generateOperatorNode(node, data);
 		return(null);
 	}


 	/**
 	 * Choice Expression (ternary operator)
 	 */
 	public Object visit(ASTChoiceExpression node, Object data) {
 		node.children[0].jjtAccept(this, data);
 		append("?"); //$NON-NLS-1$
 		node.children[1].jjtAccept(this, data);
 		append(":"); //$NON-NLS-1$
 		node.children[2].jjtAccept(this,data);
 		return null;
 	}


 	/**
 	 * Handle unary
 	 */
 	public Object visit(ASTUnaryExpression node, Object data) {
 		if(JSPELParserConstants.EMPTY == node.firstToken.kind) {
 			append("((null == "); //$NON-NLS-1$
 			node.childrenAccept(this, data);
 			append(") || ("); //$NON-NLS-1$
 			node.childrenAccept(this, data);
 			append(").isEmpty())"); //$NON-NLS-1$
 		} else if(JSPELParserConstants.NOT1 == node.firstToken.kind || JSPELParserConstants.NOT2 == node.firstToken.kind) {
 			append("(!"); //$NON-NLS-1$
 			node.childrenAccept(this, data);
 			append(")"); //$NON-NLS-1$
 		} else if(JSPELParserConstants.MINUS == node.firstToken.kind) {
 			append("(-"); //$NON-NLS-1$
 			node.childrenAccept(this, data);
 			append(")"); //$NON-NLS-1$
 		} else {
 			node.childrenAccept(this, data);
 		}
 		return null;
 	}


 	/**
 	 * Value node
 	 */
 	public Object visit(ASTValue node, Object data) {
 		if(node.jjtGetNumChildren() >= 2) {
 			if(node.jjtGetChild(0) instanceof ASTValuePrefix && node.jjtGetChild(1) instanceof ASTValueSuffix) {
 				ASTValuePrefix prefix = (ASTValuePrefix) node.jjtGetChild(0);
 				ASTValueSuffix suffix = (ASTValueSuffix) node.jjtGetChild(1);
 				if(prefix.firstToken.image.equals("pageContext") && suffix.getPropertyNameToken().image.equals("request")) {
 					append("((HTTPServletRequest)");
 				}
 			}
 		}
 		return node.childrenAccept(this, data);
 	}


 	/**
 	 * Value Prefix
 	 */
 	public Object visit(ASTValuePrefix node, Object data) {
 		// this is a raw identifier.  May sure it's an implicit object.
 		// This is the primary plae where modification is needed to
 		// support JSF backing beans.
 		if(null == node.children) {
 			if(isCompletingObject(node.firstToken.image)) {
 				append(node.firstToken);
 			} else {
 				fCanGenerate = false;
 			}
 			return(null);
 		}
 		return node.childrenAccept(this, data);
 	}


 	/**
 	 * Function for testing implicit objects.
 	 *
 	 * @param image
 	 * @return
 	 */
 	private boolean isCompletingObject(String image) {
 		Boolean value = (Boolean)fJSPImplicitObjectMap.get(image);
 		return null == value ? false : value.booleanValue();
 	}

 	/**
 	 * Value suffix
 	 */
 	public Object visit(ASTValueSuffix node, Object data) {
 		if(JSPELParserConstants.LBRACKET == node.firstToken.kind) {
 			fCanGenerate = false;
 		} else if(null != node.getPropertyNameToken()) {
 			Token suffix = node.getPropertyNameToken();
 			String ucaseName = suffix.image.substring(0, 1).toUpperCase() + suffix.image.substring(1, suffix.image.length());

 			// This is a special case.  Note that the type system, no matter how much type information
 			// we would have wouldn't give us the correct result.  We're looking for "pageContext.request"
 			// here and will add a downcast to (HTTPServletRequest)

 			append(node.firstToken);
 			append("get" + ucaseName + "()", suffix); //$NON-NLS-1$ //$NON-NLS-2$

