/* A queue that outputs the next token to an output channel that is ready to
receive it.
Copyright (c) 2008-2009 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.domains.de.lib;
import java.util.Arrays;
import ptolemy.actor.util.FIFOQueue;
import ptolemy.data.IntToken;
import ptolemy.data.Token;
import ptolemy.kernel.CompositeEntity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
import ptolemy.kernel.util.Settable;
//////////////////////////////////////////////////////////////////////////
//// SharedQueue
/**
A queue that outputs the next token to an output channel that is ready to
receive it. It can have multiple output channels, and the same number of
trigger channels. Initially all output channels are assumed to be ready. When a
token is available, it is sent to the first channel that is ready, and that
channel is marked not ready. When all channels are not ready, the token would
be queued. If the number of tokens already in the queue is equal to the queue
capacity (0 means infinity), then new tokens are lost.
<p>
To make an output channel ready after a token is sent to it, a triggering
signal needs to be received in the corresponding channel of the trigger port.
@author Thomas Huining Feng
@version $Id$
@since Ptolemy II 7.1
@Pt.ProposedRating Red (tfeng)
@Pt.AcceptedRating Red (tfeng)
*/
public class SharedQueue extends Queue {
/** Construct an actor with the given container and name.
* @param container The container.
* @param name The name of this actor.
* @exception IllegalActionException If the actor cannot be contained
* by the proposed container.
* @exception NameDuplicationException If the container already has an
* actor with this name.
*/
public SharedQueue(CompositeEntity container, String name)
throws NameDuplicationException, IllegalActionException {
super(container, name);
output.setMultiport(true);
persistentTrigger.setVisibility(Settable.NONE);
}
/** If there is an input at the input port, consume it. If there are tokens
* in the queue and there are ready output channels, the tokens are sent to
* those output channels. If triggers are available at the trigger port,
* consume them and make the corresponding output channels ready. Also send
* tokens to those channels if there are tokens available.
* @exception IllegalActionException If getting tokens from input and
* trigger ports or sending token to output throws it.
*/
public void fire() throws IllegalActionException {
if (_debugging) {
_debug("Called fire()");
}
int sizeOutput = _queue.size();
_removeTokens = 0;
for (int i = 0, j = 0; i < trigger.getWidth(); i++) {
if (trigger.hasToken(i)) {
trigger.get(i);
if (sizeOutput > 0) {
_outputReady[i] = false;
output.send(i, (Token) _queue.get(j++));
sizeOutput--;
_removeTokens++;
} else {
_outputReady[i] = true;
}
}
}
if (input.hasToken(0)) {
_token = input.get(0);
for (int i = 0; i < _outputReady.length; i++) {
if (_outputReady[i]) {
_outputReady[i] = false;
output.send(i, _token);
_token = null;
break;
}
}
if (_token != null
&& (_queue.getCapacity() == FIFOQueue.INFINITE_CAPACITY || _queue
.getCapacity() > _queue.size() - _removeTokens)) {
sizeOutput++;
} else {
_token = null;
}
}
size.send(0, new IntToken(sizeOutput));
}
/** Return true if either there is input at the input port, or there are
* triggering signals at the trigger port. Return false otherwise.
*
* @return True if this actor is ready to fire.
* @exception IllegalActionException If the ports cannot be tested for
* availability of tokens.
*/
public boolean prefire() throws IllegalActionException {
if (input.isOutsideConnected() && input.hasToken(0)) {
return true;
}
for (int i = 0; i < trigger.getWidth(); i++) {
if (trigger.hasToken(i)) {
return true;
}
}
return false;
}
/** Make all output channels ready.
*
* @exception IllegalActionException If thrown by the superclass.
*/
public void preinitialize() throws IllegalActionException {
super.preinitialize();
_outputReady = new boolean[output.getWidth()];
Arrays.fill(_outputReady, true);
}
/** Clear the buffer.
*
* @exception IllegalActionException If thrown by the superclass.
*/
public void wrapup() throws IllegalActionException {
super.wrapup();
_outputReady = null;
}
// Each entry represents the readiness of an output channel.
private boolean[] _outputReady;
}