/*
 * Copyright (c) 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 java.io.PrintStream;
import common.Util;
import common.MapWithPreimages;
import common.HashMapWithPreimages;

public class DefaultEvalContext implements EvalContext {
    

    public DefaultEvalContext(PartialWorld world) {
	this.world = world;
    }

    

    public DefaultEvalContext(PartialWorld world, boolean errorIfUndet) {
	this.world = world;
	this.errorIfUndet = errorIfUndet;
    }

    public Object getValue(BasicVar var) {
	Object value = world.getValue(var);
	if (value == null) {
	    handleMissingVar(var);
	}
	return value;
    }

    public ObjectSet getSatisfiers(NumberVar popApp) {
	if (getValue(popApp) != null) { // note that we use our getValue method
	    return world.getSatisfiers(popApp);
	}

	handleMissingVar(popApp);
	return null;
    }

    public NumberVar getPOPAppSatisfied(Object obj) {
	// might want to report invalid objects
	return world.getPOPAppSatisfied(obj);
    }

    public boolean usesIdentifiers(Type type) {
	return world.getIdTypes().contains(type);
    }

    public Boolean objectExists(Object obj) {
	if (obj instanceof NonGuaranteedObject) {
	    NonGuaranteedObject ngObj = (NonGuaranteedObject) obj;
	    NumberVar nv = ngObj.getNumberVar();
	    Integer varValue = (Integer) getValue(nv); 
	    if (varValue == null) {
		return null;
	    }
	    return Boolean.valueOf(ngObj.getNumber() <= varValue.intValue());
	}

	return Boolean.TRUE;
    }

    public Object getLogicalVarValue(LogicalVar var) {
	if (assignment == null) {
	    return null;
	}
	return assignment.get(var);
    }

    public Set getLogicalVarValues() {
	if (assignment == null) {
	    return Collections.EMPTY_SET;
	}
	return assignment.valueSet();
    }

    public String getAssignmentStr() {
	if (assignment == null) {
	    return Collections.EMPTY_MAP.toString();
	}
	return assignment.toString();
    }

    public void assign(LogicalVar var, Object value) {
	if (assignment == null) {
	    assignment = new HashMapWithPreimages();
	}
	assignment.put(var, value);
    }

    public void assignTuple(LogicalVar[] vars, Object[] values) {
	if (assignment == null) {
	    assignment = new HashMapWithPreimages();
	}
	for (int i = 0; i < vars.length; ++i) {
	    assignment.put(vars[i], values[i]);
	}
    }

    public void unassign(LogicalVar var) {
	if (assignment != null) {
	    assignment.remove(var);
	}
    }

    public void unassignTuple(LogicalVar[] vars) {
	if (assignment != null) {
	    for (int i = 0; i < vars.length; ++i) {
		assignment.remove(vars[i]);
	    }
	}
    }

    

    public void pushEvaluee(Object evaluee) {
	if (evaluees == null) {
	    evaluees = new LinkedList();
	}
	evaluees.addLast(evaluee);
    }

    

    public void popEvaluee() {
	if ((evaluees == null) || evaluees.isEmpty()) {
	    throw new IllegalStateException("Evaluee stack is empty.");
	}
	evaluees.removeLast();
    }

    

    public void printEvalTrace(PrintStream s) {
	if (evaluees != null) {
	    for (Iterator iter = evaluees.iterator(); iter.hasNext(); ) {
		s.println(iter.next());
	    }
	}
    }

    

    protected void handleMissingVar(BayesNetVar var) {
	if (errorIfUndet) {
	    System.err.println("Error with evaluation trace:");
	    printEvalTrace(System.err);
	    Util.fatalError("Variable " + var + " is not instantiated.");
	}
    }

    protected PartialWorld world;

    protected boolean errorIfUndet = false;

    private MapWithPreimages assignment;
    private LinkedList evaluees;
}

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