Package org.camunda.bpm.engine.impl.juel

Class Parser

java.lang.Object

org.camunda.bpm.engine.impl.juel.Parser

public class Parser
extends Object

Handcrafted top-down parser.

Author:

Christoph Beck

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Parser.ExtensionHandler	Provide limited support for syntax extensions.
static class	Parser.ExtensionPoint
static class	Parser.ParseException	Parse exception type

Field Summary

Fields

Modifier and Type	Field	Description
protected Builder	context
protected Map<Scanner.ExtensionToken,Parser.ExtensionHandler>	extensions
protected Scanner	scanner

Constructor Summary

Constructors

Constructor	Description
Parser(Builder context, String input)

Method Summary

Modifier and Type	Method	Description
protected AstNode	add(boolean required)	add := add (<PLUS> mul | <MINUS> mul)*
protected AstNode	and(boolean required)	and := eq (<AND> eq)*
protected AstNode	cmp(boolean required)	cmp := add (<LT> add | <LE> add | <GE> add | <GT> add)*
protected Scanner.Token	consumeToken()	consume current token (get next token).
protected Scanner.Token	consumeToken(Scanner.Symbol expected)	consume current token (get next token); throw exception if the current token doesn't match the expected symbol.
protected AstBinary	createAstBinary(AstNode left, AstNode right, AstBinary.Operator operator)
protected AstBracket	createAstBracket(AstNode base, AstNode property, boolean lvalue, boolean strict)
protected AstChoice	createAstChoice(AstNode question, AstNode yes, AstNode no)
protected AstComposite	createAstComposite(List<AstNode> nodes)
protected AstDot	createAstDot(AstNode base, String property, boolean lvalue)
protected AstFunction	createAstFunction(String name, int index, AstParameters params)
protected AstIdentifier	createAstIdentifier(String name, int index)
protected AstMethod	createAstMethod(AstProperty property, AstParameters params)
protected AstUnary	createAstUnary(AstNode child, AstUnary.Operator operator)
protected Scanner	createScanner(String expression)
protected AstNode	eq(boolean required)	eq := cmp (<EQ> cmp | <NE> cmp)*
protected AstEval	eval()	eval := dynamic | deferred
protected AstEval	eval(boolean required, boolean deferred)	dynmamic := <START_EVAL_DYNAMIC> expr <END_EVAL> deferred := <START_EVAL_DEFERRED> expr <END_EVAL>
protected AstNode	expr(boolean required)	expr := or (<QUESTION> expr <COLON> expr)?
protected void	fail(String expected)	throw exception
protected void	fail(Scanner.Symbol expected)	throw exception
protected AstFunction	function(String name, AstParameters params)
protected Parser.ExtensionHandler	getExtensionHandler(Scanner.Token token)
protected List<FunctionNode>	getFunctions()
protected List<IdentifierNode>	getIdentifiers()
protected Scanner.Token	getToken()
protected AstIdentifier	identifier(String name)
protected AstNode	literal()	literal := <TRUE> | <FALSE> | <STRING> | <INTEGER> | <FLOAT> | <NULL>
protected Scanner.Token	lookahead(int index)	get lookahead symbol.
protected AstNode	mul(boolean required)	mul := unary (<MUL> unary | <DIV> unary | <MOD> unary)*
protected AstNode	nonliteral()	nonliteral := <IDENTIFIER> | function | <LPAREN> expr <RPAREN> function := (<IDENTIFIER> <COLON>)? <IDENTIFIER> <LPAREN> list? <RPAREN>
protected AstNode	or(boolean required)	or := and (<OR> and)*
protected AstParameters	params()	params := <LPAREN> (expr (<COMMA> expr)*)? <RPAREN>
protected Number	parseFloat(String string)	Parse a floating point literal.
protected Number	parseInteger(String string)	Parse an integer literal.
void	putExtensionHandler(Scanner.ExtensionToken token, Parser.ExtensionHandler extension)
protected AstNode	text()	text := <TEXT>
Tree	tree()	tree := text? ((dynamic text?)+ | (deferred text?)+)?
protected AstNode	unary(boolean required)	unary := <NOT> unary | <MINUS> unary | <EMPTY> unary | value
protected AstNode	value()	value := (nonliteral | literal) (<DOT> <IDENTIFIER> | <LBRACK> expr <RBRACK>)*

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

context

protected final Builder context

scanner

protected final Scanner scanner

extensions

protected Map<Scanner.ExtensionToken,Parser.ExtensionHandler> extensions

Constructor Detail

Parser

public Parser(Builder context,
              String input)

Method Detail

createScanner

protected Scanner createScanner(String expression)

putExtensionHandler

public void putExtensionHandler(Scanner.ExtensionToken token,
                                Parser.ExtensionHandler extension)

getExtensionHandler

protected Parser.ExtensionHandler getExtensionHandler(Scanner.Token token)

parseInteger

protected Number parseInteger(String string)
                       throws Parser.ParseException

Parse an integer literal.

Parameters:

string - string to parse

Returns:

Long.valueOf(string)

Throws:

Parser.ParseException

parseFloat

protected Number parseFloat(String string)
                     throws Parser.ParseException

Parse a floating point literal.