 			SimpleNode parent = (SimpleNode) node.jjtGetParent();
 			if(suffix.image.equals("request") && parent instanceof ASTValue && //$NON-NLS-1$
 					parent.jjtGetParent() instanceof ASTUnaryExpression && parent.firstToken.image.equals("pageContext")) { //$NON-NLS-1$
 				append(")");
 			}


 		} else {
 			append(node.firstToken);
 		}
 		return null;
 	}


 	/**
 	 * Function invocation
 	 */
 	public Object visit(ASTFunctionInvocation node, Object data) {
 		String functionTranslation = genFunction(node.getFullFunctionName());
 		if(null != functionTranslation)
 		{
 			append(functionTranslation + "(", node.getFirstToken()); //$NON-NLS-1$
 			for(int i = 0; i < node.children.length; i++) {
 				node.children[i].jjtAccept(this, data);
 				if( node.children.length - i > 1){
 					append(","); //$NON-NLS-1$
 				}
 			}
 			append(")"); //$NON-NLS-1$
 		}
 		return null;
 	}

 	/**
 	 * Literal
 	 */
 	public Object visit(ASTLiteral node, Object data) {
 		// TODO any further translation needed?
 		append(node.firstToken);
 		return null;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2005 BEA Systems and others.
	* 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:
	* BEA Systems - initial implementation
	*
	*******************************************************************************/
	package org.eclipse.jst.jsp.core.internal.java.jspel;

	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.List;
	import java.util.Map;

	import org.eclipse.jface.text.Position;
	import org.eclipse.jst.jsp.core.internal.contentmodel.TaglibController;
	import org.eclipse.jst.jsp.core.internal.contentmodel.tld.CMDocumentImpl;
	import org.eclipse.jst.jsp.core.internal.contentmodel.tld.TLDCMDocumentManager;
	import org.eclipse.jst.jsp.core.internal.contentmodel.tld.TaglibTracker;
	import org.eclipse.jst.jsp.core.internal.contentmodel.tld.provisional.TLDFunction;
	import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocument;
	import org.eclipse.wst.sse.core.internal.provisional.text.IStructuredDocumentRegion;
	import org.eclipse.wst.sse.core.internal.provisional.text.ITextRegionCollection;

	public class ELGeneratorVisitor implements JSPELParserVisitor {

	private static final String ENDL = "\n"; //$NON-NLS-1$

	private static final String fExpressionHeader1 = "public String _elExpression"; //$NON-NLS-1$
	private static final String fExpressionHeader2 = "()" + ENDL + //$NON-NLS-1$
	"\t\tthrows java.io.IOException, javax.servlet.ServletException {" + ENDL + //$NON-NLS-1$
	"javax.servlet.jsp.PageContext pageContext = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map param = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map paramValues = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map header = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map headerValues = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map cookie = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map initParam = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map pageScope = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map requestScope = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map sessionScope = null;" + ENDL + //$NON-NLS-1$
	"java.util.Map applicationScope = null;" + ENDL + //$NON-NLS-1$
	"return \"\"+"; //$NON-NLS-1$

	private static final String fJspImplicitObjects[] = { "pageContext" }; //$NON-NLS-1$

	private static final String fJspImplicitMaps[] = { "param", "paramValues", "header", "headerValues", //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$
	"cookie", "initParam", "pageScope", "requestScope", "sessionScope", //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$ //$NON-NLS-4$ //$NON-NLS-5$
	"applicationScope" }; //$NON-NLS-1$

	private static final HashMap fJSPImplicitObjectMap = new HashMap(fJspImplicitObjects.length);
	static {
	for(int i = 0; i < fJspImplicitObjects.length; i++) {
	fJSPImplicitObjectMap.put(fJspImplicitObjects[i], new Boolean(true));
	}

	for(int i = 0; i < fJspImplicitMaps.length; i++) {
	fJSPImplicitObjectMap.put(fJspImplicitMaps[i], new Boolean(false));
	}
	}

	private static final String fFooter = " ;" + ENDL + "}" + ENDL; //$NON-NLS-1$ //$NON-NLS-2$

	private StringBuffer fResult;
	private Map fCodeMap;
	private int fOffsetInUserCode;
	private static int methodCounter = 0;
	private IStructuredDocument fDocument = null;
	private int fContentStart;
	private static Map fOperatorMap;

