org.lsmp.djep.xjep
Class TreeUtils

java.lang.Object
  org.lsmp.djep.xjep.TreeUtils

public class TreeUtils
extends java.lang.Object

A set of Utility functions for working with JEP expression trees. Main methods are

• isConstant test if its a constant. Many other is... methods.
• getValue extracts the value from a node without needing to cast and check types.

Author:

rich

Field Summary

protected static Complex	CI Complex i
protected static Complex	CMINUSI Complex Minus i
protected static Complex	CMINUSONE Complex Minus One
protected static Complex	CONE Complex One
protected static Complex	CZERO Complex Zero
protected static java.lang.Double	MINUSONE Real Minus One
protected static java.lang.Double	NAN Real NaN
protected static java.lang.Double	NegInf Real NaN
protected static java.lang.Double	ONE Real One
protected static java.lang.Double	PosInf Real positive infinity
protected static java.lang.Double	ZERO Real zero.

Constructor Summary

TreeUtils()
Default constructor.

Method Summary

Complex	complexValue(Node node) Returns the Complex value represented by node
static Node	copyChildrenIfNeeded(Node node, Node[] children) Sets the children of a node if they have changed for it current children.
double	doubleValue(Node node) Returns the double value represented by node
static Node[]	getChildrenAsArray(Node node) returns the children of a node as an array of nodes.
java.lang.Object	getCI()
java.lang.Object	getCMINUSI()
java.lang.Object	getCMINUSONE()
java.lang.Object	getCONE()
java.lang.Object	getCZERO()
java.lang.Object	getMINUSONE()
java.lang.String	getName(Node node) Returns the value represented by node
java.lang.Object	getNAN()
java.lang.Object	getNegativeInfinity()
java.lang.Object	getNumber(double val)
java.lang.Object	getONE()
Operator	getOperator(Node node) returns the operator for a node or null if it is not an operator node.
java.lang.Object	getPositiveInfinity()
java.lang.Object	getValue(Node node) Returns the value represented by node
java.lang.Object	getZERO()
int	intValue(Node node) Returns the int value represented by node
boolean	isBinaryOperator(Node node)
boolean	isComplex(Node node) returns true if node is an ASTConstant of type Complex
boolean	isConstant(Node node) returns true if node is a ASTConstant
boolean	isFunction(Node node) returns true if node is an ASTFunNode
boolean	isInfinity(Node node) returns true if node is a ASTConstant with a Infinite component TODO do proper treatment of signed infinity
boolean	isInteger(Node node) returns true if node is a ASTConstant with Double value representing an integer.
boolean	isMinusOne(Node node) returns true if node is a ASTConstant with value Double(-1) or Complex(-1,0)
boolean	isNaN(Node node) returns true if node is a ASTConstant with a NaN component
boolean	isNegative(Node node) returns true if node is an ASTConstant with a negative Double value
boolean	isOne(Node node) returns true if node is a ASTConstant with value Double(1) or Complex(1,0)
boolean	isOperator(Node node) returns true if node is an ASTOpNode
boolean	isPositive(Node node) returns true if node is an ASTConstant with a positive Double value
boolean	isReal(Node node) returns true if node is a ASTConstant with Double value
boolean	isUnaryOperator(Node node)
boolean	isVariable(Node node) returns true if node is an ASTVarNode
boolean	isZero(Node node) returns true if node is a ASTConstant with value Double(0) or Complex(0,0)
boolean	isZero(Node node, double tol) returns true if node is a ASTConstant with value Double(0) or Complex(0,0)
long	longValue(Node node) Returns the long value represented by node

Methods inherited from class java.lang.Object

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

Field Detail

ZERO

protected static java.lang.Double ZERO

Real zero. Note that this is a Double, if a different number format is needed then this class should be sub-classed.

ONE

protected static java.lang.Double ONE

Real One

MINUSONE

protected static java.lang.Double MINUSONE

Real Minus One

CZERO

protected static Complex CZERO

Complex Zero

CONE

protected static Complex CONE

Complex One

CI

protected static Complex CI

Complex i

CMINUSONE

protected static Complex CMINUSONE

Complex Minus One

CMINUSI

protected static Complex CMINUSI

Complex Minus i

NAN

protected static java.lang.Double NAN

Real NaN

PosInf

protected static java.lang.Double PosInf

Real positive infinity

NegInf

protected static java.lang.Double NegInf

Real NaN

Constructor Detail

TreeUtils

public TreeUtils()

Default constructor. TODO Should use the NumberFactory to create numbers!

