at.jku.risc.stout.urmc.data

Class TermNode

java.lang.Object

at.jku.risc.stout.urmc.util.Printable

at.jku.risc.stout.urmc.data.TermNode

public class TermNode
extends Printable

A term node consists of a TermAtom and a Hedge.

Author:

Alexander Baumgartner

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	TermNode.TraverseCallBack This class may be used to traverse a term tree and execute an arbitrary operation on every node.

Field Summary

Fields

Modifier and Type	Field and Description
static TermNode	EMPTY

Constructor Summary

Constructors

Constructor and Description
TermNode(TermAtom atom, Hedge hedge) Instantiates a new term node.

Method Summary

Methods

Modifier and Type	Method and Description
TermNode	apply(Map<Variable,TermNode> sigma) Applies a substitution recursively and returns the new TermNode.
TermNode	copy()
boolean	equals(Object other)
TermAtom	getAtom()
Hedge	getHedge()
int	hashCode()
boolean	isNullAtom() Tests whether the atom of this term node is the null atom.
boolean	occurs(TermAtom atomOcc)
void	print(Writer out)
TermNode	replaceHole(Hedge plugIn) Replaces the hole in this context with the given hedge.
void	setAtom(TermAtom atom) Null values are transformed to unique objects which represent the null value.
void	setHedge(Hedge hedge) Null values are transformed to unique objects which represent the null value.
TermNode	substitute(Variable from, TermNode to) Substitutes one Variable by a TermNode recursively and returns the new TermNode.
String	toString()
boolean	traverse(TermNode.TraverseCallBack callBack) Traverses the term tree and executes the callback function at every node.

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Field Detail

EMPTY

public static final TermNode EMPTY

Constructor Detail

TermNode

public TermNode(TermAtom atom,
        Hedge hedge)

Instantiates a new term node. null values are transformed to unique objects which represent the null value. So that no NullPointerException can occur.

See Also:

TermAtom.nullAtom, Hedge.nullHedge

Method Detail

apply

public TermNode apply(Map<Variable,TermNode> sigma)

Applies a substitution recursively and returns the new TermNode.

copy

public TermNode copy()

equals

public boolean equals(Object other)

Overrides:

equals in class Object

getAtom

public TermAtom getAtom()

getHedge

public Hedge getHedge()

hashCode

public int hashCode()

Overrides:

hashCode in class Object

isNullAtom

public boolean isNullAtom()

Tests whether the atom of this term node is the null atom.

occurs

public boolean occurs(TermAtom atomOcc)

print

public void print(Writer out)
           throws IOException

Specified by:

print in class Printable

Throws:

IOException

replaceHole

public TermNode replaceHole(Hedge plugIn)

Replaces the hole in this context with the given hedge. Returns null if no hole has been found, otherwise the new TermNode will be returned.

setAtom

public void setAtom(TermAtom atom)

Null values are transformed to unique objects which represent the null value. So that no NullPointerException can occur.

See Also:

TermAtom.nullAtom

setHedge

public void setHedge(Hedge hedge)

Null values are transformed to unique objects which represent the null value. So that no NullPointerException can occur.

See Also:

Hedge.nullHedge

substitute

public TermNode substitute(Variable from,
                  TermNode to)

Substitutes one Variable by a TermNode recursively and returns the new TermNode.

toString

public String toString()

Overrides:

toString in class Printable

traverse

public boolean traverse(TermNode.TraverseCallBack callBack)

Traverses the term tree and executes the callback function at every node.

See Also:

TermNode.TraverseCallBack