/* An instance of FunctionDependencyOfAtomicActor describes the function
dependency between the inputs and outputs of an atomic actor.
Copyright (c) 2003-2006 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.util;
import ptolemy.actor.AtomicActor;
import ptolemy.actor.IOPort;
import ptolemy.graph.DirectedGraph;
import ptolemy.graph.Edge;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
//////////////////////////////////////////////////////////////////////////
//// FunctionDependencyOfAtomicActor
/**
An instance of this class describes the dependency that data at an output port
has on data at an input port in a firing of the container (an atomic actor).
In particular, an output port does not depend on an input port if the fire() method
of the container produces outputs on the output port or asserts that no outputs
will be produced on the output port in this iteration
without knowing anything about the input port (what data are there,
or even whether there are data). An actor that has one or more output ports that does
not depend on one or more input ports is said to be non-strict.
<p>
By default, each output port of an atomic actor depends on all input
ports of the actor. To change this, an actor should
override the pruneDependencies() method of
AtomicActor to remove dependencies between these ports.
For example, {@link ptolemy.domains.de.lib.TimedDelay}
declares that its <i>output</i> port is not dependent of its <i>input</i>
port by defining this method:
<pre>
public void pruneDependencies() {
super.pruneDependencies();
removeDependency(input, output);
}
</pre>
@see FunctionDependency
@see ptolemy.domains.de.lib.TimedDelay
@see ptolemy.actor.AtomicActor#pruneDependencies()
@author Haiyang Zheng
@version $Id: FunctionDependencyOfAtomicActor.java,v 1.2 2004/02/21
07:57:24 hyzheng Exp $
@since Ptolemy II 4.0
@Pt.ProposedRating Green (hyzheng)
@Pt.AcceptedRating Green (eal)
*/
public class FunctionDependencyOfAtomicActor extends FunctionDependency {
/** Construct a FunctionDependencyOfAtomicActor in the given actor.
* The name of this attribute is always "_functionDependency".
* @param atomicActor The atomic actor.
* @exception IllegalActionException If the name has a period in it, or
* the attribute is not compatible with the specified container.
* @exception NameDuplicationException If the container already contains
* an entity with the specified name.
*/
public FunctionDependencyOfAtomicActor(AtomicActor atomicActor)
throws IllegalActionException, NameDuplicationException {
super(atomicActor);
}
///////////////////////////////////////////////////////////////////
//// public methods ////
/** Remove the dependency that the specified output port has,
* by default, on the specified input port. By default, each
* output port is assumed to have a dependency on all input
* ports. This method is called by the removeDependency() method
* of AtomicActor, which in turn is called by actors in
* their pruneDependencies() method.
* @param inputPort The input port.
* @param outputPort The output port that does not depend on the
* input port.
* @see ptolemy.actor.AtomicActor#removeDependency(IOPort, IOPort)
* @see ptolemy.actor.AtomicActor#pruneDependencies()
*/
public void removeDependency(IOPort inputPort, IOPort outputPort) {
// We do not need the validity checking because this method is
// only called from the _constructDependencyGraph() method, which
// again can only be accessed from the _validate() method.
// The _validate() method does the validity checking already
// and gets the read access of workspace.
DirectedGraph dependencyGraph = _dependencyGraph;
// Note we can not use iterator here because the edges() method
// returns an unmodifiableList. The removeEdge() method will cause
// a concurrentModification exception.
Object[] edges = dependencyGraph.edges().toArray();
for (int i = 0; i < edges.length; i++) {
Edge edge = (Edge) edges[i];
if (edge.source().getWeight().equals(inputPort)
&& edge.sink().getWeight().equals(outputPort)) {
dependencyGraph.removeEdge(edge);
}
}
}
///////////////////////////////////////////////////////////////////
//// protected methods ////
/** Construct a dependency graph. This method first constructs
* the default dependency graph, which asserts that each output
* depends on all inputs, and then calls the
* {@link ptolemy.actor.AtomicActor#pruneDependencies()} method.
*/
protected void _constructDependencyGraph() {
super._constructDependencyGraph();
((AtomicActor) getContainer()).pruneDependencies();
}
}