oracle.javatools.parser.util
Interface ExpressionObject

public interface ExpressionObject

This is the ExpressionObject interface used by the ExpressionStack. See the ExpressionStack for details. During processing, the expression tree is built via the methods addOperand(...) and closeOperator(...) which are called on operator expressions. Only classify() should be called on the atom expressions.

Field Summary

static int	ATOM This ExpressionObject is not an operator.
static int	INFIX_OP This ExpressionObject is an infix operator.
static int	LEFT_ASSOC This operator is left associativity.
static int	MAX_PRECEDENCE No ExpressionObject should return a precedence worse than this value.
static int	NON_ASSOC This operator is non-associative.
static int	POSTFIX_OP This ExpressionObject is a postfix operator.
static int	PREFIX_OP This ExpressionObject is a prefix operator.
static int	RIGHT_ASSOC This operator is right associative.
static int	TERNARY_OP This ExpressionObject is a ternary operator.

Method Summary

void	addOperand(ExpressionObject e) Adds an operand to this operator object.
int	classify() Returns the whether an ExpressionObject is an atom, a prefix operator, an infix operator, or a postfix operator.
void	closeOperator(java.lang.Object closingArgument) Called after all operands have been added to allow post-processing.
int	getAssociativity() Returns the associativity of this operator according to the above constants.
int	getPrecedence() Returns a positive number representing the precedence of this ExpressionObject operator.

Field Detail

ATOM

public static final int ATOM

This ExpressionObject is not an operator.

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Constant Field Values

PREFIX_OP

public static final int PREFIX_OP

This ExpressionObject is a prefix operator. It takes one operand.

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Constant Field Values

INFIX_OP

public static final int INFIX_OP

This ExpressionObject is an infix operator. It takes two operands. The operands will be added via addOperand() in order.

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Constant Field Values

POSTFIX_OP

public static final int POSTFIX_OP

This ExpressionObject is a postfix operator. It takes one operand.

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Constant Field Values

TERNARY_OP

public static final int TERNARY_OP

This ExpressionObject is a ternary operator. It takes three operands. The infix stream order should be "operand op operand operand".

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Constant Field Values

MAX_PRECEDENCE

public static final int MAX_PRECEDENCE

No ExpressionObject should return a precedence worse than this value.

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Constant Field Values

LEFT_ASSOC

public static final int LEFT_ASSOC

This operator is left associativity.

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Constant Field Values

NON_ASSOC

public static final int NON_ASSOC

This operator is non-associative.

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Constant Field Values

RIGHT_ASSOC

public static final int RIGHT_ASSOC

This operator is right associative.

See Also:

Constant Field Values

Method Detail

classify

public int classify()

Returns the whether an ExpressionObject is an atom, a prefix operator, an infix operator, or a postfix operator.

getPrecedence

public int getPrecedence()

Returns a positive number representing the precedence of this ExpressionObject operator. The smaller the value, the more tightly binding this operator is. No precedence should exceed MAX_PRECEDENCE. Prefix and postfix operators should not have the same precedence. If so, you may get an incorrect tree.

getAssociativity

public int getAssociativity()

Returns the associativity of this operator according to the above constants. Any two operators that have the same precedence must also share the same associativity. If not, you may get an incorrect tree.

addOperand

public void addOperand(ExpressionObject e)

Adds an operand to this operator object.

closeOperator

public void closeOperator(java.lang.Object closingArgument)

Called after all operands have been added to allow post-processing.

Parameters:

closingArgument - The closing argument passed to the ExpressionStack.