text: /*
   * Copyright (c) 2011-2017, The DART development contributors
   * All rights reserved.
   *
   * The list of contributors can be found at:
   *   https://github.com/dartsim/dart/blob/master/LICENSE
   *
   * This file is provided under the following "BSD-style" License:
   *   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 following disclaimer.
   *   * Redistributions in binary form must reproduce the above
   *     copyright notice, this list of conditions and the following
   *     disclaimer in the documentation and/or other materials provided
   *     with the distribution.
   *   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 THE COPYRIGHT HOLDER 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 "dart/common/Subject.hpp"
  #include "dart/common/Observer.hpp"
  
  namespace dart {
  namespace common {
  
  //==============================================================================
  Observer::~Observer()
  {
    std::set<const Subject*>::iterator it = mSubjects.begin(),
                                            end = mSubjects.end();
    while( it != end )
      (*(it++))->removeObserver(this);
    // We do this tricky iterator method to deal with the fact that mObservers
    // will be changing as we go through the loop
  }
  
  //==============================================================================
  void Observer::receiveDestructionNotification(const Subject* _subject)
  {
    removeSubject(_subject);
    handleDestructionNotification(_subject);
  }
  
  //==============================================================================
  void Observer::handleDestructionNotification(const Subject*)
  {
    // Do nothing
  }
  
  //==============================================================================
  void Observer::addSubject(const Subject* _subject)
  {
    if(nullptr == _subject)
      return;
  
    if(mSubjects.find(_subject) != mSubjects.end())
      return;
  
    mSubjects.insert(_subject);
    _subject->addObserver(this);
  }
  
  //==============================================================================
  void Observer::removeSubject(const Subject* _subject)
  {
    if(nullptr == _subject)
      return;
  
    if(mSubjects.find(_subject) == mSubjects.end())
      return;
  
    mSubjects.erase(_subject);
    _subject->removeObserver(this);
  }
  
  //==============================================================================
  void Observer::removeAllSubjects()
  {
    std::set<const Subject*>::iterator it = mSubjects.begin(),
                                            end = mSubjects.end();
  
    while(it != end)
      removeSubject(*(it++));
  }
  
  } // namespace common
  } // namespace dart
  