dragon.ir.query
Class SimpleExpression

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

All Implemented Interfaces:

Expression

public class SimpleExpression

extends AbstractExpression

Simple 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

SimpleExpression(java.lang.String[] expression)

SimpleExpression(java.lang.String field, Operator optr, java.lang.Object testValue)

Method Summary

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

SimpleExpression

public SimpleExpression(java.lang.String field,
                        Operator optr,
                        java.lang.Object testValue)

SimpleExpression

public SimpleExpression(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

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

getField

public java.lang.String getField()

getTestValue

public java.lang.Object getTestValue()

getOperator

public Operator getOperator()

Specified by:

getOperator in interface Expression

Overrides:

getOperator in class AbstractExpression