info.aduna.gee.publication.servlets.car
Class Symbol

java.lang.Object
  info.aduna.gee.publication.servlets.car.Symbol

public class Symbol
extends Object

An input symbol in an expression.

Field Summary

ExpressionNode	enode The reduced expression node, if symbol type if SYM_EXPRNODE.
long	nval The value of a TK_NUMBER token.
int	stype Symbol type of the symbol.
static int	SYM_EXPRNODE
static int	SYM_TERMINAL
static int	SYM_UNKNOWN
static int	TK_AND
static int	TK_BRACKETL
static int	TK_BRACKETR
static int	TK_EOE
static int	TK_NOT
static int	TK_NUMBER
static int	TK_OR
int	ttype The terminal type of the symbol, if symbol type if SYM_TERMINAL.

Constructor Summary

Symbol()
Create an empty symbol.

Symbol(int type, ExpressionNode en)
Create an Expression token with symbol type specified as SYM_EXPRNODE, and an expression node.

Symbol(int type, int tk)
Create a token symbol with symbol type and token type.

Symbol(int type, int tk, long val)
Create a Number token with symbol type specified as SYM_TERMINAL, token type specified as TK_NUMBER and a value

Method Summary

boolean	equal(Symbol a)
boolean	greater(Symbol a)
boolean	isEOE()
boolean	isExpressionNode()
boolean	less(Symbol a)
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

SYM_UNKNOWN

public static final int SYM_UNKNOWN

See Also:

Constant Field Values

SYM_EXPRNODE

public static final int SYM_EXPRNODE

See Also:

Constant Field Values

SYM_TERMINAL

public static final int SYM_TERMINAL

See Also:

Constant Field Values

TK_EOE

public static final int TK_EOE

See Also:

Constant Field Values

TK_NUMBER

public static final int TK_NUMBER

See Also:

Constant Field Values

TK_BRACKETL

public static final int TK_BRACKETL

See Also:

Constant Field Values

TK_BRACKETR

public static final int TK_BRACKETR

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Constant Field Values

TK_NOT

public static final int TK_NOT

See Also:

Constant Field Values

TK_AND

public static final int TK_AND

See Also:

Constant Field Values

TK_OR

public static final int TK_OR

See Also:

Constant Field Values

stype

public int stype

Symbol type of the symbol.

ttype

public int ttype

The terminal type of the symbol, if symbol type if SYM_TERMINAL.

enode

public ExpressionNode enode

The reduced expression node, if symbol type if SYM_EXPRNODE.

nval

public long nval

The value of a TK_NUMBER token.

Constructor Detail

Symbol

public Symbol()

Create an empty symbol.

Symbol

public Symbol(int type,
              int tk)

Create a token symbol with symbol type and token type. It is used for creating symbols for operators, EOE and brackets.

Symbol

public Symbol(int type,
              int tk,
              long val)

Create a Number token with symbol type specified as SYM_TERMINAL, token type specified as TK_NUMBER and a value

Symbol

public Symbol(int type,
              ExpressionNode en)

Create an Expression token with symbol type specified as SYM_EXPRNODE, and an expression node.

Method Detail

isEOE

public boolean isEOE()

Returns:

true if the symbol represents the end of an expression.

isExpressionNode

public boolean isExpressionNode()

Returns:

true if the symbol represents an expression node.

equal

public boolean equal(Symbol a)
              throws ExpressionException

Returns:

true if current symbol has equal precedence to symbol a.

Throws:

ExpressionException

less

public boolean less(Symbol a)
             throws ExpressionException

Returns:

true if current symbol has lower precedence than symbol a.

Throws:

ExpressionException

greater

public boolean greater(Symbol a)
                throws ExpressionException

Returns:

true if current symbol has higher precedence than symbol a.

Throws:

ExpressionException

toString

public String toString()

Overrides:

toString in class Object

Returns:

the string representation of the current symbol.