DataService.h

#ifndef MANTID_KERNEL_DATASERVICE_H_
#define MANTID_KERNEL_DATASERVICE_H_

//----------------------------------------------------------------------
// Includes
//----------------------------------------------------------------------
#ifndef Q_MOC_RUN
#include <boost/shared_ptr.hpp>
#include <boost/algorithm/string.hpp>
#endif
#include <Poco/NotificationCenter.h>
#include <Poco/Notification.h>
#include "MantidKernel/Logger.h"
#include "MantidKernel/Exception.h"
#include "MantidKernel/ConfigService.h"

namespace Mantid {
namespace Kernel {
/** DataService stores instances of a given type.
    This is a templated class, designed to be implemented as a
    singleton. For simplicity and naming conventions, specialized classes must
   be constructed. The specialized
    classes must simply:
    1) call the BaseClass constructor with the Name of the service
    2) Support the SingletonHolder templated class.
    This is the primary data service that  the users will interact with either
   through writing scripts or directly
    through the API. It is implemented as a singleton class.

    Copyright &copy; 2008-2013 ISIS Rutherford Appleton Laboratory, NScD Oak
   Ridge National Laboratory & European Spallation Source

    This file is part of Mantid.

    Mantid is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    Mantid is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.

    File change history is stored at: <https://github.com/mantidproject/mantid>.
    Code Documentation is available at: <http://doxygen.mantidproject.org>
*/
template <typename T> class DLLExport DataService {
private:
  /// Typedef for the map holding the names of and pointers to the data objects
  typedef std::map<std::string, boost::shared_ptr<T>> svcmap;
  /// Iterator for the data store map
  typedef typename svcmap::iterator svc_it;
  /// Const iterator for the data store map
  typedef typename svcmap::const_iterator svc_constit;

public:
  /// Class for named object notifications
  class NamedObjectNotification : public Poco::Notification {
  public:
    NamedObjectNotification(const std::string &name)
        : Poco::Notification(), m_name(name) {}

    /// Returns the name of the object
    std::string objectName() const { return m_name; }

  private:
    std::string m_name; ///< object's name
  };

  /// Base class for DataService notifications that also stores a pointer to the
  /// object
  class DataServiceNotification : public NamedObjectNotification {
  public:
    /// Constructor
    DataServiceNotification(const std::string &name,
                            const boost::shared_ptr<T> obj)
        : NamedObjectNotification(name), m_object(obj) {}
    /// Returns the const pointer to the object concerned or 0 if it is a
    /// general notification
    const boost::shared_ptr<T> object() const { return m_object; }

  private:
    boost::shared_ptr<T> m_object; ///< shared pointer to the object
  };

  /// AddNotification is sent after an new object is added to the data service.
  /// name() and object() return name and pointer to the new object.
  class AddNotification : public DataServiceNotification {
  public:
    AddNotification(const std::string &name, const boost::shared_ptr<T> obj)
        : DataServiceNotification(name, obj) {} ///< Constructor
  };

  /// BeforeReplaceNotification is sent before an object is replaced in the
  /// addOrReplace() function.
  class BeforeReplaceNotification : public DataServiceNotification {
  public:
    /** Constructor.

        @param name :: The name of the replaced object
        @param obj ::  The pointer to the old object
        @param newObj :: The pointer to the new object

        Both old and new objects are guaranteed to exist when an observer
       receives the notification.
    */
    BeforeReplaceNotification(const std::string &name,
                              const boost::shared_ptr<T> obj,
                              const boost::shared_ptr<T> newObj)
        : DataServiceNotification(name, obj), m_newObject(newObj) {}
    const boost::shared_ptr<T> newObject() const {
      return m_newObject;
    } ///< Returns the pointer to the new object.
  private:
    boost::shared_ptr<T> m_newObject; ///< shared pointer to the object
  };

  /// AfterReplaceNotification is sent after an object is replaced in the
  /// addOrReplace() function.
  class AfterReplaceNotification : public DataServiceNotification {
  public:
    /** Constructor.
      * @param name :: The name of the replaced object
      *  @param newObj :: The pointer to the new object
      *  Only new objects are guaranteed to exist when an observer receives the
     * notification.
    */
    AfterReplaceNotification(const std::string &name,
                             const boost::shared_ptr<T> newObj)
        : DataServiceNotification(name, newObj) {}
  };

