org.semanticweb.kaon2.api.rules
Interface Literal

public interface Literal

Represents a literal in the rule. A literal consists of a predicate, a pattern representing the variable names or contstants and a flag determining whether the literal is negated.

Method Summary

java.lang.Object	accept(KAON2Visitor visitor) Accepts a visitor for this object.
boolean	containsVariable(Variable variable) Returns true if this literal contains supplied variable.
Term	getArgument(int argumentIndex) Returns the argument at given position.
Constant	getArgumentConstant(int argumentIndex) Returns the constant of the given argument.
Term[]	getArguments() Returns the array of argument terms.
Variable	getArgumentVariable(int argumentIndex) Returns the variable at given position.
int	getArity() Returns the arity of the literal.
Predicate	getPredicate() Returns the predicate of this literal.
boolean	isArgumentBoundToConstant(int argumentIndex) Reutrns true if given argument is bound to a constant.
boolean	isArgumentBoundToVariable(int argumentIndex) Reutrns true if given argument is bound to a variable.
boolean	isPositive() Returns true if this literal is positive (with respect to non-monotonic negation).
void	toString(java.lang.StringBuffer buffer, Namespaces namespaces) Writes this entity to the supplied sting buffer.

Method Detail

isPositive

boolean isPositive()

Returns true if this literal is positive (with respect to non-monotonic negation).

Returns:

true is this literal is positive

getPredicate

Predicate getPredicate()

Returns the predicate of this literal.

Returns:

the predicate

getArguments

Term[] getArguments()

Returns the array of argument terms. This object is not owned by the literal (i.e. it can be changed without affecthing this literal).

Returns:

the argument terms

getArity

int getArity()

Returns the arity of the literal.

Returns:

the arity of the literal

isArgumentBoundToVariable

boolean isArgumentBoundToVariable(int argumentIndex)

Reutrns true if given argument is bound to a variable.

Parameters:

argumentIndex - the index of the argument

Returns:

true if the argument is bound to a variable

isArgumentBoundToConstant

boolean isArgumentBoundToConstant(int argumentIndex)

Reutrns true if given argument is bound to a constant.

Parameters:

argumentIndex - the index of the argument

Returns:

true if the argument is bound to a constant

getArgument

Term getArgument(int argumentIndex)

Returns the argument at given position.

Parameters:

argumentIndex - the index of the argument

Returns:

the term at given position

getArgumentVariable

Variable getArgumentVariable(int argumentIndex)

Returns the variable at given position.

Parameters:

argumentIndex - the index of the argument

Returns:

the variable at given position (or null if given position is not bound to a variable)

getArgumentConstant

Constant getArgumentConstant(int argumentIndex)

Returns the constant of the given argument.

Parameters:

argumentIndex - the index of the argument

Returns:

the constant (of null if the argument is not bound to a constant)

containsVariable

boolean containsVariable(Variable variable)

Returns true if this literal contains supplied variable.

Parameters:

variable - the variable

Returns:

true if this literal contains supplied variable

toString

void toString(java.lang.StringBuffer buffer,
              Namespaces namespaces)

Writes this entity to the supplied sting buffer.

Parameters:

buffer - the buffer

namespaces - the namespaces object

accept

java.lang.Object accept(KAON2Visitor visitor)

Accepts a visitor for this object.

Parameters:

visitor - the visitor for this object

Returns:

the return value of the visitor (can be null)