/* A CT actor that detects zero crossings of its trigger input signal.
Copyright (c) 1998-2005 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
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ENHANCEMENTS, OR MODIFICATIONS.
PT_COPYRIGHT_VERSION_2
COPYRIGHTENDKEY
*/
package ptolemy.domains.ct.lib;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
import ptolemy.kernel.util.Settable;
//////////////////////////////////////////////////////////////////////////
//// ZeroCrossingDetector
/**
An event detector that converts continuous signals to discrete events when
the continuous signal crosses zero. This actor is a syntactic sugar
for LevelCrossDetector with level to be 0.0.
@see LevelCrossingDetector
@author Jie Liu
@version $Id$
@since Ptolemy II 0.4
@Pt.ProposedRating Yellow (liuj)
@Pt.AcceptedRating Red (cxh)
*/
public class ZeroCrossingDetector extends LevelCrossingDetector {
/** Construct an actor in the specified container with the specified
* name. The name must be unique within the container or an exception
* is thrown. The container argument must not be null, or a
* NullPointerException will be thrown.
*
* @param container The subsystem that this actor is lived in
* @param name The actor's name
* @exception IllegalActionException If the entity cannot be contained
* by the proposed container.
* @exception NameDuplicationException If name coincides with
* an entity already in the container.
*/
public ZeroCrossingDetector(CompositeEntity container, String name)
throws IllegalActionException, NameDuplicationException {
super(container, name);
// _removeAttribute(level) causes the clone() method to assign null to
// the level attribute, which can cause a NullPointerException when we
// initialize the actor returned by the clone() method.
// (tfeng)
level.setVisibility(Settable.NONE);
_level = 0;
}
}