Parameters:

string - string to parse

Returns:

Double.valueOf(string)

Throws:

Parser.ParseException

createAstBinary

protected AstBinary createAstBinary(AstNode left,
                                    AstNode right,
                                    AstBinary.Operator operator)

createAstBracket

protected AstBracket createAstBracket(AstNode base,
                                      AstNode property,
                                      boolean lvalue,
                                      boolean strict)

createAstChoice

protected AstChoice createAstChoice(AstNode question,
                                    AstNode yes,
                                    AstNode no)

createAstComposite

protected AstComposite createAstComposite(List<AstNode> nodes)

createAstDot

protected AstDot createAstDot(AstNode base,
                              String property,
                              boolean lvalue)

createAstFunction

protected AstFunction createAstFunction(String name,
                                        int index,
                                        AstParameters params)

createAstIdentifier

protected AstIdentifier createAstIdentifier(String name,
                                            int index)

createAstMethod

protected AstMethod createAstMethod(AstProperty property,
                                    AstParameters params)

createAstUnary

protected AstUnary createAstUnary(AstNode child,
                                  AstUnary.Operator operator)

getFunctions

protected final List<FunctionNode> getFunctions()

getIdentifiers

protected final List<IdentifierNode> getIdentifiers()

getToken

protected final Scanner.Token getToken()

fail

protected void fail(String expected)
             throws Parser.ParseException

throw exception

Throws:

Parser.ParseException

fail

protected void fail(Scanner.Symbol expected)
             throws Parser.ParseException

throw exception

Throws:

Parser.ParseException

lookahead

protected final Scanner.Token lookahead(int index)
                                 throws Scanner.ScanException,
                                        Parser.ParseException

get lookahead symbol.

Throws:

Scanner.ScanException

Parser.ParseException

consumeToken

protected final Scanner.Token consumeToken()
                                    throws Scanner.ScanException,
                                           Parser.ParseException

consume current token (get next token).

Returns:

the consumed token (which was the current token when calling this method)

Throws:

Scanner.ScanException

Parser.ParseException

consumeToken

protected final Scanner.Token consumeToken(Scanner.Symbol expected)
                                    throws Scanner.ScanException,
                                           Parser.ParseException

consume current token (get next token); throw exception if the current token doesn't match the expected symbol.

Throws:

Scanner.ScanException

Parser.ParseException

tree

public Tree tree()
          throws Scanner.ScanException,
                 Parser.ParseException

tree := text? ((dynamic text?)+ | (deferred text?)+)?

Throws:

Scanner.ScanException

Parser.ParseException

text

protected AstNode text()
                throws Scanner.ScanException,
                       Parser.ParseException

text := <TEXT>

Throws:

Scanner.ScanException

Parser.ParseException

eval

protected AstEval eval()
                throws Scanner.ScanException,
                       Parser.ParseException

eval := dynamic | deferred

Throws:

Scanner.ScanException

Parser.ParseException

eval

protected AstEval eval(boolean required,
                       boolean deferred)
                throws Scanner.ScanException,
                       Parser.ParseException

dynmamic := <START_EVAL_DYNAMIC> expr <END_EVAL> deferred := <START_EVAL_DEFERRED> expr <END_EVAL>

Throws:

Scanner.ScanException

Parser.ParseException

expr

protected AstNode expr(boolean required)
                throws Scanner.ScanException,
                       Parser.ParseException

expr := or (<QUESTION> expr <COLON> expr)?

Throws:

Scanner.ScanException

Parser.ParseException

or

protected AstNode or(boolean required)
              throws Scanner.ScanException,
                     Parser.ParseException

or := and (<OR> and)*

Throws:

Scanner.ScanException

Parser.ParseException

and

protected AstNode and(boolean required)
               throws Scanner.ScanException,
                      Parser.ParseException

and := eq (<AND> eq)*

Throws:

Scanner.ScanException

Parser.ParseException

eq

protected AstNode eq(boolean required)
              throws Scanner.ScanException,
                     Parser.ParseException

eq := cmp (<EQ> cmp | <NE> cmp)*

Throws:

Scanner.ScanException

Parser.ParseException

cmp

protected AstNode cmp(boolean required)
               throws Scanner.ScanException,
                      Parser.ParseException

cmp := add (<LT> add | <LE> add | <GE> add | <GT> add)*

Throws:

Scanner.ScanException

Parser.ParseException

add

protected AstNode add(boolean required)
               throws Scanner.ScanException,
                      Parser.ParseException

add := add (<PLUS> mul | <MINUS> mul)*

Throws:

Scanner.ScanException

Parser.ParseException

mul

protected AstNode mul(boolean required)
               throws Scanner.ScanException,
                      Parser.ParseException

mul := unary (<MUL> unary | <DIV> unary | <MOD> unary)*

Throws:

Scanner.ScanException

Parser.ParseException

unary

protected AstNode unary(boolean required)
                 throws Scanner.ScanException,
                        Parser.ParseException

unary := <NOT> unary | <MINUS> unary | <EMPTY> unary | value

Throws:

Scanner.ScanException

Parser.ParseException

value

protected AstNode value()
                 throws Scanner.ScanException,
                        Parser.ParseException

value := (nonliteral | literal) (<DOT> <IDENTIFIER> | <LBRACK> expr <RBRACK>)*

Throws:

Scanner.ScanException

Parser.ParseException

nonliteral

protected AstNode nonliteral()
                      throws Scanner.ScanException,
                             Parser.ParseException

nonliteral := <IDENTIFIER> | function | <LPAREN> expr <RPAREN> function := (<IDENTIFIER> <COLON>)? <IDENTIFIER> <LPAREN> list? <RPAREN>

Throws:

Scanner.ScanException

Parser.ParseException

params

protected AstParameters params()
                        throws Scanner.ScanException,
                               Parser.ParseException

params := <LPAREN> (expr (<COMMA> expr)*)? <RPAREN>

Throws:

Scanner.ScanException

Parser.ParseException

literal

protected AstNode literal()
                   throws Scanner.ScanException,
                          Parser.ParseException

literal := <TRUE> | <FALSE> | <STRING> | <INTEGER> | <FLOAT> | <NULL>

Throws:

Scanner.ScanException

Parser.ParseException

function

protected final AstFunction function(String name,
                                     AstParameters params)

identifier

protected final AstIdentifier identifier(String name)