/* A criterion to constrain a guard of a transition in an FSM or a Ptera
controller.
Copyright (c) 2008-2009 The Regents of the University of California.
All rights reserved.
Permission is hereby granted, without written agreement and without
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*/
package ptolemy.actor.gt.ingredients.criteria;
import ptolemy.actor.gt.GTIngredientElement;
import ptolemy.actor.gt.GTIngredientList;
import ptolemy.actor.gt.ValidationException;
import ptolemy.data.BooleanToken;
import ptolemy.data.expr.Variable;
import ptolemy.domains.modal.kernel.Transition;
import ptolemy.kernel.util.InternalErrorException;
import ptolemy.kernel.util.NamedObj;
//////////////////////////////////////////////////////////////////////////
//// GuardCriterion
/**
A criterion to constrain a guard of a transition in an FSM or a Ptera
controller.
@author Thomas Huining Feng
@version $Id$
@since Ptolemy II 8.0
@Pt.ProposedRating Yellow (tfeng)
@Pt.AcceptedRating Red (tfeng)
*/
public class GuardCriterion extends Criterion {
/** Construct a criterion within the given list as its owner. All elements
* are enabled and are initialized to empty at the beginning.
*
* @param owner The list as the owner of the constructed GTIngredientList.
*/
public GuardCriterion(GTIngredientList owner) {
this(owner, "");
}
/** Construct a criterion within the given list as its owner and initialize
* all the elements with the given values, which are a string encoding of
* those elements. All elements are enabled at the beginning.
*
* @param owner The list as the owner of the constructed GTIngredientList.
* @param values The string encoding of the values of the elements.
*/
public GuardCriterion(GTIngredientList owner, String values) {
super(owner, 1);
setValues(values);
}
/** Get the array of elements defined in this GTIngredient.
*
* @return The array of elements.
*/
public GTIngredientElement[] getElements() {
return _ELEMENTS;
}
/** Get the value of the index-th elements.
*
* @param index The index.
* @return The value.
* @see #setValue(int, Object)
*/
public Object getValue(int index) {
switch (index) {
case 0:
return _guardValue;
default:
return null;
}
}
/** Get a string that describes the values of all the elements.
*
* @return A string that describes the values of all the elements.
* @see #setValues(String)
*/
public String getValues() {
StringBuffer buffer = new StringBuffer();
_encodeStringField(buffer, 0, _guardValue);
return buffer.toString();
}
/** Check whether this GTIngredient is applicable to the object.
*
* @param object The object.
* @return true if this GTIngredient is applicable; false otherwise.
*/
public boolean isApplicable(NamedObj object) {
return super.isApplicable(object) && object instanceof Transition;
}
/** Return whether this criterion can check the given object.
*
* @param object The object.
* @return true if the object can be checked.
*/
public boolean match(NamedObj object) {
Variable guardVariable = null;
try {
guardVariable = new Variable(object, object
.uniqueName("guardVariable"));
String guard = ((Transition) object).guardExpression
.getExpression();
String guardTester = "(" + guard + ") == (" + _guardValue + ")";
guardVariable.setExpression(guardTester);
BooleanToken result = (BooleanToken) guardVariable.getToken();
return result.booleanValue();
} catch (Exception e) {
return false;
} finally {
if (guardVariable != null) {
try {
guardVariable.setContainer(null);
} catch (Exception e) {
throw new InternalErrorException(
"Failed to set container of " + guardVariable
+ " to null");
}
}
}
}
/** Set the value of the index-th element.
*
* @param index The index.
* @param value The value.
* @see #getValue(int)
*/
public void setValue(int index, Object value) {
switch (index) {
case 0:
_guardValue = (String) value;
break;
}
}
/** Set the values of all the elements with a string that describes them.
*
* @param values A string that describes the new values of all the
* elements.
* @see #getValues()
*/
public void setValues(String values) {
FieldIterator fieldIterator = new FieldIterator(values);
_guardValue = _decodeStringField(0, fieldIterator);
}
/** Validate the enablements and values of all the elements.
*
* @exception ValidationException If some elements are invalid.
*/
public void validate() throws ValidationException {
if (_guardValue.equals("")) {
throw new ValidationException("guardvalue name must not be empty.");
}
}
/** The elements.
*/
private static final CriterionElement[] _ELEMENTS = { new StringCriterionElement(
"GuardValue", false, false, true) };
/** Value of the guardValue element.
*/
private String _guardValue;
}