ubc.cs.JLog.Terms
Class jObject

java.lang.Object
  extended by ubc.cs.JLog.Foundation.jType
      extended by ubc.cs.JLog.Terms.jTerm
          extended by ubc.cs.JLog.Terms.jObject
All Implemented Interfaces:
iType, iUnifiable, iConsultable, iName, iTerm, iValue

public class jObject
extends jTerm

This is the term used to reference Java objects. It is not created by the parser, instead special builtin predicates which require such references provide a constructor predicate which create a jObject instance.

Author:
Glendon Holst

Field Summary
protected  java.lang.Object value
           
 
Fields inherited from class ubc.cs.JLog.Foundation.jType
type
 
Fields inherited from interface ubc.cs.JLog.Terms.iTerm
EQUAL, GREATER_THAN, LESS_THAN
 
Fields inherited from interface ubc.cs.JLog.Foundation.iType
TYPE_ARITHMETIC, TYPE_ATOM, TYPE_BUILTINPREDICATE, TYPE_COMMAND, TYPE_COMPARE, TYPE_COMPOUND, TYPE_CONS, TYPE_IF, TYPE_INTEGER, TYPE_LIST, TYPE_NULLLIST, TYPE_NUMERICCOMPARE, TYPE_OBJECT, TYPE_OPERATOR, TYPE_OR, TYPE_ORPREDICATE, TYPE_PREDICATE, TYPE_PREDICATETERMS, TYPE_REAL, TYPE_TYPE, TYPE_UNARYARITHMETIC, TYPE_UNARYOPERATOR, TYPE_UNDEFINED, TYPE_VARIABLE
 
Constructor Summary
jObject(java.lang.Object v)
           
 
Method Summary
protected  int compare(jTerm term, boolean first_call, boolean var_equal)
          The private member function for term comparision.
 jTerm copy(jVariableRegistry vars)
          Internal member function which creates a copy of this term.
 jTerm duplicate(jVariable[] vars)
          Creates a complete and entirely independant duplicate of this term.
 void enumerateVariables(jVariableVector v, boolean all)
          Adds variables belonging to this term (or belonging to any sub-part of this term) to the jVariableVector
 boolean equivalence(jTerm term, jEquivalenceMapping v)
          The public interface for evaluating term equivalence (i.e., structural similarity).
 java.lang.String getName()
          Returns the name of this instance.
 java.lang.Object getObjectReference()
           
 void registerVariables(jVariableVector v)
          Adds all variables belonging to this term (or belonging to any sub-part of this term) to the jUnifiedVector Should be called during the consultation phase by rules for their owned terms both head and base.
 java.lang.String toString(boolean usename)
          Produces a string identifying this term, suitable for display to the console.
 boolean unify(jTerm term, jUnifiedVector v)
          Determines if this instance and term unify.
 
Methods inherited from class ubc.cs.JLog.Terms.jTerm
compare, consult, consultReset, copy, getTerm, getValue, isConsultNeeded, registerUnboundVariables, requiresCompleteVariableState, toString
 
Methods inherited from class ubc.cs.JLog.Foundation.jType
getType, objectToString
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

value

protected java.lang.Object value
Constructor Detail

jObject

public jObject(java.lang.Object v)
Method Detail

getName

public java.lang.String getName()
Description copied from interface: iName
Returns the name of this instance.

Specified by:
getName in interface iName
Specified by:
getName in interface iTerm
Overrides:
getName in class jTerm
Returns:
String containing name of this instance.

getObjectReference

public java.lang.Object getObjectReference()

compare

protected int compare(jTerm term,
                      boolean first_call,
                      boolean var_equal)
Description copied from class: jTerm
The private member function for term comparision. Compares this instance to the provided jTerm. sub-classes must override.

Specified by:
compare in class jTerm
Parameters:
term - the jTerm to compare with this instance of jTerm. if term is an unknown type then, if first_call is true, call term.compare(this,false) and return the negative result, otherwise return EQUAL.
first_call - true if just invoked by public compare member function. false otherwise.
var_equal - if var_equal is true, then unbound variables are considered equal. var_equal = false is standard prolog behavior.
Returns:
LESS_THAN if this instance is less than term, EQUAL if the two terms are equal, and GREATER_THAN if this instance is greater than term.

equivalence

public boolean equivalence(jTerm term,
                           jEquivalenceMapping v)
Description copied from interface: iTerm
The public interface for evaluating term equivalence (i.e., structural similarity).

