ptolemy.actor.gt
Class Constraint
java.lang.Object
ptolemy.kernel.util.NamedObj
ptolemy.kernel.util.Attribute
ptolemy.kernel.util.AbstractSettableAttribute
ptolemy.data.expr.Variable
ptolemy.data.expr.Parameter
ptolemy.actor.gt.GTParameter
ptolemy.actor.gt.Constraint
- All Implemented Interfaces:
- java.io.Serializable, java.lang.Cloneable, HasTypeConstraints, Typeable, Changeable, Debuggable, DebugListener, Derivable, ModelErrorHandler, MoMLExportable, Moveable, Nameable, Settable, ValueListener
public class Constraint
- extends GTParameter
Constraint used to restrict pattern matching in model transformations. A
constraint contains an expression that must be evaluable into a boolean at the
time the transformation rule is applied. When the expression is specified at
design time, it is parsed and a syntax tree is generated. If the parsing is not
successful, a design time exception occurs. If the parse is successful, the
constraint is evaluated every time a match to the pattern is found. No
exception will be shown at the time of pattern matching even if the constraint
cannot be successfully evaluated. In that case, the constraint will only be
considered false. A constraint is satisfied if and only if it can be
successfully evaluated and the result is boolean true.
- Since:
- Ptolemy II 7.1
- Version:
- $Id: Constraint.java 57040 2010-01-27 20:52:32Z cxh $
- Author:
- Thomas Huining Feng
- See Also:
- Serialized Form
- Accepted Rating:
- Proposed Rating:
| Fields inherited from class ptolemy.kernel.util.NamedObj |
_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _elementName, _isPersistent, _verbose, _workspace, ATTRIBUTES, CLASSNAME, COMPLETE, CONTENTS, DEEP, FULLNAME, LINKS |
|
Constructor Summary |
Constraint(NamedObj container,
java.lang.String name)
Constraint a constraint. |
| Methods inherited from class ptolemy.data.expr.Variable |
_description, _evaluate, _notifyValueListeners, _parseIfNecessary, _propagate, _propagateToValueListeners, _propagateValue, _setToken, _setTokenAndNotify, addValueListener, clone, getDeclaredType, getExpression, getFreeIdentifiers, getParserScope, getScope, getScope, getToken, getType, getTypeTerm, getValueAsString, getVariable, getVisibility, invalidate, isKnown, isLazy, isStringMode, isTypeAcceptable, removeValueListener, reset, setExpression, setLazy, setName, setParseTreeEvaluator, setStringMode, setToken, setToken, setTypeAtLeast, setTypeAtLeast, setTypeAtMost, setTypeEquals, setTypeSameAs, setUnknown, setVisibility, stringRepresentation, toString, typeConstraintList, typeConstraints, validate, valueChanged |
| Methods inherited from class ptolemy.kernel.util.NamedObj |
_addAttribute, _adjustOverride, _attachText, _cloneFixAttributeFields, _debug, _debug, _debug, _debug, _debug, _exportMoMLContents, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _recordDecoratedAttributes, _removeAttribute, _splitName, _stripNumericSuffix, _validateSettables, addChangeListener, addDebugListener, attributeChanged, attributeList, attributeList, attributeTypeChanged, clone, containedObjectsIterator, deepContains, depthInHierarchy, description, description, event, executeChangeRequests, exportMoML, exportMoML, exportMoML, exportMoML, exportMoMLPlain, getAttribute, getAttribute, getAttributes, getChangeListeners, getClassName, getDecoratorAttribute, getDecoratorAttributes, getDerivedLevel, getDerivedList, getDisplayName, getElementName, getFullName, getModelErrorHandler, getName, getName, getPrototypeList, getSource, handleModelError, isDeferringChangeRequests, isOverridden, isPersistent, lazyContainedObjectsIterator, message, propagateExistence, propagateValue, propagateValues, removeChangeListener, removeDebugListener, requestChange, setClassName, setDeferringChangeRequests, setDerivedLevel, setDisplayName, setModelErrorHandler, setPersistent, setSource, sortContainedObjects, toplevel, uniqueName, validateSettables, workspace |
| Methods inherited from class java.lang.Object |
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
editorFactory
public VisibleParameterEditorFactory editorFactory
- The editor factory.
Constraint
public Constraint(NamedObj container,
java.lang.String name)
throws IllegalActionException,
NameDuplicationException
- Constraint a constraint.
- Parameters:
container - The container of the constraint, which is usually the
pattern of a TransformationRule.name - The name of the constraint.
- Throws:
IllegalActionException - If the attribute is not of an
acceptable class for the container, or if the name contains a period.
NameDuplicationException - If the name coincides with
an attribute already in the container.
check
public boolean check(Pattern pattern,
MatchResult matchResult)
- Check whether this constraint is satisfied with the given match in
matchResult to the given pattern. A constraint is satisfied if
and only if it can be successfully evaluated and the result is boolean
true.
- Parameters:
pattern - The pattern.matchResult - The match result.
- Returns:
- true if the constraint is satisfied; false if
it cannot be evaluated or the evaluation result is false.
setContainer
public void setContainer(NamedObj container)
throws IllegalActionException,
NameDuplicationException
- Set the container of this constraint. This method ensures that the
container must be the pattern of a
TransformationRule.
- Overrides:
setContainer in class Variable
- Parameters:
container - The new container, or null if the current
container of this constraint is to be removed.
- Throws:
IllegalActionException - If this attribute is not of the
expected class for the container, or it has no name, or the attribute
and container are not in the same workspace, or the proposed container
would result in recursive containment, or the container is not an
instance of Pattern.
NameDuplicationException - If the container already has
an attribute with the name of this attribute.- See Also:
Attribute.getContainer()
_evaluate
protected void _evaluate(Pattern pattern,
MatchResult matchResult)
throws IllegalActionException
- Evaluate the current expression to a token with the given pattern and
match result using
GTParameter.Evaluator. If
this variable
was last set directly with a token, then do nothing. In other words,
the expression is evaluated only if the value of the token was most
recently given by an expression. The expression is also evaluated
if any of the variables it refers to have changed since the last
evaluation. If the value of this variable
changes due to this evaluation, then notify all
value dependents and notify the container (if there is one) by
calling its attributeChanged() and attributeTypeChanged() methods,
as appropriate. An exception is thrown
if the expression is illegal, for example if a parse error occurs
or if there is a dependency loop.
If evaluation results in a token that is not of the same type
as the current type of the variable, then the type of the variable
is changed, unless the new type is incompatible with statically
specified types (setTypeEquals() and setTypeAtMost()).
If the type is changed, the attributeTypeChanged() method of
the container is called. The container can reject the change
by throwing an exception.
This method may trigger a model error, which is delegated up
the container hierarchy until an error handler is found, and
is ignored if no error handler is found. A model error occurs
if the expression cannot be parsed or cannot be evaluated.
Part of this method is read-synchronized on the workspace.
- Overrides:
_evaluate in class GTParameter
- Parameters:
pattern - The pattern.matchResult - The match result for the match between the pattern
and a host model.
- Throws:
IllegalActionException - If the expression cannot
be parsed or cannot be evaluated, or if a dependency loop is found.