org.lsmp.djep.xjep
Class XJep

java.lang.Object
  org.nfunk.jep.JEP
      org.lsmp.djep.xjep.XJep

Direct Known Subclasses:

DJep

public class XJep

extends JEP

An extended version of JEP adds various routines for working with trees. Has a NodeFactory, and OperatorSet, TreeUtils and Visitors DoNothingVisitor,

Author:

Rich Morris Created on 16-Nov-2003

Field Summary

protected CommandVisitor	commandv
protected DeepCopyVisitor	copier
protected NodeFactory	nf Creates new nodes
protected PrintVisitor	pv
protected SimplificationVisitor	simpv
protected SubstitutionVisitor	subv
protected TreeUtils	tu A few utility functions.

Fields inherited from class org.nfunk.jep.JEP

allowAssignment, allowUndeclared, errorList, ev, funTab, implicitMul, numberFactory, opSet, parser, symTab

Constructor Summary

	XJep() Create a new XJep will all the function of JEP plus printing and other features.
	XJep(JEP j) Conversion constructor.
protected	XJep(XJep j) Copy constructions, reuses all the componants of argument.

Method Summary

void	addStandardConstants() Adds the constants pi and e to the parser.
void	addStandardFunctions() Adds the standard functions to the parser.
java.lang.Object	calcVarValue(java.lang.String name) Calculates the value for the variables equation and returns that value.
Node	continueParsing() Continue parsing without re-initilising the stream.
Node	deepCopy(Node node) Returns a deep copy of an expression tree.
java.lang.Object	evaluate(Node node) Evaluates a node.
NodeFactory	getNodeFactory() Returns the node factory, used for constructing trees of Nodes.
PrintVisitor	getPrintVisitor() Returns the PrintVisitor, used for printing equations.
TreeUtils	getTreeUtils() Returns the TreeUtilitities, used for examining properties of nodes.
XJep	newInstance() Creates a new instance of XJep with the same componants as this one.
XJep	newInstance(SymbolTable st) Creates a new instance of XJep with the same componants as this one and the specified symbol table.
Node	preprocess(Node node) Preprocesses an equation to allow the diff and eval operators to be used.
void	print(Node node) Prints the expresion tree on standard output.
void	print(Node node, java.io.PrintStream out) Prints the expresion tree on given stream.
void	println(Node node) Prints the expresion tree on standard output with newline at end.
void	println(Node node, java.io.PrintStream out) Prints the expresion tree on given stream with newline at end.
void	restartParser(java.io.Reader reader) Restarts the parser with the given Reader.
void	restartParser(java.lang.String str) Restarts the parser with the given string.
Node	simplify(Node node) Returns a simplification of an expression tree.
Node	substitute(Node orig, java.lang.String[] names, Node[] replacements) Substitute all occurences of a set of named variable with a set of expression tree.
Node	substitute(Node orig, java.lang.String name, Node replacement) Substitute all occurences of a named variable with an expression tree.
java.lang.String	toString(Node node) Returns a string representation of a expresion tree.

Methods inherited from class org.nfunk.jep.JEP

addComplex, addConstant, addFunction, addVariable, addVariable, addVariable, getAllowAssignment, getAllowUndeclared, getComplexValue, getErrorInfo, getFunctionTable, getImplicitMul, getNumberFactory, getOperatorSet, getParser, getSymbolTable, getTopNode, getTraverse, getValue, getValueAsObject, getVar, getVarValue, hasError, initFunTab, initSymTab, parse, parseExpression, removeFunction, removeVariable, setAllowAssignment, setAllowUndeclared, setImplicitMul, setTraverse, setVarValue

Methods inherited from class java.lang.Object

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

Field Detail

nf

protected NodeFactory nf

Creates new nodes

tu

protected TreeUtils tu

A few utility functions.

copier

protected DeepCopyVisitor copier

subv

protected SubstitutionVisitor subv

simpv

protected SimplificationVisitor simpv

commandv

protected CommandVisitor commandv

pv

protected PrintVisitor pv

Constructor Detail

XJep

public XJep()

Create a new XJep will all the function of JEP plus printing and other features.

XJep

protected XJep(XJep j)

Copy constructions, reuses all the componants of argument.