  /// PreDeleteNotification is sent before an object is deleted from the data
  /// service.
  /// name() and object() return name and pointer to the object being deleted.
  /// The object still exists when the notification is received by an observer.
  class PreDeleteNotification : public DataServiceNotification {
  public:
    /// Constructor
    PreDeleteNotification(const std::string &name,
                          const boost::shared_ptr<T> obj)
        : DataServiceNotification(name, obj) {}
  };

  /// PostDeleteNotification is sent after an object is deleted from the data
  /// service.
  /// name() returns the name of the object being deleted.
  /// The object no longer exists when the notification is received by an
  /// observer.
  class PostDeleteNotification : public NamedObjectNotification {
  public:
    /// Constructor
    PostDeleteNotification(const std::string &name)
        : NamedObjectNotification(name) {}
  };

  /// Clear notification is sent when the service is cleared
  class ClearNotification : public NamedObjectNotification {
  public:
    /// Constructor
    ClearNotification() : NamedObjectNotification("") {}
  };
  /// Rename notification is sent when the rename method is called
  class RenameNotification : public NamedObjectNotification {
  public:
    /// Constructor
    RenameNotification(const std::string &name, const std::string &newName)
        : NamedObjectNotification(name), m_newName(newName) {}

    /// New name for the object
    const std::string &newObjectName() const { return m_newName; }

  private:
    std::string m_newName; ///< New object name
  };

  //--------------------------------------------------------------------------
  /** Add an object to the service
   * @param name :: name of the object
   * @param Tobject :: shared pointer to object to add
   * @throw std::runtime_error if name is empty
   * @throw std::runtime_error if name exists in the map
   * @throw std::runtime_error if a null pointer is passed for the object
   */
  virtual void add(const std::string &name,
                   const boost::shared_ptr<T> &Tobject) {
    checkForEmptyName(name);
    checkForNullPointer(Tobject);

    // Make DataService access thread-safe
    m_mutex.lock();

    // At the moment, you can't overwrite an object (i.e. pass in a name
    // that's already in the map with a pointer to a different object).
    // Also, there's nothing to stop the same object from being added
    // more than once with different names.
    if (!datamap.insert(typename svcmap::value_type(name, Tobject)).second) {
      std::string error =
          " add : Unable to insert Data Object : '" + name + "'";
      g_log.error(error);
      m_mutex.unlock();
      throw std::runtime_error(error);
    } else {
      g_log.debug() << "Add Data Object " << name << " successful" << std::endl;
      m_mutex.unlock();

      notificationCenter.postNotification(new AddNotification(name, Tobject));
    }
    return;
  }

  //--------------------------------------------------------------------------
  /** Add or replace an object to the service.
   * Does NOT throw if the name was already used.
   *
   * @param name :: name of the object
   * @param Tobject :: shared pointer to object to add
   * @throw std::runtime_error if name is empty
   */
  virtual void addOrReplace(const std::string &name,
                            const boost::shared_ptr<T> &Tobject) {
    checkForNullPointer(Tobject);

    // Make DataService access thread-safe
    m_mutex.lock();

    // find if the Tobject already exists
    std::string foundName;
    svc_it it = findNameWithCaseSearch(name, foundName);
    if (it != datamap.end()) {
      g_log.debug("Data Object '" + foundName +
                  "' replaced in data service.\n");
      m_mutex.unlock();

      notificationCenter.postNotification(
          new BeforeReplaceNotification(name, it->second, Tobject));

      m_mutex.lock();
      datamap[foundName] = Tobject;
      m_mutex.unlock();

      notificationCenter.postNotification(
          new AfterReplaceNotification(name, Tobject));
    } else {
      // Avoid double-locking
      m_mutex.unlock();
      DataService::add(name, Tobject);
    }
    return;
  }

  //--------------------------------------------------------------------------
  /** Remove an object from the service.
   * @param name :: name of the object */
  void remove(const std::string &name) {
    // Make DataService access thread-safe
    m_mutex.lock();

    std::string foundName;
    svc_it it = findNameWithCaseSearch(name, foundName);
    if (it == datamap.end()) {
      g_log.debug(" remove '" + name + "' cannot be found");
      m_mutex.unlock();
      return;
    }
    // The map is shared across threads so the item is erased from the map
    // before
    // unlocking the mutex and is held in a local stack variable.
    // This protects it from being modified by another thread.
    auto data = it->second;
    datamap.erase(it);

