TrueFormula.html

TrueFormula.java

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package blog;

import java.util.*;

A Formula consisting of just the zero-ary logical operator "true", which is true in every world under every assignment.


public class TrueFormula extends Formula {

A canonical instance of TrueFormula.


    public static final TrueFormula TRUE = new TrueFormula();

Creates a new TrueFormula.


    public TrueFormula() {
    }

    public Object evaluate(EvalContext context) {
	return Boolean.TRUE;
    }

The standard form of the formula "true" is an empty conjunction, which is always true.


    public Formula getStandardForm() {
	return new ConjFormula(Collections.EMPTY_LIST);
    }

A formula equivalent to the negation of "true" is the empty disjunction, which is always false.


    protected Formula getEquivToNegationInternal() {
	return new DisjFormula(Collections.EMPTY_LIST);
    }

The CNF form of TrueFormula has no conjuncts.


    public ConjFormula getPropCNF() {
	return new ConjFormula(Collections.EMPTY_LIST);
    }

The DNF form of TrueFormula has just one disjunct, which is an empty conjunction.


    public DisjFormula getPropDNF() {
	return new DisjFormula(new ConjFormula(Collections.EMPTY_LIST));
    }

    public Set getSatisfiersIfExplicit(EvalContext context, 
				       LogicalVar subject,
				       GenericObject genericObj) {
	return Formula.ALL_OBJECTS;
    }

    public Set getNonSatisfiersIfExplicit(EvalContext context,
					  LogicalVar subject,
					  GenericObject genericObj) {
	return Collections.EMPTY_SET;
    }

Any two instances of TrueFormula are equal.


    public boolean equals(Object o) {
	return (o instanceof TrueFormula);
    }

    public int hashCode() {
	return Boolean.TRUE.hashCode();
    }

Returns the string "true".


    public String toString() {
	return "true";
    }

    public boolean checkTypesAndScope(Model model, Map scope) {
	return true;
    }

    public ArgSpec getSubstResult(Substitution subst, 
				  Set<LogicalVar> boundVars) {
	return this;
    }
}

This file was generated on Tue Jun 08 17:53:36 PDT 2010 from file TrueFormula.java
by the ilog.language.tools.Hilite Java tool written by Hassan Aït-Kaci