org.jpox.query.expression
Class Expression

java.lang.Object
  org.jpox.query.expression.Expression

Direct Known Subclasses:

BooleanExpression, CreatorExpression, DyadicExpression, InvokeExpression, Literal, OrderExpression, PrimaryExpression, VariableExpression

public abstract class Expression
extends java.lang.Object

A Scalar expression in a Query. Used to compute values with a resulting type

Version:

$Revision: 1.34 $

Nested Class Summary

protected static class	Expression.DyadicOperator "Dyadic" operator performs operation on one or two operands
protected static class	Expression.MonadicOperator "Monadic" operator performs a function on one operand.
protected static class	Expression.Operator Inner class representing an Operator

Field Summary

protected Expression	left
protected static Localiser	LOCALISER Localiser for messages
protected Expression.Operator	lowestOperator
protected Expression.Operator	op
static Expression.DyadicOperator	OP_ADD ADD
static Expression.DyadicOperator	OP_AND AND
static Expression.DyadicOperator	OP_BETWEEN BETWEEN
static Expression.MonadicOperator	OP_COM COM
static Expression.DyadicOperator	OP_CONCAT CONCAT
static Expression.DyadicOperator	OP_DIV DIV
static Expression.DyadicOperator	OP_EQ EQ
static Expression.DyadicOperator	OP_GT GT
static Expression.DyadicOperator	OP_GTEQ GTEQ
static Expression.DyadicOperator	OP_IN IN
static Expression.DyadicOperator	OP_IS IS
static Expression.DyadicOperator	OP_ISNOT ISNOT
static Expression.DyadicOperator	OP_LIKE LIKE
static Expression.DyadicOperator	OP_LT LT
static Expression.DyadicOperator	OP_LTEQ LTEQ
static Expression.DyadicOperator	OP_MOD MOD
static Expression.DyadicOperator	OP_MUL MUL
static Expression.MonadicOperator	OP_NEG NEG
static Expression.MonadicOperator	OP_NOT NOT
static Expression.DyadicOperator	OP_NOTEQ NOTEQ
static Expression.DyadicOperator	OP_OR OR
static Expression.DyadicOperator	OP_SUB SUB
protected Expression	right
protected Symbol	symbol

Constructor Summary

protected	Expression() Constructor.
protected	Expression(Expression.MonadicOperator op, Expression operand) Perform a function op on operand
protected	Expression(Expression operand1, Expression.DyadicOperator op, Expression operand2) Performs a function on two arguments.

Method Summary

abstract Symbol	bind()
abstract java.lang.Object	evaluate(ExpressionEvaluator eval)
Expression	getLeft()
Expression.Operator	getOperator()
Expression	getRight()
Symbol	getSymbol()

Methods inherited from class java.lang.Object

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

Field Detail

LOCALISER

protected static final Localiser LOCALISER

Localiser for messages

op

protected Expression.Operator op

left

protected Expression left

right

protected Expression right

symbol

protected Symbol symbol

OP_OR

public static final Expression.DyadicOperator OP_OR

OR

OP_AND

public static final Expression.DyadicOperator OP_AND

AND

OP_NOT

public static final Expression.MonadicOperator OP_NOT

NOT

OP_EQ

public static final Expression.DyadicOperator OP_EQ

EQ

OP_NOTEQ

public static final Expression.DyadicOperator OP_NOTEQ

NOTEQ

OP_LT

public static final Expression.DyadicOperator OP_LT

LT

OP_LTEQ

public static final Expression.DyadicOperator OP_LTEQ

LTEQ

OP_GT

public static final Expression.DyadicOperator OP_GT

GT

OP_GTEQ

public static final Expression.DyadicOperator OP_GTEQ

GTEQ

OP_LIKE

public static final Expression.DyadicOperator OP_LIKE

LIKE

OP_BETWEEN

public static final Expression.DyadicOperator OP_BETWEEN

BETWEEN

OP_IS

public static final Expression.DyadicOperator OP_IS

IS

OP_ISNOT

public static final Expression.DyadicOperator OP_ISNOT

ISNOT

OP_IN

public static final Expression.DyadicOperator OP_IN

IN

OP_ADD

public static final Expression.DyadicOperator OP_ADD

ADD

OP_SUB

public static final Expression.DyadicOperator OP_SUB

SUB

OP_CONCAT

public static final Expression.DyadicOperator OP_CONCAT

CONCAT

OP_MUL

public static final Expression.DyadicOperator OP_MUL

MUL

OP_DIV

public static final Expression.DyadicOperator OP_DIV

DIV

OP_MOD

public static final Expression.DyadicOperator OP_MOD

MOD

OP_NEG

public static final Expression.MonadicOperator OP_NEG

NEG

OP_COM

public static final Expression.MonadicOperator OP_COM

COM

lowestOperator

protected Expression.Operator lowestOperator

Constructor Detail

Expression

protected Expression()

Constructor.

Parameters:

qs - The Query Expression

Expression

protected Expression(Expression.MonadicOperator op,
                     Expression operand)

Perform a function op on operand

Parameters:

op - operator

operand - operand

Expression

protected Expression(Expression operand1,
                     Expression.DyadicOperator op,
                     Expression operand2)

Performs a function on two arguments. op(operand1,operand2) operand1 op operand2

Parameters:

operand1 - the first expression

op - the operator between operands

operand2 - the second expression

Method Detail

evaluate

public abstract java.lang.Object evaluate(ExpressionEvaluator eval)

getOperator

public Expression.Operator getOperator()

getLeft

public Expression getLeft()

getRight

public Expression getRight()

getSymbol

public Symbol getSymbol()

bind

public abstract Symbol bind()