dragon.ir.query
Class BoolExpression

java.lang.Object
  |
  +--dragon.ir.query.AbstractExpression
        |
        +--dragon.ir.query.BoolExpression

All Implemented Interfaces:

Expression

public class BoolExpression

extends AbstractExpression

Bool query expression

Copyright: Copyright (c) 2005

Company: IST, Drexel University

Version:

1.0

Author:

Davis Zhou

Field Summary

Fields inherited from class dragon.ir.query.AbstractExpression

expressionType, optr

Fields inherited from interface dragon.ir.query.Expression

EXPRESSION_BOOL, EXPRESSION_SIMPLE

Constructor Summary

BoolExpression(java.lang.String[] expression)

Method Summary

Expression	getChild(int index) This method returns null for simple expressions.
int	getChildNum() This method returns zero for simple expressions.
Operator	getOperator()
java.lang.String	toSQLExpression()
java.lang.String	toString()

Methods inherited from class dragon.ir.query.AbstractExpression

isBoolExpression, isSimpleExpression

Methods inherited from class java.lang.Object

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

Constructor Detail

BoolExpression

public BoolExpression(java.lang.String[] expression)

Method Detail

getChildNum

public int getChildNum()

Description copied from interface: Expression

This method returns zero for simple expressions. It returns the number of conditions for bool expression.

Returns:

the number of sub-expressions

getChild

public Expression getChild(int index)

Description copied from interface: Expression

This method returns null for simple expressions. It returns index-th conditions for bool expression.

Parameters:

index - the index of the child expression

Returns:

the specified child expression

getOperator

public Operator getOperator()

Specified by:

getOperator in interface Expression

Overrides:

getOperator in class AbstractExpression

toSQLExpression

public java.lang.String toSQLExpression()

Returns:

a string for SQL-formatted expression

toString

public java.lang.String toString()

Specified by:

toString in interface Expression

Overrides:

toString in class java.lang.Object

Returns:

a string for the expression