    // Do NOT use "it" iterator after this point. Other threads may modify the
    // map
    m_mutex.unlock();
    notificationCenter.postNotification(
        new PreDeleteNotification(foundName, data));
    m_mutex.lock();

    data.reset(); // DataService now has no references to the object
    g_log.information("Data Object '" + foundName +
                      "' deleted from data service.");

    m_mutex.unlock();
    notificationCenter.postNotification(new PostDeleteNotification(foundName));
    return;
  }

  //--------------------------------------------------------------------------
  /** Rename an object within the service.
   * @param oldName :: The old name of the object
   * @param newName :: The new name of the object
   */
  void rename(const std::string &oldName, const std::string &newName) {
    checkForEmptyName(newName);

    // Make DataService access thread-safe
    m_mutex.lock();

    std::string foundName;
    svc_it it = findNameWithCaseSearch(oldName, foundName);
    if (it == datamap.end()) {
      g_log.warning(" rename '" + oldName + "' cannot be found");
      m_mutex.unlock();
      return;
    }

    // delete the object with the old name
    auto object = it->second;
    datamap.erase(it);

    // if there is another object which has newName delete it
    it = datamap.find(newName);
    if (it != datamap.end()) {
      notificationCenter.postNotification(
          new AfterReplaceNotification(newName, object));
      datamap.erase(it);
    }

    // insert the old object with the new name
    if (!datamap.insert(typename svcmap::value_type(newName, object)).second) {
      std::string error =
          " add : Unable to insert Data Object : '" + newName + "'";
      g_log.error(error);
      m_mutex.unlock();
      throw std::runtime_error(error);
    }
    g_log.information("Data Object '" + foundName + "' renamed to '" + newName +
                      "'");

    m_mutex.unlock();
    notificationCenter.postNotification(
        new RenameNotification(oldName, newName));

    return;
  }

  //--------------------------------------------------------------------------
  /// Empty the service
  void clear() {
    // Make DataService access thread-safe
    m_mutex.lock();

    datamap.clear();
    m_mutex.unlock();
    notificationCenter.postNotification(new ClearNotification());
    g_log.debug() << typeid(this).name() << " cleared.\n";
  }

  /// Prepare for shutdown
  virtual void shutdown() {
    clear();
  }

  //--------------------------------------------------------------------------
  /** Get a shared pointer to a stored data object
   * @param name :: name of the object */
  boost::shared_ptr<T> retrieve(const std::string &name) const {
    // Make DataService access thread-safe
    Poco::Mutex::ScopedLock _lock(m_mutex);

    std::string foundName;
    svc_it it = findNameWithCaseSearch(name, foundName);
    if (it != datamap.end()) {
      return it->second;
    } else {
      throw Kernel::Exception::NotFoundError(
          "Unable to find Data Object type with name '" + name +
              "': data service ",
          name);
    }
  }

  /// Check to see if a data object exists in the store
  bool doesExist(const std::string &name) const {
    // Make DataService access thread-safe
    Poco::Mutex::ScopedLock _lock(m_mutex);

    std::string foundName;
    svc_it it = findNameWithCaseSearch(name, foundName);
    if (it != datamap.end())
      return true;
    return false;
  }

  /// Return the number of objects stored by the data service
  size_t size() const {
    Poco::Mutex::ScopedLock _lock(m_mutex);

    if (showingHiddenObjects()) {
      return datamap.size();
    } else {
      size_t count = 0;
      for (svc_constit it = datamap.begin(); it != datamap.end(); ++it) {
        if (!isHiddenDataServiceObject(it->first))
          ++count;
      }
      return count;
    }
  }

  /// Get the names of the data objects stored by the service
  std::set<std::string> getObjectNames() const {
    if (showingHiddenObjects())
      return getObjectNamesInclHidden();

    Poco::Mutex::ScopedLock _lock(m_mutex);

    std::set<std::string> names;
    for (svc_constit it = datamap.begin(); it != datamap.end(); ++it) {
      if (!isHiddenDataServiceObject(it->first)) {
        names.insert(it->first);
      }
    }
    return names;
  }