Method Detail

getName

public java.lang.String getName(Node node)
                         throws java.lang.IllegalArgumentException

Returns the value represented by node

Throws:

java.lang.IllegalArgumentException - if given something which is not an ASTConstant

getValue

public java.lang.Object getValue(Node node)
                          throws java.lang.IllegalArgumentException

Returns the value represented by node

Throws:

java.lang.IllegalArgumentException - if given something which is not an ASTConstant

doubleValue

public double doubleValue(Node node)
                   throws java.lang.IllegalArgumentException

Returns the double value represented by node

Throws:

java.lang.IllegalArgumentException - if given something which is not an ASTConstant with a Double value

longValue

public long longValue(Node node)
               throws java.lang.IllegalArgumentException

Returns the long value represented by node

Throws:

java.lang.IllegalArgumentException - if given something which is not an ASTConstant with a Double value

intValue

public int intValue(Node node)
             throws java.lang.IllegalArgumentException

Returns the int value represented by node

Throws:

java.lang.IllegalArgumentException - if given something which is not an ASTConstant with a Double value

complexValue

public Complex complexValue(Node node)
                     throws java.lang.IllegalArgumentException

Returns the Complex value represented by node

Throws:

java.lang.IllegalArgumentException - if given something which is not an ASTConstant with a Complex value

isConstant

public boolean isConstant(Node node)

returns true if node is a ASTConstant

isReal

public boolean isReal(Node node)

returns true if node is a ASTConstant with Double value

isInteger

public boolean isInteger(Node node)

returns true if node is a ASTConstant with Double value representing an integer.

isZero

public boolean isZero(Node node)

returns true if node is a ASTConstant with value Double(0) or Complex(0,0)

isZero

public boolean isZero(Node node,
                      double tol)

returns true if node is a ASTConstant with value Double(0) or Complex(0,0)

Parameters:

tol - tolerance for testing for zero

isOne

public boolean isOne(Node node)

returns true if node is a ASTConstant with value Double(1) or Complex(1,0)

isMinusOne

public boolean isMinusOne(Node node)

returns true if node is a ASTConstant with value Double(-1) or Complex(-1,0)

isInfinity

public boolean isInfinity(Node node)

returns true if node is a ASTConstant with a Infinite component TODO do proper treatment of signed infinity

isNaN

public boolean isNaN(Node node)

returns true if node is a ASTConstant with a NaN component

isNegative

public boolean isNegative(Node node)

returns true if node is an ASTConstant with a negative Double value

isPositive

public boolean isPositive(Node node)

returns true if node is an ASTConstant with a positive Double value

isComplex

public boolean isComplex(Node node)

returns true if node is an ASTConstant of type Complex

isVariable

public boolean isVariable(Node node)

returns true if node is an ASTVarNode

isOperator

public boolean isOperator(Node node)

returns true if node is an ASTOpNode

isBinaryOperator

public boolean isBinaryOperator(Node node)

isUnaryOperator

public boolean isUnaryOperator(Node node)

getOperator

public Operator getOperator(Node node)

returns the operator for a node or null if it is not an operator node.

isFunction

public boolean isFunction(Node node)

returns true if node is an ASTFunNode

copyChildrenIfNeeded

public static Node copyChildrenIfNeeded(Node node,
                                        Node[] children)
                                 throws ParseException

Sets the children of a node if they have changed for it current children.

Throws:

ParseException

getChildrenAsArray

public static Node[] getChildrenAsArray(Node node)

returns the children of a node as an array of nodes.

getCI

public java.lang.Object getCI()

getCMINUSI

public java.lang.Object getCMINUSI()

getCMINUSONE

public java.lang.Object getCMINUSONE()

getCONE

public java.lang.Object getCONE()

getCZERO

public java.lang.Object getCZERO()

getMINUSONE

public java.lang.Object getMINUSONE()

getONE

public java.lang.Object getONE()

getZERO

public java.lang.Object getZERO()

getNAN

public java.lang.Object getNAN()

getPositiveInfinity

public java.lang.Object getPositiveInfinity()

getNegativeInfinity

public java.lang.Object getNegativeInfinity()

getNumber

public java.lang.Object getNumber(double val)