	// this flag lets us know if we were unable to generate for some reason. One possible reason is that the expression
	// contains a reference to a variable for which information is only available at runtime.
	private boolean fCanGenerate = true;

	private IStructuredDocumentRegion fCurrentNode;

	/**
	* Tranlsation of XML-style operators to java
	*/
	static {
	fOperatorMap = new HashMap();
	fOperatorMap.put("gt", ">"); //$NON-NLS-1$ //$NON-NLS-2$
	fOperatorMap.put("lt", "<"); //$NON-NLS-1$ //$NON-NLS-2$
	fOperatorMap.put("ge", ">="); //$NON-NLS-1$ //$NON-NLS-2$
	fOperatorMap.put("le", "<="); //$NON-NLS-1$ //$NON-NLS-2$
	fOperatorMap.put("mod", "%"); //$NON-NLS-1$ //$NON-NLS-2$
	fOperatorMap.put("eq", "=="); //$NON-NLS-1$ //$NON-NLS-2$
	}

	/**
	* The constructor squirrels away a few things we'll need later
	*
	* @param result
	* @param codeMap
	* @param translator
	* @param jspReferenceRegion
	* @param contentStart
	*/
	public ELGeneratorVisitor(StringBuffer result, IStructuredDocumentRegion currentNode, Map codeMap, IStructuredDocument document, ITextRegionCollection jspReferenceRegion, int contentStart)
	{
	fResult = result;
	fCodeMap = codeMap;
	fOffsetInUserCode = result.length();
	fContentStart = contentStart;
	fDocument = document;
	fCurrentNode = currentNode;
	}

	/**
	* Append a token to the output stream. Automatically calculating mapping.
	*
	* @param token
	*/
	private void append(Token token)
	{
	append(token.image, token.beginColumn - 1, token.endColumn);
	}

	/**
	* Append a translation for the corresponding input token.
	*
	* @param translated
	* @param token
	*/
	private void append(String translated, Token token)
	{
	append(translated, token.beginColumn - 1, token.endColumn);
	}

	/**
	* Append a string explicitly giving the input mapping.
	*
	* @param newText
	* @param jspPositionStart
	* @param jspPositionEnd
	*/
	private void append(String newText, int jspPositionStart, int jspPositionEnd)
	{
	fResult.append(newText);
	Position javaRange = new Position(fOffsetInUserCode, newText.length());
	Position jspRange = new Position(fContentStart + jspPositionStart, jspPositionEnd - jspPositionStart);

	fCodeMap.put(javaRange, jspRange);
	fOffsetInUserCode += newText.length();
	}

	/**
	* Append text that will be unmapped and therefore will not be available for completion.
	*
	* @param newText
	*/
	private void append(String newText)
	{
	fResult.append(newText);
	fOffsetInUserCode += newText.length();
	}

	/**
	* Generate a function invocation.
	*
	* @param fullFunctionName
	* @return
	*/
	protected String genFunction(String fullFunctionName) {
	TLDCMDocumentManager docMgr = TaglibController.getTLDCMDocumentManager(fDocument);
	int colonIndex = fullFunctionName.indexOf(':');
	String prefix = fullFunctionName.substring(0, colonIndex);
	String functionName = fullFunctionName.substring(colonIndex + 1);
	if (docMgr == null)
	return null;

	Iterator taglibs = docMgr.getCMDocumentTrackers(fCurrentNode.getStartOffset()).iterator();
	while (taglibs.hasNext()) {
	TaglibTracker tracker = (TaglibTracker)taglibs.next();
	if(tracker.getPrefix().equals(prefix)) {
	CMDocumentImpl doc = (CMDocumentImpl)tracker.getDocument();

