/* An actor that outputs the maximum value that it has received since the start
of execution.
Copyright (c) 2008-2014 The Regents of the University of California.
All rights reserved.
Permission is hereby granted, without written agreement and without
license or royalty fees, to use, copy, modify, and distribute this
software and its documentation for any purpose, provided that the above
copyright notice and the following two paragraphs appear in all copies
of this software.
IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY
FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF
THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF
CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
ENHANCEMENTS, OR MODIFICATIONS.
PT_COPYRIGHT_VERSION_2
COPYRIGHTENDKEY
*/
package ptolemy.actor.lib;
import java.util.HashSet;
import java.util.Set;
import ptolemy.data.ScalarToken;
import ptolemy.data.type.BaseType;
import ptolemy.data.type.TypeConstant;
import ptolemy.graph.Inequality;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
import ptolemy.kernel.util.Workspace;
/**
Output the maximum value seen since the start of execution of the model.
On each firing, this actor consumes exactly one scalar token at its input port.
The value of the token is compared to the maximum value maintained since the
start of the execution. The greater of the two is output to the output port in
the same firing, and the maximum value is set with that greater value in
postfire().
@author Thomas Huining Feng
@version $Id: RunningMaximum.java 70398 2014-10-22 23:44:32Z cxh $
@since Ptolemy II 10.0
@Pt.ProposedRating Yellow (tfeng)
@Pt.AcceptedRating Red (tfeng)
*/
public class RunningMaximum extends Transformer {
/** Construct an actor with the specified container and name.
*
* @param container The composite actor to contain this one.
* @param name The name of this actor.
* @exception IllegalActionException If the entity cannot be contained
* by the proposed container.
* @exception NameDuplicationException If the container already has an
* actor with this name.
*/
public RunningMaximum(CompositeEntity container, String name)
throws NameDuplicationException, IllegalActionException {
super(container, name);
}
///////////////////////////////////////////////////////////////////
//// public methods ////
/** Clone this actor into the specified workspace. The new actor is
* not added to the directory of that workspace (you must do this
* yourself if you want it there).
* The result is a new actor with the same ports as the original, but
* no connections and no container. A container must be set before
* much can be done with this actor.
*
* @param workspace The workspace for the cloned object.
* @exception CloneNotSupportedException If cloned ports cannot have
* as their container the cloned entity (this should not occur), or
* if one of the attributes cannot be cloned.
* @return A new ComponentEntity.
*/
@Override
public Object clone(Workspace workspace) throws CloneNotSupportedException {
RunningMaximum newObject = (RunningMaximum) super.clone(workspace);
return newObject;
}
/** Consume a token at the input port, and produce the greater of that value
* and the maintained maximum value to the output port.
*
* @exception IllegalActionException If getting token from input or
* sending token to output throws it.
*/
@Override
public void fire() throws IllegalActionException {
super.fire();
_value = (ScalarToken) input.get(0);
if (_maximum == null || _value.isGreaterThan(_maximum).booleanValue()) {
output.broadcast(_value);
} else {
output.broadcast(_maximum);
}
}
/** Initialize the maintained maximum value to be null so it will be set
* with the first input at the input port.
*
* @exception IllegalActionException If the initialize() method of the
* superclass throws it.
*/
@Override
public void initialize() throws IllegalActionException {
super.initialize();
_maximum = null;
}
/** Commit the maximum value observed since the start of execution to the
* maximum field to be compared with later inputs.
*
* @exception IllegalActionException If the postfire() method of the
* superclass throws it.
*/
@Override
public boolean postfire() throws IllegalActionException {
boolean result = super.postfire();
if (_maximum == null || _value.isGreaterThan(_maximum).booleanValue()) {
_maximum = _value;
}
return result;
}
/** Return true if the prefire() method of the superclass returns true, and
* there is at least one token at the input port.
*
* @exception IllegalActionException If the prefire() method of the
* superclass throws it.
*/
@Override
public boolean prefire() throws IllegalActionException {
return super.prefire() && input.hasToken(0);
}
///////////////////////////////////////////////////////////////////
//// protected methods ////
/** Eliminate default constraints.
* @return null
*/
@Override
protected Set _defaultTypeConstraints() {
return null;
}
/** Set input <= output, input <= Scalar. If backward type inference is
* enabled and input has no declared type, also set input >= output.
* @return A set of inequality constraints.
*/
@Override
protected Set _customTypeConstraints() {
Set result = new HashSet();
/* input <= output */
result.add(new Inequality(input.getTypeTerm(), output.getTypeTerm()));
/* input <= Scalar. */
result.add(new Inequality(input.getTypeTerm(), new TypeConstant(
BaseType.SCALAR)));
/* input >= output if backward type inference is enabled */
if (isBackwardTypeInferenceEnabled()
&& input.getTypeTerm().isSettable()) {
result.add(new Inequality(output.getTypeTerm(), input.getTypeTerm()));
}
return result;
}
///////////////////////////////////////////////////////////////////
//// private variables ////
// The maximum value observed so far.
private ScalarToken _maximum;
// The value observed in the current firing.
private ScalarToken _value;
}