/* A logical equals operator.
Copyright (c) 1997-2005 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
CALIFORNIA HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES,
ENHANCEMENTS, OR MODIFICATIONS.
PT_COPYRIGHT_VERSION_2
COPYRIGHTENDKEY
*/
package ptolemy.actor.lib.logic;
import ptolemy.actor.lib.Transformer;
import ptolemy.data.BooleanToken;
import ptolemy.data.Token;
import ptolemy.data.type.BaseType;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
//////////////////////////////////////////////////////////////////////////
//// Equals
/**
A logical equals operator. This operator has one input
multiport and one output port that is not a multiport. It will consume
at most one token from each input channel, and compare the tokens
using the isEqualTo() method of the Token class. If all observed
input tokens are equal, then the output will be a true-valued boolean
token. If there is not at least one token on the input channels,
then no output is produced.
The type of the input port is undeclared and will be resolved by the type
resolution mechanism. Note that all input channels must resolve to the
same type. The type of the output port is boolean.
@see Token#isEqualTo(Token)
@author John Li and Edward A. Lee
@version $Id$
@since Ptolemy II 0.4
@Pt.ProposedRating Green (eal)
@Pt.AcceptedRating Green (johnli)
*/
public class Equals extends Transformer {
/** Construct an actor in the specified container with the specified
* name.
* @param container The container.
* @param name The name of this actor within the container.
* @exception IllegalActionException If the actor cannot be contained
* by the proposed container.
* @exception NameDuplicationException If the name coincides with
* an actor already in the container.
*/
public Equals(CompositeEntity container, String name)
throws IllegalActionException, NameDuplicationException {
super(container, name);
input.setMultiport(true);
output.setTypeEquals(BaseType.BOOLEAN);
_attachText("_iconDescription", "<svg>\n"
+ "<rect x=\"-30\" y=\"-15\" " + "width=\"60\" height=\"30\" "
+ "style=\"fill:white\"/>\n" + "<text x=\"-14\" y=\"8\""
+ "style=\"font-size:24\">==</text>\n" + "</svg>\n");
}
///////////////////////////////////////////////////////////////////
//// public methods ////
/** Consume at most one token from each input channel, and output
* the result of comparing these tokens using the isEqualTo() method
* of the Token class. If the input has width 1, then the output
* is always true. If the input has width 0, or there are no
* no input tokens available, then no output is produced.
* @exception IllegalActionException If there is no director.
*/
public void fire() throws IllegalActionException {
super.fire();
BooleanToken result = BooleanToken.TRUE;
Token reference = null;
boolean foundOne = false;
for (int i = 0; i < input.getWidth(); i++) {
if (!input.hasToken(i)) {
continue;
}
foundOne = true;
Token next = input.get(i);
if (reference == null) {
reference = next;
} else if (!(next.isEqualTo(reference)).booleanValue()) {
result = BooleanToken.FALSE;
}
}
if (foundOne) {
output.send(0, result);
}
}
}