Package net.ssehub.easy.varModel.cstEvaluation

Class EvaluationVisitor

    • Constructor Detail

      • EvaluationVisitor

        public EvaluationVisitor()
        Creates an evaluation visitor.

      • EvaluationVisitor

        public EvaluationVisitor​(IConfiguration config,
                         IAssignmentState assignmentState,
                         boolean assignmentsOnly,
                         IValueChangeListener listener)
        Creates an evaluation visitor.
        Parameters:
        config - the configuration to take already evaluated values from
        assignmentState - the state for the assignments (may be null if no assignment shall take place)
        assignmentsOnly - if true process only assignments, else process all constraints
        listener - a listener to notify some external mechanism about a changed variable (may be null)

    • Method Detail

      • init

        public void init​(IConfiguration config,
                 IAssignmentState assignmentState,
                 boolean assignmentsOnly,
                 IValueChangeListener listener)
        Clears the visitor for reuse.
        Parameters:
        config - the configuration to take already evaluated values from
        assignmentState - the state for the assignments (may be null if no assignment shall take place)
        assignmentsOnly - if true process only assignments, else process all constraints
        listener - a listener to notify some external mechanism about a changed variable (may be null)

      • setResolutionListener

        public void setResolutionListener​(IResolutionListener listener)
        Defines the current (optional) resolution listener.
        Parameters:
        listener - the listener (may be null to indicate that no listener is required)

      • setValueChangeListener

        public void setValueChangeListener​(IValueChangeListener listener)
        Defines the current (optional) value change listener listener.
        Parameters:
        listener - the listener (may be null to indicate that no listener is required)

      • addMapping

        void addMapping​(AbstractVariable decl,
                IDecisionVariable var)
        Adds an explicit mapping of a declaration to a decision variable taking precedence over the configuration. This is in particular required for evaluating freeze-but.
        Parameters:
        decl - the declaration
        var - the variable

      • removeMapping

        void removeMapping​(AbstractVariable decl)
        Removes an explicit mapping of a declaration to a decision variable as counterpart for addMessage(Message). This is in particular required for evaluating freeze-but.
        Parameters:
        decl - the declaration

      • setDispatchScope

        public Project setDispatchScope​(Project scope)
        Defines the top-level search scope for dynamic dispatch of custom operations.
        Parameters:
        scope - the scope (may be null to disable dynamic dispatch)
        Returns:
        the scope before calling this operation

      • setSelfValue

        public void setSelfValue​(CompoundValue selfValue)
        Changes the value of "self" for the current compound in case that constraint evaluation does not happen via visit(ConstraintSyntaxTree). May be overwritten by visit(ConstraintSyntaxTree).
        Parameters:
        selfValue - the self value, may be null if evaluation happens not in a compound

      • clear

        public void clear()
        Clears the visitor for reuse (including the dispatch scope and the context).
        See Also:
        clearIntermediary()

      • clearIntermediary

        public void clearIntermediary()
        Clears intermediary state information including result, assignment state, messages, warnings, failed and selfVars. Call at least setAssignmentState(IAssignmentState) to reuse this instance.

      • clearResult

        public void clearResult()
        Clears the result. Does not clear the context stack, which may contain frames in case of evaluation problems.

      • getResult

        public Value getResult()
        Description copied from interface: IConstraintEvaluator
        Returns the evaluation result.
        Specified by:
        getResult in interface IConstraintEvaluator
        Returns:
        may be null in case of an expression that cannot be evaluated (shall lead to an exception)

      • getResultVariable

        public IDecisionVariable getResultVariable()
        Returns the result variable.
        Returns:
        may be null in case of an expression that cannot be evaluated (shall lead to an exception)

      • getResultAccessor

        protected EvaluationAccessor getResultAccessor​(boolean nullify)
        Just for internal purposes of derived classes - get the result accessor. If you use this method, you are anyway responsible for cleaning up the result properly.
        Parameters:
        nullify - set result to null and caller takes over full responsibility for releasing, false leave responsibility in this part
        Returns:
        the result accessor

      • setResultAcessor

        protected void setResultAcessor​(EvaluationAccessor result)
        Defines the result accessor and overrides an existing accessor. Please use with care. This part takes over the responsibility for releasing the accessor.
        Parameters:
        result - the new result accessor (may be null for none)

      • constraintFulfilled

        public static boolean constraintFulfilled​(java.lang.Object result)
        Returns whether the result of a constraint evaluation indicates that the evaluated constraint was fulfilled.
        Parameters:
        result - the evaluation result
        Returns:
        true if the constraint is fulfilled, false else

      • constraintFailed

        public static boolean constraintFailed​(java.lang.Object result)
        Returns whether the result of a constraint evaluation indicates that the evaluated constraint failed.
        Parameters:
        result - the evaluation result
        Returns:
        true if the constraint failed, false else

