/* A port that mirrors the properties of an associated port.

 Copyright (c) 2003-2014 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.hoc;

import ptolemy.actor.TypedIOPort;
import ptolemy.kernel.ComponentEntity;
import ptolemy.kernel.Entity;
import ptolemy.kernel.util.IllegalActionException;
import ptolemy.kernel.util.NameDuplicationException;
import ptolemy.kernel.util.Workspace;
import ptolemy.moml.MoMLChangeRequest;

///////////////////////////////////////////////////////////////////
//// MirrorPort

/**
 This port mirrors the properties of an associated port. That is,
 if either this port or the associated port is changed by
 setInput(), setOutput(), setMultiport(), or if it is removed
 by setContainer(null), or its name is changed by setName(),
 then the mirror port gets the same
 changes.  The changes are also applied to derived ports
 (ports that mirror this one because of the class mechanism).
 <p>
 Users of this class must override their clone(Workspace)
 method to re-establish appropriate port associations in
 the clone.  Cloning this port results in a clone with
 no associations.

 @author Edward A. Lee
 @version $Id$
 @since Ptolemy II 4.0
 @Pt.ProposedRating Yellow (eal)
 @Pt.AcceptedRating Red (neuendor)
 */
public class MirrorPort extends TypedIOPort {
    /** Construct a port in the specified workspace with an empty
     *  string as a name. You can then change the name with setName().
     *  If the workspace argument
     *  is null, then use the default workspace.
     *  The object is added to the workspace directory.
     *  Increment the version number of the workspace.
     *  @param workspace The workspace that will list the port.
     * @exception IllegalActionException If port parameters cannot be initialized.
     */
    public MirrorPort(Workspace workspace) throws IllegalActionException {
        // This constructor is needed for Shallow codgen.
        super(workspace);
    }

    /** Create a new instance of a port.
     *  @param container The container for the port.
     *  @param name The name of the port.
     *  @exception IllegalActionException If the container does not
     *   implement TypedActor.
     *  @exception NameDuplicationException If the name matches that
     *   of a port already in the container.
     */
    public MirrorPort(ComponentEntity container, String name)
            throws IllegalActionException, NameDuplicationException {
        super(container, name);
    }

    ///////////////////////////////////////////////////////////////////
    ////                         public methods                    ////

    /** Clone the object into the specified workspace. This overrides
     *  the base class to unset the associated port. Users of this
     *  class are responsible for resetting it in their clone methods.
     *  @param workspace The workspace for the new object.
     *  @return A new NamedObj.
     *  @exception CloneNotSupportedException If any of the attributes
     *   cannot be cloned.
     *  @see #exportMoML(java.io.Writer, int, String)
     */
    @Override
    public Object clone(Workspace workspace) throws CloneNotSupportedException {
        MirrorPort result = (MirrorPort) super.clone(workspace);
        result._associatedPort = null;
        result._settingAssociatedPort = false;
        return result;
    }

    /** Return the associated port, or null if there is none.
     *  @return The associated port, or null if there is none.
     *  @see #setAssociatedPort(MirrorPort)
     */
    public MirrorPort getAssociatedPort() {
        return _associatedPort;
    }

    /** Specify an associated port.  Once this is specified,
     *  then any changes made to this port (its name, whether it
     *  is an input or output, and whether it is a multiport) are
     *  mirrored in the associated port, and any changes made in
     *  the associated port are mirrored here.
     *  @param port The associated port.
     *  @see #getAssociatedPort()
     */
    public void setAssociatedPort(MirrorPort port) {
        _associatedPort = port;
        port._associatedPort = this;

        // NOTE: The association is not propagated to derived
        // objects because we explicitly propagate all the changes.
    }

    /** Override the base class so that if the container is being
     *  set to null, then the associated port is also deleted
     *  (via a change request).  Note that if the container
     *  of this port is changed to something other than null,
     *  there is no reasonable basis for changing the container
     *  of the associated port, so it is left unchanged.
     *  @param container The proposed container.
     *  @exception IllegalActionException If the proposed container is not a
     *   ComponentEntity, doesn't implement Actor, or has no name,
     *   or the port and container are not in the same workspace. Or
     *   it's not null
     *  @exception NameDuplicationException If the container already has
     *   a port with the name of this port.
     */
    @Override
    public void setContainer(Entity container)
            throws IllegalActionException, NameDuplicationException {
        super.setContainer(container);

        if (container == null && _associatedPort != null
                && _associatedPort.getContainer() != null) {
            // Use a MoML change request to ensure propagation.
            // Note that when that change request is executed,
            // this port will be the associated port, but no
            // change request will be issued because its container
            // is already null.
            MoMLChangeRequest request = new MoMLChangeRequest(this,
                    _associatedPort.getContainer(),
                    "<deletePort name=\"" + _associatedPort.getName() + "\"/>");
            _associatedPort.getContainer().requestChange(request);
        }
    }

