uk.ac.sheffield.vtts.model

Class Arithmetic

java.lang.Object

uk.ac.sheffield.vtts.model.Element

uk.ac.sheffield.vtts.model.Named

uk.ac.sheffield.vtts.model.Expression

uk.ac.sheffield.vtts.model.Function

uk.ac.sheffield.vtts.model.Arithmetic

public class Arithmetic
extends Function

Arithmetic represents a numerical function with an arithmetic operator root node. The operands are expected to be numbers. There are six arithmetic operators, whose names include: plus, minus, times, divide, modulo and negate. There are six legal numeric types, including: Byte, Short, Integer, Long, Float and Double.

Version:

Broker@Cloud 1.0

Author:

Anthony J H Simons

Field Summary

Fields inherited from class uk.ac.sheffield.vtts.model.Function

expressions, maxOperands

Fields inherited from class uk.ac.sheffield.vtts.model.Expression

factory, type

Fields inherited from class uk.ac.sheffield.vtts.model.Named

name

Constructor Summary

Constructors

Constructor and Description
Arithmetic() Creates a default Arithmetic expression.
Arithmetic(java.lang.String name) Creates a named Arithmetic expression.
Arithmetic(java.lang.String name, java.lang.String type) Creates a named and typed Arithmetic expression.

Method Summary

Methods

Modifier and Type	Method and Description
protected java.lang.Number	divide(java.lang.Object first, java.lang.Object second) Computes the quotient of two numerical values.
java.lang.Number	evaluate() Executes this Arithmetic on its operands.
protected java.lang.Number	minus(java.lang.Object first, java.lang.Object second) Computes the difference of two numerical values.
protected java.lang.Number	modulo(java.lang.Object first, java.lang.Object second) Computes the modulo of two numerical values.
protected void	nameCheck() Checks the name of an Arithmetic expression and sets the expected number of operands.
protected java.lang.Number	negate(java.lang.Object value) Computes the negation of a numerical value.
protected java.lang.Number	plus(java.lang.Object first, java.lang.Object second) Computes the sum of two numerical values.
void	rebind(java.lang.Object result) Rebinds the unbound operands of this Arithmetic expression, so that it yields the given expected result.
protected java.lang.Number	times(java.lang.Object first, java.lang.Object second) Computes the product of two numerical values.
protected void	typeCheck() Checks the types of the operands of this Arithmetic expression.

Methods inherited from class uk.ac.sheffield.vtts.model.Function

addExpression, assign, equals, getExpressions, getType, hashCode, isAssignable, isBound, operand, rebind, resolve, setName, toString, unbind

Methods inherited from class uk.ac.sheffield.vtts.model.Expression

getName, isBottom, isOrdered, setType

Methods inherited from class uk.ac.sheffield.vtts.model.Named

setName

Methods inherited from class uk.ac.sheffield.vtts.model.Element

safeEquals, safeHashCode, semanticError

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

Arithmetic

public Arithmetic()

Creates a default Arithmetic expression.

Arithmetic

public Arithmetic(java.lang.String name)

Creates a named Arithmetic expression.

Parameters:

name - the arithmetic operator name.

Arithmetic

public Arithmetic(java.lang.String name,
          java.lang.String type)

Creates a named and typed Arithmetic expression.

Parameters:

name - the name of the arithmetic operator.

type - the result type of the expression.

Method Detail

nameCheck

protected void nameCheck()

Checks the name of an Arithmetic expression and sets the expected number of operands. All arithmetic operators expect two operands, apart from "negate", which expects one operand.

Specified by:

nameCheck in class Function

typeCheck

protected void typeCheck()

Checks the types of the operands of this Arithmetic expression. The operands must have one of the six legal numerical types; and if there are two operands, these must be of the same type. The result must be of the same type as the operands. Caches the result type, which is used as a dispatching token during evaluation.

Specified by:

typeCheck in class Function

evaluate

public java.lang.Number evaluate()

Executes this Arithmetic on its operands. Expects one operand for a negation, and two operands otherwise. Checks the consistency of the types of the operands and result, then branches according to the name of the arithmetical operator.

Specified by:

evaluate in class Expression

Returns:

the arithmetical result, as a Number.

rebind

public void rebind(java.lang.Object result)

Rebinds the unbound operands of this Arithmetic expression, so that it yields the given expected result.

Specified by:

rebind in class Expression

Parameters:

result - the expected result of this Arithmetic expression.

negate

protected java.lang.Number negate(java.lang.Object value)

Computes the negation of a numerical value.

Parameters:

value - a numerical value.

Returns:

the negation of this value.

plus

protected java.lang.Number plus(java.lang.Object first,
                    java.lang.Object second)

Computes the sum of two numerical values.

Parameters:

first - the first numerical value.

second - the second numerical value.

Returns:

the sum of the two values.

minus

protected java.lang.Number minus(java.lang.Object first,
                     java.lang.Object second)

Computes the difference of two numerical values.

Parameters:

first - the first numerical value.

second - the second numerical value.

Returns:

the difference of the first minus the second value.

times

protected java.lang.Number times(java.lang.Object first,
                     java.lang.Object second)

Computes the product of two numerical values.

Parameters:

first - the first numerical value.

second - the second numerical value.

Returns:

the product of the two values.

divide

protected java.lang.Number divide(java.lang.Object first,
                      java.lang.Object second)

Computes the quotient of two numerical values.

Parameters:

first - the first numerical value.

second - the second numerical value.

Returns:

the quotient of the first divided by the second value.

modulo

protected java.lang.Number modulo(java.lang.Object first,
                      java.lang.Object second)

Computes the modulo of two numerical values.

Parameters:

first - the first numerical value.

second - the second numerical value.

Returns:

the remainder of the first modulo the second value.