vec_math
Class Node<E>

java.lang.Object
  vec_math.Node<E>

Direct Known Subclasses:

StringNode

public abstract class Node<E>
extends Object

A node in a parser scheme. The implementation is very basic and does only define principle methods. The concrete parsing of some object into the operator of the node and it sub-nodes must be implemnted by concrete subclasses.

Field Summary

private boolean	isParsed True if the node has been successfully parsed.
private int	level The level of the node.
private Node<E>	parent The parent of the node.
private E	parse The object this node can be parsed out.
private Node<E>[]	sub The sub-nodes.
private Operator<E>	tie The operator of this node.
private E	value The value of the node.

Constructor Summary

protected	Node(E description) A basic constructor for a root node.
protected	Node(Node<E> superior, E description, int layer) A basic constructor for sub nodes.

Method Summary

boolean	equals(Node that) Compares to nodes for equality.
int	getLevel() Returns the level of this node.
Node<E>	getParent() Returns the parent of this node.
E	getParseSource() Returns the object this node should be parsed from.
Node<E>[]	getSub() Returns the sub nodes.
Node<E>	getSubAt(int index) Returns a single sub node.
int	getSubNodeNumber() Returns the number of sub nodes.
Operator<E>	getTie() Returns the node operator.
E	getValue() Returns the value of this node.
Set<E>	getVariables() Uses the parsed node to dive recursively into all subnodes and piles up a variable list.
boolean	isFinal() Returns true if this node is a final node.
boolean	isParsed() Returns true if this node has already been parsed.
boolean	isRoot() Returns true if this node is the root node.
protected boolean	isVariable(E arg) Return true if the value object is a variable.
void	parse() Parses this node.
void	parse(E source) Parses the object to derive sub nodes and node operator if any.
protected abstract Operator<E>	parseOperator(E src) Parses the source for this nodes operator.
protected abstract Node<E>[]	parseSub(E src) Parses the source for this nodes sub-nodes.
protected void	setParse(boolean value) Sets the parsed flag.
protected void	setParseSource(E source) Sets the object this node should be parsed from.
protected void	setSub(Node<E>[] subnodes) Sets the sub nodes.
protected void	setTie(Operator<E> op) Sets the node operator.
void	setValue(E result) Sets the value of this node.
String	toString() A String representation of this Node.
protected void	traceVariable(Set<E> accu, Node<E> node) Stores the value of this node in the argument set if final.

Methods inherited from class java.lang.Object

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

Field Detail

parent

private Node<E> parent

The parent of the node.

tie

private Operator<E> tie

The operator of this node.

sub

private Node<E>[] sub

The sub-nodes. The length of the array corresponds to the number of arguments of the operator of this node.

level

private int level

The level of the node. The root node has level 0.

parse

private E parse

The object this node can be parsed out.

value

private E value

The value of the node.

isParsed

private boolean isParsed

True if the node has been successfully parsed.

Constructor Detail

Node

protected Node(E description)

A basic constructor for a root node. Note that parsing must be explicitly initiated via a call to parse.

Node

protected Node(Node<E> superior,
               E description,
               int layer)

A basic constructor for sub nodes. Note that parsing must be explicitly initiated via a call to parse.

Method Detail

getTie

public Operator<E> getTie()

Returns the node operator.

setTie

protected void setTie(Operator<E> op)

Sets the node operator.

setSub

protected void setSub(Node<E>[] subnodes)

Sets the sub nodes.

getSub

public Node<E>[] getSub()
                 throws ParseException

Returns the sub nodes. Throws a ParseException if the node has not successfully parsed prior to the call to this method.

Throws:

ParseException

getSubAt

public Node<E> getSubAt(int index)
                 throws ParseException

Returns a single sub node. Throws a ParseException if the node has not successfully parsed prior to the call to this method.

Throws:

ParseException

getSubNodeNumber

public int getSubNodeNumber()
                     throws ParseException

Returns the number of sub nodes. This number should be identical to the number of operands the operator of this node requires. Throws a ParseException if the node has not successfully parsed prior to the call to this method.

Throws:

ParseException

isRoot

public boolean isRoot()

Returns true if this node is the root node. Simple checks if the node level equals zero.

isFinal

public boolean isFinal()

Returns true if this node is a final node. A final node consists of a single value without any operators. Throws a ParseException if the node has not successfully parsed prior to the call to this method.

getLevel

public int getLevel()

Returns the level of this node. Zero denotes the root node.

getParent

public Node<E> getParent()

Returns the parent of this node. Null is returned if this node is the root node.

getParseSource

public E getParseSource()

Returns the object this node should be parsed from.

setParseSource

protected void setParseSource(E source)

Sets the object this node should be parsed from.

getValue

public E getValue()

Returns the value of this node.

setValue

public void setValue(E result)

Sets the value of this node.

parse

public void parse()
           throws ParseException

Parses this node. Throws a ParseException if the parsable object had not been set prior to the call to this method.

Throws:

ParseException

isParsed

public boolean isParsed()

Returns true if this node has already been parsed.

setParse

protected void setParse(boolean value)

Sets the parsed flag.

parse

public void parse(E source)
           throws ParseException

Parses the object to derive sub nodes and node operator if any. Subclasses can override this class if performance can be increased by simultanously scanning for operator and sub-nodes. In the latter case the subclass should either call this class's parse method or setParse(boolean) to indicate successful parsing.

Throws:

ParseException

getVariables

public Set<E> getVariables()

Uses the parsed node to dive recursively into all subnodes and piles up a variable list.

traceVariable

protected void traceVariable(Set<E> accu,
                             Node<E> node)

Stores the value of this node in the argument set if final. Otherwise dives into subnodes. As for the general contract of a set, the variable is stored in the set only once.

isVariable

protected boolean isVariable(E arg)

Return true if the value object is a variable. The default behaviour is to always return true unless the argument is null. Subclasses should interfere here.

equals

public boolean equals(Node that)

Compares to nodes for equality. The default implementation returns true if the level and the parse object are equal.

toString

public String toString()

A String representation of this Node. Simply calls the toString() method on the parse object.

Overrides:

toString in class Object

parseOperator

protected abstract Operator<E> parseOperator(E src)
                                      throws ParseException

Parses the source for this nodes operator.

Throws:

ParseException

parseSub

protected abstract Node<E>[] parseSub(E src)
                               throws ParseException

Parses the source for this nodes sub-nodes.

Throws:

ParseException