jmathlib.core.tokens
Class Expression

java.lang.Object
  jmathlib.core.interpreter.RootObject
      jmathlib.core.tokens.Token
          jmathlib.core.tokens.OperandToken
              jmathlib.core.tokens.Expression

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, ErrorCodes, TokenConstants

public class Expression
extends OperandToken

Class implementing a tree where each node has a variable no of children

See Also:

Serialized Form

Field Summary

Fields inherited from class jmathlib.core.tokens.Token

priority

Fields inherited from interface jmathlib.core.constants.TokenConstants

ADDSUB_PRIORITY, AND_PRIORITY, ANDAND_PRIORITY, ASSIGN_PRIORITY, BRACKET_PRIORITY, COMPARE_PRIORITY, CONCAT, MATRIX, MULDIV_PRIORITY, OR_PRIORITY, OROR_PRIORITY, PARAMETER, POWER_PRIORITY, RELATION_PRIORITY, SINGLE, ttDelimiter, ttNotSet, ttOperand, ttOperator

Fields inherited from interface jmathlib.core.constants.ErrorCodes

ERR_BRACKET_OPEN, ERR_BRACKET_ORDER, ERR_FUNCTION_NOT_FOUND, ERR_FUNCTION_NOT_IMPLEMENTED, ERR_INSUFFICIENT_PARAMETERS, ERR_INVALID_PARAMETER, ERR_LVALUE_REQUIRED, ERR_MATRIX_SINGULAR, ERR_NOT_SQUARE_MATRIX, ERR_OPNOTSUPPORTED, ERR_TOO_MANY_PARAMETERS, ERR_USER_ERROR, ERR_VARIABLE_NOTDEFINED, OK, OK_FUNCTION_PROCESS

Constructor Summary

Expression()
Default constructor - creates an expression with a null operator and no operands

Expression(OperatorToken _data)
Creates an expression with no operands

Expression(OperatorToken _data, OperandToken operand)
Creates an expression with one operand

Expression(OperatorToken _data, OperandToken[] _children, int _noChildren)
Creates an expression with an array of operands

Expression(OperatorToken _data, OperandToken left, OperandToken right)
Creates an expression with two operands

Expression(OperatorToken _data, OperandToken op1, OperandToken op2, OperandToken op3)
Creates an expression with three operands

Method Summary

OperandToken	evaluate(Token[] ops, GlobalValues globals) evaluate the data item held within this node
OperandToken	getChild(int childNo) Get the a child with a specific index
int	getChildNo()
java.util.Enumeration	getChildren() function to access all children of a node within the expression tree
OperandToken	getCurrentChild()
OperatorToken	getData() retrieves the data object
OperandToken	getLeft() Get the first child of this node
int	getNumberOfChildren()
OperandToken	getRight() Get the last child of this node
void	insert(Token _data) insert a child node on this Expression if _data is a Expression then it just gets added to the current node Otherwise a new node is created and this is added to the current node
boolean	isLeaf() checks if this is a leaf node of the expression tree
boolean	isNumeric() Checks if this operand is a numeric value
void	setChild(int childNo, OperandToken child) set the child with a specific index
void	setData(OperatorToken _data) Sets the operator of the expression
java.lang.String	toString() Converts the expression to a string

Methods inherited from class jmathlib.core.tokens.OperandToken

add, asArray, Children, ctranspose, derivative, divide, expand, factorial, integral, isNull, leftDivide, mpower, mPower, multiply, negate, power, scalarDivide, scalarLeftDivide, scalarMultiply, simplify, subst, subtract, transpose

Methods inherited from class jmathlib.core.tokens.Token

isDisplayResult, setDisplayResult, toMathMlString, toString

Methods inherited from class jmathlib.core.interpreter.RootObject

clone, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

Expression

public Expression()

Default constructor - creates an expression with a null operator and no operands

Expression

public Expression(OperatorToken _data)

Creates an expression with no operands

Parameters:

_data - = the expressions operator

Expression

public Expression(OperatorToken _data,
                  OperandToken operand)

Creates an expression with one operand

Parameters:

_data - = the expressions operator

operand - = the expressions operand

Expression

public Expression(OperatorToken _data,
                  OperandToken left,
                  OperandToken right)

Creates an expression with two operands

Parameters:

_data - = the expressions operator

left - = the left hand operand

right - = the right hand operand

Expression

public Expression(OperatorToken _data,
                  OperandToken op1,
                  OperandToken op2,
                  OperandToken op3)

Creates an expression with three operands

Parameters:

_data - = the expressions operator

first - = the left hand operand

second - = the middle operand

third - = the right hand operand

Expression

public Expression(OperatorToken _data,
                  OperandToken[] _children,
                  int _noChildren)

Creates an expression with an array of operands

Parameters:

data - = the expressions operator

operands - = and array of operands

_noChildren - = the number of operands

Method Detail

getData

public OperatorToken getData()

retrieves the data object

Returns:

the operator assigned to the expression

getNumberOfChildren

public int getNumberOfChildren()

Returns:

the number of children

setData

public void setData(OperatorToken _data)

Sets the operator of the expression

Parameters:

_data - = the expressions operator

getChild

public OperandToken getChild(int childNo)

Get the a child with a specific index

Parameters:

childNo - = the index of the operand

Returns:

the specified operand

setChild

public void setChild(int childNo,
                     OperandToken child)

set the child with a specific index

Parameters:

childNo - = the index of the child

child - = the value to set it to

getLeft

public OperandToken getLeft()

Get the first child of this node

Returns:

the first operand

getRight

public OperandToken getRight()

Get the last child of this node

Returns:

the last operand

insert

public void insert(Token _data)

insert a child node on this Expression if _data is a Expression then it just gets added to the current node Otherwise a new node is created and this is added to the current node

Parameters:

_data - = the operand to add

evaluate

public OperandToken evaluate(Token[] ops,
                             GlobalValues globals)

evaluate the data item held within this node

Specified by:

evaluate in class Token

Parameters:

ops - = the expressions operands

Returns:

the result of the expression as an OperandToken

toString

public java.lang.String toString()

Converts the expression to a string

Specified by:

toString in class Token

Returns:

string representation of expression

isNumeric

public boolean isNumeric()

Checks if this operand is a numeric value

Overrides:

isNumeric in class OperandToken

Returns:

true if this is a number, false if it's an algebraic expression

getChildNo

public int getChildNo()

Returns:

the index number of the current child expression

getCurrentChild

public OperandToken getCurrentChild()

Returns:

the expression being executed

isLeaf

public boolean isLeaf()

checks if this is a leaf node of the expression tree

Overrides:

isLeaf in class OperandToken

Returns:

false if this expression has any children

getChildren

public java.util.Enumeration getChildren()

function to access all children of a node within the expression tree

Returns:

all the nodes children as a enumeration