source: src/CodePatterns/Observer/GlobalObservableInfo.hpp@ c1e104

/*
 * GlobalObservableInfo.hpp
 *
 *  Created on: Jul 4, 2015
 *      Author: heber
 */

#ifndef GLOBALOBSERVABLEINFO_HPP_
#define GLOBALOBSERVABLEINFO_HPP_

// include config.h
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <map>
#include <set>

#include "CodePatterns/Range.hpp"
#include "CodePatterns/Singleton.hpp"

#include <boost/thread/recursive_mutex.hpp>

class Channels;
class Observable;
class Observer;
class Notification;

/** This class contains all global maps storing information about observers
 * and which is signed on to which Observable.
 *
 * All infrastructure for the observer-pattern is bundled at a central place
 * this is more efficient if many objects can be observed (inherit from observable)
 * but only few are actually coupled with observers. E.g. TMV has over 500.000 Atoms,
 * which might become observable. Handling Observable infrastructure in each of
 * these would use memory for each atom. By handling Observer-infrastructure
 * here we only need memory for objects that actually are observed.
 * See [Gamma et al, 1995] p. 297
 *
 * We have transfered this information into a single singleton as we need to
 * control the time when the information is destroyed. Objects in here must
 * remain valid and accessible till the very last Observable in some other
 * module (i.e. not in this library) is destroyed.
 */
class GlobalObservableInfo : public Singleton<GlobalObservableInfo>
{
  //!> singleton pattern is friend to access private cstor
  friend class Singleton<GlobalObservableInfo>;

private:
  /** Private cstor for GlobalObservableInfo.
   *
   * Must be private as is singleton.
   *
   */
  GlobalObservableInfo();

  /** Dstor for GlobalObservableInfo.
   *
   */
  ~GlobalObservableInfo();

public:
  /** This class is only used to distinguish from size_t in the overload.
   *
   * It encapsulates a const int (the priority level) and checks valid bounds
   * in constructor.
   *
   */
  class PriorityLevel {
  public:
    /** Constructor of PriorityLevel.
     *
     * \note We check whether the level is within Observable::PriorityLevel::ValidRange.
     *
     * @param i priority level encapsulated in this class.
     */
    explicit PriorityLevel(const int i);
    ~PriorityLevel();

    const int level;
  private:
    friend class GlobalObservableInfo;

    static range<int> ValidRange;
  };

public:
  boost::recursive_mutex& getObservablesMapMutex()
  { return ObservablesMapLock; }

  typedef std::multimap<int,Observer*> callees_t;
  typedef std::set<Notification*> notificationSet;

  std::map<Observable*, int>& getdepth()
  { return depth; }
  typedef std::map<Observable*,callees_t > calltable_t;
  calltable_t& getcallTable()
  { return callTable; }
  std::map<Observable*,std::set<Notification*> >& getnotifications()
  { return notifications; }
  std::set<Observable*>& getbusyObservables()
  { return busyObservables; }

  const range<int>& getValidRange()
  { return PriorityLevel::ValidRange; }

  static const PriorityLevel PriorityDefault;

private:
  std::map<Observable*, int> depth;
  std::map<Observable*,callees_t> callTable;
  std::map<Observable*,notificationSet> notifications;
  std::set<Observable*> busyObservables;

  boost::recursive_mutex ObservablesMapLock; //!< a lock for the pointer of the instance
};


#endif /* GLOBALOBSERVABLEINFO_HPP_ */