XJep

public XJep(JEP j)

Conversion constructor. Turns a JEP object into an XJep object.

Parameters:

j -

Method Detail

newInstance

public XJep newInstance()

Creates a new instance of XJep with the same componants as this one. Sub classes should overwrite this method to create objects of the correct type.

newInstance

public XJep newInstance(SymbolTable st)

Creates a new instance of XJep with the same componants as this one and the specified symbol table. Sub classes should overwrite this method to create objects of the correct type.

addStandardFunctions

public void addStandardFunctions()

Description copied from class: JEP

Adds the standard functions to the parser. If this function is not called before parsing an expression, functions such as sin() or cos() would produce an "Unrecognized function..." error. In most cases, this method should be called immediately after the JEP object is created.

Overrides:

addStandardFunctions in class JEP

addStandardConstants

public void addStandardConstants()

Description copied from class: JEP

Adds the constants pi and e to the parser. As addStandardFunctions(), this method should be called immediatly after the JEP object is created.

Overrides:

addStandardConstants in class JEP

deepCopy

public Node deepCopy(Node node)
              throws ParseException

Returns a deep copy of an expression tree.

Throws:

ParseException

evaluate

public java.lang.Object evaluate(Node node)
                          throws java.lang.Exception

Evaluates a node.

Overrides:

evaluate in class JEP

Parameters:

node - the top node of the tree representing the expression.

Returns:

The value of the expression

Throws:

java.lang.Exception - if for some reason the expression could not be evaluated

simplify

public Node simplify(Node node)
              throws ParseException

Returns a simplification of an expression tree.

Throws:

ParseException

preprocess

public Node preprocess(Node node)
                throws ParseException

Preprocesses an equation to allow the diff and eval operators to be used.

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       java.lang.String name,
                       Node replacement)
                throws ParseException

Substitute all occurences of a named variable with an expression tree.

Throws:

ParseException

substitute

public Node substitute(Node orig,
                       java.lang.String[] names,
                       Node[] replacements)
                throws ParseException

Substitute all occurences of a set of named variable with a set of expression tree.

Throws:

ParseException

print

public void print(Node node)

Prints the expresion tree on standard output.

print

public void print(Node node,
                  java.io.PrintStream out)

Prints the expresion tree on given stream.

println

public void println(Node node)

Prints the expresion tree on standard output with newline at end.

println

public void println(Node node,
                    java.io.PrintStream out)

Prints the expresion tree on given stream with newline at end.

toString

public java.lang.String toString(Node node)

Returns a string representation of a expresion tree.

getNodeFactory

public NodeFactory getNodeFactory()

Returns the node factory, used for constructing trees of Nodes.

getTreeUtils

public TreeUtils getTreeUtils()

Returns the TreeUtilitities, used for examining properties of nodes.

getPrintVisitor

public PrintVisitor getPrintVisitor()

Returns the PrintVisitor, used for printing equations.

calcVarValue

public java.lang.Object calcVarValue(java.lang.String name)
                              throws java.lang.Exception

Calculates the value for the variables equation and returns that value. If the variable does not have an equation just return its value.

Throws:

java.lang.Exception

continueParsing

public Node continueParsing()
                     throws ParseException

Continue parsing without re-initilising the stream. Allows renetrancy of parser so that strings like "x=1; y=2; z=3;" can be parsed. When a semi colon is encountered parsing finishes leaving the rest of the string unparsed. Parsing can be resumed from the current position by using this method. For example

 XJep j = new XJep();
 j.restartParser("x=1;y=2; z=3;");
 Node node;
 try {
 while((node = j.continueParsing())!=null) {
    j.println(node);
 } }catch(ParseException e) {}
 

Returns:

top node of equation parsed to date or null if empty equation

Throws:

ParseException

See Also:

restartParser(java.lang.String)

restartParser

public void restartParser(java.lang.String str)

Restarts the parser with the given string.

Parameters:

str - String containing a sequence of equations separated by semi-colons.

See Also:

continueParsing()

restartParser

public void restartParser(java.io.Reader reader)

Restarts the parser with the given Reader.

Parameters:

reader - Reader from which equations separated by semi-colons will be read.

See Also:

continueParsing()