	List functions = doc.getFunctions();
	for(Iterator it = functions.iterator(); it.hasNext(); ) {
	TLDFunction function = (TLDFunction)it.next();
	if(function.getName().equals(functionName)) {
	return function.getClassName() + "." + function.getName(); //$NON-NLS-1$
	}
	}
	}
	}
	return null;
	}

	/**
	* Handle a simple node -- fallback
	*/
	public Object visit(SimpleNode node, Object data) {
	return(node.childrenAccept(this, data));
	}

	static synchronized int getMethodCounter() {
	return methodCounter++;
	}

	/**
	* Handle top-level expression
	*/
	public Object visit(ASTExpression node, Object data) {
	int start = node.getFirstToken().beginColumn - 1;
	int end = node.lastToken.endColumn - 1;
	append(fExpressionHeader1, start, start);
	append(Integer.toString(getMethodCounter()), start, start);
	append(fExpressionHeader2, start, start);

	Object retval = node.childrenAccept(this, data);

	append(fFooter, end, end);

	// something is preventing good code generation so empty out the result and the map.
	if(!fCanGenerate) {
	fResult.delete(0, fResult.length());
	fCodeMap.clear();
	}
	return retval;
	}

	/**
	* Generically generate an operator node.
	*
	* @param node
	* @param data
	*/
	private void generateOperatorNode(ASTOperatorExpression node, Object data) {
	for(int i = 0; i < node.children.length; i++) {
	node.children[i].jjtAccept(this, data);
	if( node.children.length - i > 1) {
	appendOperator((Token)node.getOperatorTokens().get(i));
	}
	}
	}

	/**
	* Append an operator to the output stream after translation (if any)
	*
	* @param token
	* @return
	*/
	private String appendOperator(Token token) {
	String tokenImage = token.image.trim();
	String translated = (String)fOperatorMap.get(tokenImage);
	if(null != translated) {
	append(translated, token);
	} else {
	append(token);
	}
	return(translated);
	}

	/**
	* Handle or Expression
	*/
	public Object visit(ASTOrExpression node, Object data) {
	generateOperatorNode(node, data);
	return(null);
	}


	/**
	* Handle and expression
	*/
	public Object visit(ASTAndExpression node, Object data) {
	generateOperatorNode(node, data);
	return(null);
	}


	/**
	* Handle equality
	*/
	public Object visit(ASTEqualityExpression node, Object data) {
	generateOperatorNode(node, data);
	return(null);
	}


	/**
	* Handle Relational
	*/
	public Object visit(ASTRelationalExpression node, Object data) {
	generateOperatorNode(node, data);
	return(null);
	}


	/**
	* Handle addition
	*/
	public Object visit(ASTAddExpression node, Object data) {
	generateOperatorNode(node, data);
	return(null);
	}


	/**
	* Handle multiply
	*/
	public Object visit(ASTMultiplyExpression node, Object data) {
	generateOperatorNode(node, data);
	return(null);
	}


	/**
	* Choice Expression (ternary operator)
	*/
	public Object visit(ASTChoiceExpression node, Object data) {
	node.children[0].jjtAccept(this, data);
	append("?"); //$NON-NLS-1$
	node.children[1].jjtAccept(this, data);
	append(":"); //$NON-NLS-1$
	node.children[2].jjtAccept(this,data);
	return null;
	}


