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/*****************************************************************************
*
* Copyright (c) 2000 - 2017, Lawrence Livermore National Security, LLC
* Produced at the Lawrence Livermore National Laboratory
* LLNL-CODE-442911
* All rights reserved.
*
* This file is part of VisIt. For details, see https://visit.llnl.gov/. The
* full copyright notice is contained in the file COPYRIGHT located at the root
* of the VisIt distribution or at http://www.llnl.gov/visit/copyright.html.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the disclaimer below.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the disclaimer (as noted below) in the
* documentation and/or other materials provided with the distribution.
* - Neither the name of the LLNS/LLNL nor the names of its contributors may
* be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL LAWRENCE LIVERMORE NATIONAL SECURITY,
* LLC, THE U.S. DEPARTMENT OF ENERGY OR CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*****************************************************************************/
#include <Subject.h>
#include <SimpleObserver.h>
// *******************************************************************
// Method: Subject::Subject
//
// Purpose:
// Constructor for the Subject class.
//
// Programmer: Brad Whitlock
// Creation: Wed Aug 9 16:00:53 PST 2000
//
// Modifications:
//
// *******************************************************************
Subject::Subject()
{
}
// *******************************************************************
// Method: Subject::~Subject
//
// Purpose:
// Destructor for the Subject class.
//
// Programmer: Brad Whitlock
// Creation: Wed Aug 9 16:00:53 PST 2000
//
// Modifications:
// Brad Whitlock, Thu Aug 31 15:17:03 PST 2000
// Added code to tell remaining observers not to try and detach
// from the subject.
//
// *******************************************************************
Subject::~Subject()
{
// If there are still observers around it means that this
// object is being destroyed first. Tell the remaining observers
// that they should not try to detach.
std::vector<SimpleObserver *>::iterator pos;
for(pos = observers.begin(); pos != observers.end(); ++pos)
{
(*pos)->SubjectRemoved(this);
}
}
// *******************************************************************
// Method: Subject::Attach
//
// Purpose:
// Adds an Observer to the list of Observers that are watching the
// Subject. When the subject changes, the new Observer will also
// be called.
//
// Arguments:
// o : A pointer to the new Observer.
//
// Programmer: Brad Whitlock
// Creation: Wed Aug 9 16:02:26 PST 2000
//
// Modifications:
// Cyrus Harrison, Fri Nov 30 09:05:09 PST 2007
// Added guard against adding the same observer multiple times
//
// *******************************************************************
void
Subject::Attach(SimpleObserver *o)
{
// only add the observer if it has not already been attached.
bool has_observer = false;
std::vector<SimpleObserver *>::iterator itr;
for(itr = observers.begin(); itr != observers.end(); ++itr)
{
if(*itr == o)
{
has_observer = true;
break;
}
}
if(!has_observer)
observers.push_back(o);
}
// *******************************************************************
// Method: Subject::Detach
//
// Purpose:
// Removes an Observer from the list of Observers that is maintained
// by the subject. The detached observer will no longer be notified
// when the subject changes.
//
// Arguments:
// o : A pointer to the Observer that will be removed.
//
// Programmer: Brad Whitlock
// Creation: Wed Aug 9 16:03:29 PST 2000
//
// Modifications:
//
// *******************************************************************
void
Subject::Detach(SimpleObserver *o)
{
std::vector<SimpleObserver *>::iterator pos;
// Erase all references to observer o.
for(pos = observers.begin(); pos != observers.end(); )
{
if(*pos == o)
pos = observers.erase(pos);
else
++pos;
}
}
// *******************************************************************
// Method: Subject::Notify
//
// Purpose:
// Notifies all Observers that are watching the subject that the
// subject has changed.
//
// Note:
// If an Observer's update state is false, that Observer is not
// notified of the update because, presumeably, it was the Observer
// that caused the subject to change.
//
// Programmer: Brad Whitlock
// Creation: Wed Aug 9 16:04:43 PST 2000
//
// Modifications:
// Brad Whitlock, Thu Apr 22 16:53:34 PST 2010
// Make a copy of the observers array and work from that. This
// is meant to avoid a rare problem where adding observers to the
// subject being notified can cause undesirable results.
//
// *******************************************************************
void
Subject::Notify()
{
std::vector<SimpleObserver *> obs(observers);
std::vector<SimpleObserver *>::iterator pos;
for(pos = obs.begin(); pos != obs.end(); ++pos)
{
// Update the observer if it wants to be updated. If it didn't
// want to be updated, set its update to true so it will be
// updated next time.
if((*pos)->GetUpdate())
(*pos)->Update(this);
else
(*pos)->SetUpdate(true);
}
}
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