parsii.eval

Class BinaryOperation

java.lang.Object

parsii.eval.BinaryOperation

All Implemented Interfaces:

Expression

public class BinaryOperation
extends Object
implements Expression

Represents a binary operation.

A binary operation has two sub-expressions. A set of supported operations is also defined. If both arguments are constant, simplifying this expression will again lead to a constant expression.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BinaryOperation.Op Enumerates the operations supported by this expression.

Field Summary

Fields

Modifier and Type	Field and Description
static double	EPSILON When comparing two double values, those are considered equal, if their difference is lower than the defined epsilon.

Constructor Summary

Constructors

Constructor and Description
BinaryOperation(BinaryOperation.Op op, Expression left, Expression right) Creates a new binary operator for the given operator and operands.

Method Summary

Modifier and Type	Method and Description
double	evaluate() Evaluates the expression to a double number.
Expression	getLeft() Returns the left operand
BinaryOperation.Op	getOp() Returns the operation performed by this binary operation.
Expression	getRight() Returns the right operand
boolean	isSealed() Determines if the operation is sealed and operands must not be re-ordered.
void	seal() Marks an operation as sealed, meaning that re-ordering or operations on the same level must not be re-ordered.
void	setLeft(Expression left) Replaces the left operand of the operation with the given expression.
Expression	simplify() Returns a simplified version of this expression.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface parsii.eval.Expression

isConstant

Field Detail

EPSILON

public static final double EPSILON

When comparing two double values, those are considered equal, if their difference is lower than the defined epsilon. This is way better than relying on an exact comparison due to rounding errors

See Also:

Constant Field Values

Constructor Detail

BinaryOperation

public BinaryOperation(BinaryOperation.Op op,
                       Expression left,
                       Expression right)

Creates a new binary operator for the given operator and operands.

Parameters:

op - the operator of the operation

left - the left operand

right - the right operand

Method Detail

getOp

public BinaryOperation.Op getOp()

Returns the operation performed by this binary operation.

Returns:

the operation performed

getLeft

public Expression getLeft()

Returns the left operand

Returns:

the left operand of this operation

setLeft

public void setLeft(Expression left)

Replaces the left operand of the operation with the given expression.

Parameters:

left - the new expression to be used as left operand

getRight

public Expression getRight()

Returns the right operand

Returns:

the right operand of this operation

seal

public void seal()

Marks an operation as sealed, meaning that re-ordering or operations on the same level must not be re-ordered.

Binary operations are sealed if they're e.g. surrounded by braces.

isSealed

public boolean isSealed()

Determines if the operation is sealed and operands must not be re-ordered.

Returns:

true if the operation is protected by braces and operands might not be exchanged with operations nearby.

evaluate

public double evaluate()

Description copied from interface: Expression

Evaluates the expression to a double number.

Specified by:

evaluate in interface Expression

Returns:

the double value as a result of evaluating this expression. Returns NaN if an error occurs

simplify

public Expression simplify()

Description copied from interface: Expression

Returns a simplified version of this expression.

Specified by:

simplify in interface Expression

Returns:

a simplified version of this expression or this if the expression cannot be simplified

toString

public String toString()

Overrides:

toString in class Object