	/**
	* Handle unary
	*/
	public Object visit(ASTUnaryExpression node, Object data) {
	if(JSPELParserConstants.EMPTY == node.firstToken.kind) {
	append("((null == "); //$NON-NLS-1$
	node.childrenAccept(this, data);
	append(") \|\| ("); //$NON-NLS-1$
	node.childrenAccept(this, data);
	append(").isEmpty())"); //$NON-NLS-1$
	} else if(JSPELParserConstants.NOT1 == node.firstToken.kind \|\| JSPELParserConstants.NOT2 == node.firstToken.kind) {
	append("(!"); //$NON-NLS-1$
	node.childrenAccept(this, data);
	append(")"); //$NON-NLS-1$
	} else if(JSPELParserConstants.MINUS == node.firstToken.kind) {
	append("(-"); //$NON-NLS-1$
	node.childrenAccept(this, data);
	append(")"); //$NON-NLS-1$
	} else {
	node.childrenAccept(this, data);
	}
	return null;
	}


	/**
	* Value node
	*/
	public Object visit(ASTValue node, Object data) {
	if(node.jjtGetNumChildren() >= 2) {
	if(node.jjtGetChild(0) instanceof ASTValuePrefix && node.jjtGetChild(1) instanceof ASTValueSuffix) {
	ASTValuePrefix prefix = (ASTValuePrefix) node.jjtGetChild(0);
	ASTValueSuffix suffix = (ASTValueSuffix) node.jjtGetChild(1);
	if(prefix.firstToken.image.equals("pageContext") && suffix.getPropertyNameToken().image.equals("request")) {
	append("((HTTPServletRequest)");
	}
	}
	}
	return node.childrenAccept(this, data);
	}


	/**
	* Value Prefix
	*/
	public Object visit(ASTValuePrefix node, Object data) {
	// this is a raw identifier. May sure it's an implicit object.
	// This is the primary plae where modification is needed to
	// support JSF backing beans.
	if(null == node.children) {
	if(isCompletingObject(node.firstToken.image)) {
	append(node.firstToken);
	} else {
	fCanGenerate = false;
	}
	return(null);
	}
	return node.childrenAccept(this, data);
	}


	/**
	* Function for testing implicit objects.
	*
	* @param image
	* @return
	*/
	private boolean isCompletingObject(String image) {
	Boolean value = (Boolean)fJSPImplicitObjectMap.get(image);
	return null == value ? false : value.booleanValue();
	}

	/**
	* Value suffix
	*/
	public Object visit(ASTValueSuffix node, Object data) {
	if(JSPELParserConstants.LBRACKET == node.firstToken.kind) {
	fCanGenerate = false;
	} else if(null != node.getPropertyNameToken()) {
	Token suffix = node.getPropertyNameToken();
	String ucaseName = suffix.image.substring(0, 1).toUpperCase() + suffix.image.substring(1, suffix.image.length());

	// This is a special case. Note that the type system, no matter how much type information
	// we would have wouldn't give us the correct result. We're looking for "pageContext.request"
	// here and will add a downcast to (HTTPServletRequest)

	append(node.firstToken);
	append("get" + ucaseName + "()", suffix); //$NON-NLS-1$ //$NON-NLS-2$

	SimpleNode parent = (SimpleNode) node.jjtGetParent();
	if(suffix.image.equals("request") && parent instanceof ASTValue && //$NON-NLS-1$
	parent.jjtGetParent() instanceof ASTUnaryExpression && parent.firstToken.image.equals("pageContext")) { //$NON-NLS-1$
	append(")");
	}


	} else {
	append(node.firstToken);
	}
	return null;
	}


	/**
	* Function invocation
	*/
	public Object visit(ASTFunctionInvocation node, Object data) {
	String functionTranslation = genFunction(node.getFullFunctionName());
	if(null != functionTranslation)
	{
	append(functionTranslation + "(", node.getFirstToken()); //$NON-NLS-1$
	for(int i = 0; i < node.children.length; i++) {
	node.children[i].jjtAccept(this, data);
	if( node.children.length - i > 1){
	append(","); //$NON-NLS-1$
	}
	}
	append(")"); //$NON-NLS-1$
	}
	return null;
	}

	/**
	* Literal
	*/
	public Object visit(ASTLiteral node, Object data) {
	// TODO any further translation needed?
	append(node.firstToken);
	return null;
	}
	}