  /// Get the names of the data objects stored by the service
  std::set<std::string> getObjectNamesInclHidden() const {
    Poco::Mutex::ScopedLock _lock(m_mutex);

    std::set<std::string> names;
    for (svc_constit it = datamap.begin(); it != datamap.end(); ++it) {
      names.insert(it->first);
    }
    return names;
  }

  /// Get a vector of the pointers to the data objects stored by the service
  std::vector<boost::shared_ptr<T>> getObjects() const {
    Poco::Mutex::ScopedLock _lock(m_mutex);

    const bool showingHidden = showingHiddenObjects();
    std::vector<boost::shared_ptr<T>> objects;
    objects.reserve(datamap.size());
    for (auto it = datamap.begin(); it != datamap.end(); ++it) {
      if (showingHidden || !isHiddenDataServiceObject(it->first)) {
        objects.push_back(it->second);
      }
    }
    return objects;
  }

  inline static std::string prefixToHide() { return "__"; }

  inline static bool isHiddenDataServiceObject(const std::string &name) {
    return boost::starts_with(name, prefixToHide());
  }

  static bool showingHiddenObjects() {
    int showingHiddenFlag;
    const int success = ConfigService::Instance().getValue(
        "MantidOptions.InvisibleWorkspaces", showingHiddenFlag);
    if (success == 1 && showingHiddenFlag == 1) {
      return true;
    } else {
      return false;
    }
  }

  /// Sends notifications to observers. Observers can subscribe to
  /// notificationCenter
  /// using Poco::NotificationCenter::addObserver(...)
  ///@return nothing
  Poco::NotificationCenter notificationCenter;

protected:
  /// Protected constructor (singleton)
  DataService(const std::string &name) : svcName(name), g_log(svcName) {}
  virtual ~DataService() {}

private:
  /// Private, unimplemented copy constructor
  DataService(const DataService &);
  /// Private, unimplemented copy assignment operator
  DataService &operator=(const DataService &);

  void checkForEmptyName(const std::string &name) {
    if (name.empty()) {
      const std::string error = "Add Data Object with empty name";
      g_log.debug() << error << std::endl;
      throw std::runtime_error(error);
    }
  }

  void checkForNullPointer(const boost::shared_ptr<T> &Tobject) {
    if (!Tobject) {
      const std::string error = "Attempt to add empty shared pointer";
      g_log.debug() << error << std::endl;
      throw std::runtime_error(error);
    }
  }

  /**
   * Find a name in the map and return an iterator pointing to it. This takes
   * the string and if it does not find it then it looks for a match
   * disregarding
   * the case (const version)
   * @param name The string name to search for
   * @param foundName [Output] Stores the name here if one was found. It will be
   * empty if not
   * @returns An iterator pointing at the element or the end iterator
   */
  svc_it findNameWithCaseSearch(const std::string &name,
                                std::string &foundName) const {
    const svcmap &constdata = datamap;
    svcmap &data = const_cast<svcmap &>(constdata);
    if (name.empty())
      return data.end();

    // Exact match
    foundName = name;
    svc_it match = data.find(name);
    if (match != data.end())
      return match;

    // Try UPPER case
    std::transform(foundName.begin(), foundName.end(), foundName.begin(),
                   toupper);
    match = data.find(foundName);
    if (match != data.end())
      return match;

    // Try lower case
    std::transform(foundName.begin(), foundName.end(), foundName.begin(),
                   tolower);
    match = data.find(foundName);
    if (match != data.end())
      return match;

    // Try Sentence case
    foundName = name;
    // Upper cases the first letter
    std::transform(foundName.begin(), foundName.begin() + 1, foundName.begin(),
                   toupper);
    match = data.find(foundName);
    if (match == data.end())
      foundName = "";
    return match;
  }

  /// DataService name. This is set only at construction. DataService name
  /// should be provided when construction of derived classes
  const std::string svcName;
  /// Map of objects in the data service
  svcmap datamap;
  /// Recursive mutex to avoid simultaneous access or notifications
  mutable Poco::Mutex m_mutex;
  /// Logger for this DataService
  Logger g_log;
}; // End Class Data service

} // Namespace Kernel
} // Namespace Mantid

#endif /*MANTID_KERNEL_DATASERVICE_H_*/