/*
 * Copyright (c) 2005, 2006, Regents of the University of California
 * All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 * * Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in
 *   the documentation and/or other materials provided with the
 *   distribution.  
 *
 * * Neither the name of the University of California, Berkeley nor
 *   the names of its contributors may be used to endorse or promote
 *   products derived from this software without specific prior 
 *   written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package blog;

import java.util.*;
import common.HashMapDiff;

public class UniversalFormula extends Formula{

    

    public UniversalFormula( String varName, Type varType, Formula cond ){
	var = new LogicalVar(varName, varType);
	this.cond = cond;
    }

    public UniversalFormula(LogicalVar var, Formula cond) {
	this.var = var;
	this.cond = cond;
    }

    

    public LogicalVar getLogicalVariable() {
	return var;
    }

    

    public Type getType() {
	return var.getType();
    }

    

    public Formula getCond() {
	return cond;
    }

    public Object evaluate(EvalContext context) {
	context.pushEvaluee(this);

	ObjectSet counterexamples 
	    = getCounterexampleSpec().elementSet(context);
	Boolean result = null;
	if (counterexamples.canDetermineIsEmpty()) {
	    result = Boolean.valueOf(counterexamples.isEmpty());
	    if (counterexampleSpec.dependsOnIdOrder(context)) {
		System.out.println
		    ("Warning: Short-circuiting an iteration that depends on "
		     + "order of object identifiers, while evaluating " 
		     + this + ".  MCMC states may define overlapping events.");
	    }
	}

	context.popEvaluee();
	return result;
    }

    public boolean containsRandomSymbol() {
	return true; // the type symbol
    }

    

    public Formula getStandardForm() {
	return new UniversalFormula(var, cond.getStandardForm());
    }

    

    protected Formula getEquivToNegationInternal() {
	return new ExistentialFormula(var, new NegFormula(cond));
    }

    public List getSubformulas() {
	return Collections.singletonList(cond);
    }

    public Set getFreeVars() {
	Set freeVars = new HashSet(cond.getFreeVars());
	freeVars.remove(var);
	return Collections.unmodifiableSet(freeVars);
    }

    public boolean isQuantified() {
	return true;
    }

    public boolean checkTypesAndScope(Model model, Map scope) {
	Map extendedScope = new HashMapDiff(scope);
	extendedScope.put(var.getName(), var);
	return cond.checkTypesAndScope(model, extendedScope);
    }

    

    public int compile(LinkedHashSet callStack) {
	callStack.add(this);
	int errors = cond.compile(callStack);
	if (errors > 0) {
	    return errors;
	}

	counterexampleSpec = new CompiledSetSpec(var, new NegFormula(cond));
	callStack.remove(this);
	return 0;
    }

    public Set getSatisfiersIfExplicit(EvalContext context, 
				       LogicalVar subject,
				       GenericObject genericObj) {
	List varValuesToCheck = new ArrayList();
	Set explicitCondSat = null;

	// We look at values of the quantified variable that might
	// make cond false.  Values that make cond true regardless of
	// the value of subject are not interesting because they don't
	// give us an explicit satisfier set.  We use an unfiltered
	// iterator because the set of quantified-variable values that
	// make cond false often depends on the value of subject.  We
	// hope the ObjGenGraphs used for the unfiltered iterator
	// don't use subject (if they do, canDetermineNext will return false).
	ObjectIterator varValueIter 
	    = getCounterexampleSpec().unfilteredIterator(context);
	while (varValueIter.hasNext()) {
	    Object varValue = varValueIter.next();
	    context.assign(var, varValue);
	    Set condSat = cond.getSatisfiersIfExplicit
		(context, subject, genericObj);
	    if ((condSat != null) && (condSat != Formula.ALL_OBJECTS)) {
		explicitCondSat = condSat;
		break; // we have an explicit satisifer set
	    }

	    if (condSat != Formula.ALL_OBJECTS) {
		varValuesToCheck.add(varValue);
	    }
	}
	context.unassign(var);
	if (!varValueIter.canDetermineNext()) {
	    return null;
	}
	
	if (explicitCondSat != null) {
	    // For some value of the quantified variable, we have 
	    // an explicit set of subject values that make cond true.  
	    // The formula satisfiers are those subject values that 
	    // make cond true for all the other quantified variable 
	    // values too. 

	    if (explicitCondSat.isEmpty()) {
		return explicitCondSat; // no need to filter
	    }
	    
	    // Get the rest of the variable values
	    while (varValueIter.hasNext()) {
		varValuesToCheck.add(varValueIter.next());
	    }
	    if (!varValueIter.canDetermineNext()) {
		return null;
	    }

	    Set satisfiers = new LinkedHashSet();
	    for (Iterator subjectValIter = explicitCondSat.iterator(); 
		     subjectValIter.hasNext(); ) {
		Object subjectVal = subjectValIter.next();
		context.assign(subject, subjectVal);
		if (trueWithAllVarValues(context, varValuesToCheck)) {
		    satisfiers.add(subjectVal);
		}
	    }
	    context.unassign(subject);
	    return satisfiers;
	}

	// We did not get an explicit satisfier set for any value of 
	// the quantified variable.  Still, if all the quantified 
	// variable values we looked at made cond true regardless of 
	// the subject value, we can return Formula.ALL_OBJECTS.  
	if (varValuesToCheck.isEmpty()) {
	    return Formula.ALL_OBJECTS;
	}
	return null;
    }

    public ArgSpec getSubstResult(Substitution subst, 
				  Set<LogicalVar> boundVars) {
	boundVars = new HashSet<LogicalVar>(boundVars);
	boundVars.add(var);
	return new UniversalFormula
	    (var, (Formula) cond.getSubstResult(subst, boundVars));
    }

    public String toString() {
	return ("forall " + var.getType() + " " + var.getName() 
		+ " (" + cond + ")");
    }

    public boolean equals(Object o) {
	if (o instanceof UniversalFormula) {
	    UniversalFormula other = (UniversalFormula) o;
	    return (var.equals(other.getLogicalVariable())
		    && cond.equals(other.getCond()));
	}
	return false;
    }

    public int hashCode() {
	return (getClass().hashCode() ^ var.hashCode() ^ cond.hashCode());
    }

    

    protected CompiledSetSpec getCounterexampleSpec() {
	if (counterexampleSpec == null) {
	    compile(new LinkedHashSet());
	}
	return counterexampleSpec;
    }

    private boolean trueWithAllVarValues(EvalContext context, 
					 Collection varValues) {
	boolean allTrue = true;
	for (Iterator iter = varValues.iterator(); iter.hasNext(); ) {
	    Object varValue = iter.next();
	    context.assign(var, varValue);
	    Boolean condValue = (Boolean) cond.evaluate(context);
	    if ((condValue == null) || !condValue.booleanValue()) {
		allTrue = false;
		break;
	    }
	}
	context.unassign(var);
	return allTrue;
    }
    
    LogicalVar var;
    Formula cond;

    CompiledSetSpec counterexampleSpec;
} 

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