xmlexpr.ParseExpToXML Class Reference

Collaboration diagram for xmlexpr.ParseExpToXML:

[legend]List of all members.

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Detailed Description

ParseExpToXML.

The syntax for assignments and expressions in the input string is:

        statement: assignment | addExp

        assignment: ident "=" addExp

        addExp: term | term addOp addExp

        term: unaryExpr | unaryExpr mulOp term

        unaryExpr: factor | minus factor

        factor: ident | number | "(" addExp ")"

Author:

Ian Kaplan, iank@bearcave.com, Jul 5, 2004

Public Member Functions
String	parse (String exp, String topTag, String prefix, String nameSpace, String schemaLoc) throws ExpParseException
Private Member Functions
Element	createElement (String xmlTag)
	Create an DOM Element object.
String	documentToString (Document doc)
Node	factor () throws ExpParseException
	factor: ident | number | "(" expression ")" Exceptions: ExpParseException
Node	unaryExpr () throws ExpParseException
	unaryExpr: factor | minus factor
Node	term () throws ExpParseException
	term: unaryExpr | unaryExpr addOp term Exceptions: ExpParseException
Node	addExp () throws ExpParseException
	addExp: term | term addOp addExp Exceptions: ExpParseException
Node	statement () throws ExpParseException
	statement: assign | expression assign: ident "=" expression; Exceptions: ExpParseException
Private Attributes
Document	mDoc = null
Scanner	mScan = null
String	mNameSpace = null
String	mPrefix = null

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Member Function Documentation

Node xmlexpr.ParseExpToXML.addExp (   )  throws ExpParseException [private]

addExp: term | term addOp addExp Exceptions: ExpParseException  { Node exp = null; Node t = term(); Token op = mScan.getToken(); if (op.getType() == TokenType.MINUS || op.getType() == TokenType.PLUS) { Node rhs = addExp(); Node addOp = createElement( op.getType().getString() ); addOp.appendChild( t ); addOp.appendChild( rhs ); exp = addOp; } else { exp = t; if (op.getType() != TokenType.EOL) { mScan.pushToken( op ); } } return exp; } // addExp

Element xmlexpr.ParseExpToXML.createElement (  String  xmlTag  )  [private]

Create an DOM Element object. If mNameSpace is set then create the Element with a name space, otherwise, create an unqualified Element. { Element elem = null; if (mNameSpace == null) { elem = mDoc.createElement( xmlTag ); } else { if (mPrefix != null) { xmlTag = mPrefix + ":" + xmlTag; } elem = mDoc.createElementNS( mNameSpace, xmlTag ); } return elem; } // createElement

String xmlexpr.ParseExpToXML.documentToString (  Document  doc  )  [private]

{ StringWriter writer = new StringWriter(); OutputFormat out = new OutputFormat(); out.setOmitXMLDeclaration(true); out.setIndenting( true ); out.setIndent( 4 ); out.setLineSeparator(System.getProperty("line.separator")); out.setLineWidth(Integer.MAX_VALUE); XMLSerializer serializer = new XMLSerializer(writer, out); try { Element rootElement = doc.getDocumentElement(); serializer.serialize(rootElement); } catch (IOException e) { System.out.println("ParseExpToXML::documentToString: IOException = " + e ); } return writer.toString(); } // documentToString

Node xmlexpr.ParseExpToXML.factor (   )  throws ExpParseException [private]

factor: ident | number | "(" expression ")" Exceptions: ExpParseException  { final String msg = "identifier, number or ( exp ) expected"; Node fact = null; Token f = mScan.getToken(); String errMsg = null; if (f != null) { if (f.getType() == TokenType.IDENT || f.getType() == TokenType.INT) { if (f.getType() == TokenType.INT) { fact = createElement( TokenType.INT.getString() ); } else { fact = createElement( TokenType.IDENT.getString() ); } Text txt = mDoc.createTextNode( f.getString() ); fact.appendChild( txt ); } else if (f.getType() == TokenType.LPAREN) { fact = addExp(); f = mScan.getToken(); if (f == null || f.getType() != TokenType.RPAREN) { errMsg = "\")\" expected"; } else { Node top = createElement( TokenType.PAREN.getString() ); top.appendChild( fact ); fact = top; } } else { errMsg = msg; } } else { errMsg = msg; } if (errMsg != null) { throw new ExpParseException( errMsg ); } return fact; } // factor

String xmlexpr.ParseExpToXML.parse (  String  exp, String  topTag, String  prefix, String  nameSpace, String  schemaLoc )  throws ExpParseException

{ mDoc = DocumentFactory.newDocument( topTag, prefix, nameSpace, schemaLoc ); mPrefix = prefix; mNameSpace = nameSpace; mScan = new Scanner( exp ); Node root = (Node)mDoc.getDocumentElement(); Node child = statement(); if (child != null) { root.appendChild( child ); } String xml = documentToString( mDoc ); return xml; } // parse

Node xmlexpr.ParseExpToXML.statement (   )  throws ExpParseException [private]

statement: assign | expression assign: ident "=" expression; Exceptions: ExpParseException  { String errMsg = null; Node stmt = null; Node lhs = addExp(); Token t = mScan.getToken(); if (mScan.isEOL()) { stmt = lhs; } else if (t.getType() == TokenType.EQUAL) { if (lhs.getLocalName().equals(TokenType.IDENT.getString())) { Node rhs = addExp(); Node equals = (Node)createElement( t.getType().getString() ); equals.appendChild( lhs ); equals.appendChild( rhs ); stmt = equals; t = mScan.getToken(); if (t.getType() != TokenType.EOL) { errMsg = "Syntax error: badly formed expression"; } } else { errMsg = "LHS identifier expected"; } } else { errMsg = "\"=\" expected"; } if (errMsg != null) { throw new ExpParseException( errMsg ); } return stmt; } // statement

Node xmlexpr.ParseExpToXML.term (   )  throws ExpParseException [private]

term: unaryExpr | unaryExpr addOp term Exceptions: ExpParseException  { Node exp = null; Node t = unaryExpr(); // either unaryExp or the LHS of the sub-expression Token op = mScan.getToken(); if (op.getType() == TokenType.TIMES || op.getType() == TokenType.DIV || op.getType() == TokenType.MOD) { Node rhs = term(); Node mulOp = createElement( op.getType().getString() ); mulOp.appendChild( t ); mulOp.appendChild( rhs ); exp = mulOp; } else { exp = t; if (op.getType() != TokenType.EOL) { mScan.pushToken( op ); } } return exp; } // term

Node xmlexpr.ParseExpToXML.unaryExpr (   )  throws ExpParseException [private]

unaryExpr: factor | minus factor { boolean unaryMinus = false; Token t = mScan.getToken(); if (t.getType() == TokenType.MINUS) { unaryMinus = true; } else { mScan.pushToken( t ); } Node top = factor(); if (unaryMinus) { Node minus = createElement( TokenType.UMINUS.getString() ); minus.appendChild( top ); top = minus; } return top; } // unaryExpr

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Member Data Documentation

Document xmlexpr.ParseExpToXML.mDoc = null [private]

String xmlexpr.ParseExpToXML.mNameSpace = null [private]

String xmlexpr.ParseExpToXML.mPrefix = null [private]

Scanner xmlexpr.ParseExpToXML.mScan = null [private]

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The documentation for this class was generated from the following file:

• ParseExpToXML.java

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