      • constraintUndefined

        public static boolean constraintUndefined​(java.lang.Object result)
        Returns whether the result of a constraint evaluation indicates that (at least one part of) the constraint was undefined.
        Parameters:
        result - the evaluation result
        Returns:
        true if (at least one part of) the constraint was undefined, false else

      • constraintFulfilled

        public boolean constraintFulfilled()
        Description copied from interface: IConstraintEvaluator
        Returns whether the constraint evaluation indicates that the evaluated constraint was fulfilled.
        Specified by:
        constraintFulfilled in interface IConstraintEvaluator
        Returns:
        true if the constraint is fulfilled, false else

      • constraintFailed

        public boolean constraintFailed()
        Description copied from interface: IConstraintEvaluator
        Returns whether the constraint evaluation indicates that the evaluated constraint failed. For instance, the following should fail: 
        
 a = true;
 b = false;
 
 !a or b
        Specified by:
        constraintFailed in interface IConstraintEvaluator
        Returns:
        true if the constraint failed, false else

      • constraintUndefined

        public boolean constraintUndefined()
        Description copied from interface: IConstraintEvaluator
        Returns whether the constraint evaluation indicates that (at least one part of) the constraint was undefined.
        Specified by:
        constraintUndefined in interface IConstraintEvaluator
        Returns:
        true if (at least one part of) the constraint was undefined, false else

      • constraintIsAWarning

        public boolean constraintIsAWarning()
        Description copied from interface: IConstraintEvaluator
        Returns whether the constraint was internally evaluated to false but finally leads to a successful execution and shall lead to a warning to the user.
        Specified by:
        constraintIsAWarning in interface IConstraintEvaluator
        Returns:
        true if the constraint shall be issued as a warning, false else.

      • getFailedExpression

        public ConstraintSyntaxTree[] getFailedExpression()
        Returns the innermost failed expression(s).
        Returns:
        null if there were no failed expressions, the (innermost) failed expressions else (currently at maximum one)

      • addMessage

        private void addMessage​(EvaluationVisitor.Message message)
        Adds a message.
        Parameters:
        message - the message to be added

      • error

        private void error​(java.lang.String text,
                   int code)
        Adds an error message.
        Parameters:
        text - the text of the error message
        code - the message code

      • notImplementedError

        private void notImplementedError​(java.lang.String subject)
        Adds a not implemented error message.
        Parameters:
        subject - the subject that is not implemented

      • exception

        private void exception​(java.lang.Throwable th)
        Adds a throwable as error message.
        Parameters:
        th - the throwable

      • visit

        public ConstraintSyntaxTree visit​(ConstraintSyntaxTree cst)
        Visits a constraint syntax tree. This method considers partial expressions with static access and wraps the entire expression into an all-quantified constraint. "Free" variables are bound by all-quantors constructed for individual compound types. Multiple slots for one compound are then bound by variable let expressions. As a result, the entire constraint is bound against the all-instance sets of the individual types and can be handled as all other constraints by the EvaluationVisitor.
        Parameters:
        cst - the constraint to be evaluated
        Returns:
        the rewritten constraint if needed, cst else

      • bindFreeVarsByQuantors

        private ConstraintSyntaxTree bindFreeVarsByQuantors​(ConstraintSyntaxTree cst,
                                                    java.util.Map<IDatatype,​java.util.List<AbstractVariable>> quantorGroups)
        Binds the free variables by one quantor per quantor group.
        Parameters:
        cst - the constraint to be quantorized/bound
        quantorGroups - the quantor groups as determined by #groupQuantors(Iterator)
        Returns:
        the resulting rewritten constraint (may be null if errors occcurred)

      • evaluateCustomOperation

        private void evaluateCustomOperation​(CustomOperation operation,
                                     EvaluationAccessor operand,
                                     EvaluationAccessor[] args)
        Evaluates the given custom operation.
        Parameters:
        operation - the operation to be evaluated
        operand - the call operand (may be null; if not, added to parameters)
        args - the call arguments

      • getAccessor

        private EvaluationAccessor getAccessor​(EvaluationAccessor accessor,
                                       ConstraintSyntaxTree expression)
        Returns an evaluation accessor for expression if accessor is not already determined.
        Parameters:
        accessor - the accessor
        expression - the expression
        Returns:
        the accessor, may be accessor, may be a new accessor, may be null. Must be released if not null

      • evaluateOclFeatureCall

        private boolean evaluateOclFeatureCall​(OCLFeatureCall call)
        Returns whether an OCL feature call shall be evaluated.
        Parameters:
        call - the specific call to consider
        Returns:
        true if the call shall be evaluated, false else