    /** Override the base class to also set the associated port,
     *  if there is one.
     *  @param isInput True to make this an input port.
     *  @exception IllegalActionException If changing the port status is
     *   not permitted.
     */
    @Override
    public void setInput(boolean isInput) throws IllegalActionException {
        super.setInput(isInput);

        if (_associatedPort != null && _associatedPort.isInput() != isInput) {
            // Use a MoML change request to ensure propagation.
            // Note that when that change request is executed,
            // this port will be the associated port, but no
            // change request will be issued because it already
            // has matching status.
            String value = isInput ? "true" : "false";
            MoMLChangeRequest request = new MoMLChangeRequest(this,
                    _associatedPort.getContainer(),
                    "<property name=\"input\" value=\"" + value + "\"/>");
            _associatedPort.getContainer().requestChange(request);
        }
    }

    /** Override the base class to also set the associated port,
     *  if there is one.
     *  @param isMultiport True to make this a multiport.
     *  @exception IllegalActionException If changing the port status is
     *   not permitted.
     */
    @Override
    public void setMultiport(boolean isMultiport)
            throws IllegalActionException {
        super.setMultiport(isMultiport);

        if (_associatedPort != null
                && _associatedPort.isMultiport() != isMultiport) {
            // Use a MoML change request to ensure propagation.
            // Note that when that change request is executed,
            // this port will be the associated port, but no
            // change request will be issued because it already
            // has matching status.
            String value = isMultiport ? "true" : "false";
            MoMLChangeRequest request = new MoMLChangeRequest(this,
                    _associatedPort.getContainer(),
                    "<property name=\"multiport\" value=\"" + value + "\"/>");
            _associatedPort.getContainer().requestChange(request);
        }

        // Set the associated port first, so that if it fails, we
        // don't change the status of this one either.
        if (!_settingAssociatedPort && _associatedPort != null) {
            try {
                _settingAssociatedPort = true;
                _associatedPort.setMultiport(isMultiport);
            } finally {
                _settingAssociatedPort = false;
            }
        }

        // Note that propagation is handled by the call below.
        super.setMultiport(isMultiport);
    }

    /** Override the base class to also set the associated port,
     *  if there is one.
     */
    @Override
    public void setName(String name)
            throws IllegalActionException, NameDuplicationException {
        super.setName(name);

        if (_associatedPort != null
                && !_associatedPort.getName().equals(name)) {
            // Use a MoML change request to ensure propagation.
            // Note that when that change request is executed,
            // this port will be the associated port, but no
            // change request will be issued because it already
            // has matching status.
            MoMLChangeRequest request = new MoMLChangeRequest(this,
                    _associatedPort, "<rename name=\"" + name + "\"/>");
            _associatedPort.requestChange(request);
        }
    }

    /** Override the base class to also set the associated port,
     *  if there is one.
     *  @param isOutput True to make this an output port.
     *  @exception IllegalActionException If changing the port status is
     *   not permitted.
     */
    @Override
    public void setOutput(boolean isOutput) throws IllegalActionException {
        super.setOutput(isOutput);

        if (_associatedPort != null && _associatedPort.isOutput() != isOutput) {
            // Use a MoML change request to ensure propagation.
            // Note that when that change request is executed,
            // this port will be the associated port, but no
            // change request will be issued because it already
            // has matching status.
            String value = isOutput ? "true" : "false";
            MoMLChangeRequest request = new MoMLChangeRequest(this,
                    _associatedPort.getContainer(),
                    "<property name=\"output\" value=\"" + value + "\"/>");
            _associatedPort.getContainer().requestChange(request);
        }
    }

    ///////////////////////////////////////////////////////////////////
    ////                         private variables                 ////

    /** The associated port, if there is one. */
    private MirrorPort _associatedPort = null;

    /** Flag indicating that we are setting the associated port. */
    private boolean _settingAssociatedPort = false;
}