Specified by:
equivalence in interface iTerm
Specified by:
equivalence in class jTerm
Parameters:
term - the jTerm to compare with this instance of jTerm.
v - v is the collection of equivalent variable pairs found. It should be empty when first calling this function.
Returns:
true if this instance is equivalent to term, false otherwise.

unify

public boolean unify(jTerm term,
                     jUnifiedVector v)
Description copied from interface: iUnifiable
Determines if this instance and term unify. Every variable which was previously unbound, but which becomes bound during the unification must register itself with the jUnifiedVector. It is the callers responsibility to deal with the unified vector.

Specified by:
unify in interface iUnifiable
Specified by:
unify in interface iTerm
Specified by:
unify in class jTerm
Parameters:
term - the term to unify with this instance.
v - the vector of variables bound during unification. Even if unification fails, this vector may contain recently bound vectors. This parameter is used to as output to the caller, not as input for unify.
Returns:
true if unification succeeded, false otherwise.

registerVariables

public void registerVariables(jVariableVector v)
Description copied from class: jTerm
Adds all variables belonging to this term (or belonging to any sub-part of this term) to the jUnifiedVector Should be called during the consultation phase by rules for their owned terms both head and base. all variables encountered should be unbound. After call, this term should not be modified in any way.

Specified by:
registerVariables in interface iTerm
Specified by:
registerVariables in class jTerm
Parameters:
v - The jUnifiedVector where variables are added to. This parameter is used to as output to the caller, not as input.

enumerateVariables

public void enumerateVariables(jVariableVector v,
                               boolean all)
Description copied from class: jTerm
Adds variables belonging to this term (or belonging to any sub-part of this term) to the jVariableVector

Specified by:
enumerateVariables in interface iTerm
Specified by:
enumerateVariables in class jTerm
Parameters:
v - The jVariabeVector where variables are added to. This parameter is used to as output to the caller, not as input.
all - If true, then all variables should register, otherwise only add non-existentially qualified variables.

duplicate

public jTerm duplicate(jVariable[] vars)
Description copied from class: jTerm
Creates a complete and entirely independant duplicate of this term. User should call only for terms for which registerVariables has already been invoked. Within duplicate, any other calls to duplicate should pass along the same vars array produced by registerVariables since the same duplication path previously taken by registerVariables should be taken by duplicate. This call is designed only for terms which belong to rules and are templates for instantiation. Any variables in the term should be unbound. As implied by the modification restrictions on registerVariables, terms and their children cannot change (especially during call!)

Specified by:
duplicate in interface iTerm
Specified by:
duplicate in class jTerm
Parameters:
vars - The user passes in a duplicate of the variable vector produced from the previous call to registerVariables. vars is produced from the jVariableVector by creating a single duplicate variable for each variable. Since this is created in the same order as the registerVariables, it is now efficient for jVariables to return their unique duplicate.
Returns:
jTerm which is an instantiated duplicate of this term.

copy

public jTerm copy(jVariableRegistry vars)
Description copied from class: jTerm
Internal member function which creates a copy of this term. This member function is designed to duplicate a term, but without the restrictions of the duplicate function. Should only be invoked by copy() or other copy(vars). Should only invoke other copy(vars) functions. Bound variables should return a copy of the bound term.

Specified by:
copy in interface iTerm
Specified by:
copy in class jTerm
Parameters:
vars - The registry of variables and their duplicates. Initially this is empty. As variables generate copies, they add themselves and their copy to the jVariableRegistry, and this is output from the function call. Any further calls with the same vars ensures that the same variable (in a different term) returns the same copy.
Returns:
jTerm which is an instantiated copy of this term.

toString

public java.lang.String toString(boolean usename)
Description copied from class: jTerm
Produces a string identifying this term, suitable for display to the console. param usename determines whether to display variables by name or identity. false is the default for displaying the term, true for displaying this term in a user query.

Specified by:
toString in interface iTerm
Specified by:
toString in class jTerm
Returns:
String which is a textual representation of this term.