      • setAllowPropagation

        private boolean setAllowPropagation​(Operation op,
                                    boolean allow)
        Encapsulates a null context (some of the model test cases).
        Parameters:
        op - the operation to consider
        allow - the new state of the allow flag
        Returns:
        the old state of the allow flag

      • containsIsDefined

        private boolean containsIsDefined​(ConstraintSyntaxTree constraint)
        Returns whether constraint somewhere contains/calls an isDefined operation. Alternative would be constraint rewriting during parsing.
        Parameters:
        constraint - the constraint
        Returns:
        true if isDefined is somewhere used, false else

      • evaluateArguments

        private boolean evaluateArguments​(OCLFeatureCall call,
                                  Operation op,
                                  EvaluationAccessor operand,
                                  EvaluationAccessor[] args)
        Evaluates the arguments.
        Parameters:
        call - the call
        op - the resolved operation
        operand - the operand
        args - the arguments (empty, size of number of parameters, modified as side effect)
        Returns:
        true for successful, false else

      • recordIfFailed

        private void recordIfFailed​(ConstraintSyntaxTree cst)
        Records a constraint syntax tree if it failed.
        Parameters:
        cst - the syntax tree to record

      • dynamicDispatch

        private CustomOperation dynamicDispatch​(CustomOperation operation,
                                        EvaluationAccessor[] args)
        Performs a dynamic dispatch of operation according to the given actual arguments in args, i.e., this method searches and returns a method that fits better to the actual arguments then the statically bound operation.
        Parameters:
        operation - the operation to be dispatched
        args - the actual arguments
        Returns:
        the best fitting operation

      • disposeLocalVariable

        void disposeLocalVariable​(LocalDecisionVariable var)
        Notifies the resolution listener about disposing a local variable.
        Parameters:
        var - the variable

      • disposeLocalVariables

        void disposeLocalVariables​(LocalDecisionVariable[] vars)
        Notifies the resolution listener about disposing several local variables.
        Parameters:
        vars - the variables

      • addLocalVariable

        private LocalDecisionVariable addLocalVariable​(LocalConfiguration cfg,
                                               DecisionVariableDeclaration decl,
                                               ConstraintSyntaxTree initEx,
                                               boolean notify)
        Adds a new local decision variable based on decl to cfg.
        Parameters:
        cfg - the local configuration to add the new variable
        decl - the variable declaration
        initEx - the explicitly given initialization expression, may be null then this method considers the default value of decl
        notify - notify the resolution listener about the creation of the new variable, unregistering must follow
        Returns:
        the created local variable

      • executeContainerIteration

        private boolean executeContainerIteration​(ContainerOperationCall call,
                                          LocalDecisionVariable[] declarators,
                                          int iterCount,
                                          VariableAccessor resultVar,
                                          IIteratorEvaluator evaluator)
        Executes the container iteration.
        Parameters:
        call - the container operation call to be executed
        declarators - all declarators of the call in terms of decision variables
        iterCount - the number of iterators within the declarators
        resultVar - the result variable to be modified as a side effect during the iteration (result aggregation)
        evaluator - the evaluator corresponding to call (may be null in case of an apply operation)
        Returns:
        true if successful, false if unevaluated

      • containerException

        private boolean containerException​(java.lang.Throwable throwable)
        Just a wrapper for container exceptions constantly returning false. Calls exception(Throwable).
        Parameters:
        throwable - the exception
        Returns:
        false

      • isFreezeVariable

        private boolean isFreezeVariable​(ConstraintSyntaxTree cst)
        Returns whether cst is a freeze variable.
        Parameters:
        cst - the cst to check
        Returns:
        true if cst contains a freeze variable, false else

      • getOperationEvaluator

        protected IOperationEvaluator getOperationEvaluator​(Operation operation)
        Returns the operation evaluator for the given operation. This method is intended to be overridden in case that other operations than the default ones from the EvaluatorRegistry shall be used.
        Parameters:
        operation - the operation to return the evaluator for
        Returns:
        the operation evaluator (or null if none is known)

      • getIteratorEvaluator

        protected IIteratorEvaluator getIteratorEvaluator​(Operation operation)
        Returns the iterator evaluator for the given operation. This method is intended to be overridden in case that other operations than the default ones from the EvaluatorRegistry shall be used.
        Parameters:
        operation - the operation to return the evaluator for
        Returns:
        the iterator evaluator (or null if none is known)

      • getTargetState

        protected IAssignmentState getTargetState​(IDecisionVariable var)
        Returns the target state for a variable which is actually being assigned. This method is intended to be overriden if state conflicts shall be checked before assignment.
        Parameters:
        var - variable
        Returns:
        the target state for the variable, may be null if assignment is not permitted

      • getTargetState

        protected IAssignmentState getTargetState()
        Returns the target assignment state assigned to this visitor.
        Returns:
        the target state