ClickHouse/base/poco/Foundation/include/Poco/PriorityStrategy.h

//
// PriorityStrategy.h
//
// Library: Foundation
// Package: Events
// Module:  PrioritytStrategy
//
// Implementation of the DefaultStrategy template.
//
// Copyright (c) 2006-2011, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef Foundation_PriorityStrategy_INCLUDED
#define Foundation_PriorityStrategy_INCLUDED


#include <vector>
#include "Poco/NotificationStrategy.h"
#include "Poco/SharedPtr.h"


namespace Poco
{


template <class TArgs, class TDelegate>
class PriorityStrategy : public NotificationStrategy<TArgs, TDelegate>
/// NotificationStrategy for PriorityEvent.
///
/// Delegates are kept in a std::vector<>, ordered
/// by their priority.
{
public:
    typedef TDelegate * DelegateHandle;
    typedef SharedPtr<TDelegate> DelegatePtr;
    typedef std::vector<DelegatePtr> Delegates;
    typedef typename Delegates::iterator Iterator;

public:
    PriorityStrategy() { }

    PriorityStrategy(const PriorityStrategy & s) : _delegates(s._delegates) { }

    ~PriorityStrategy() { }

    void notify(const void * sender, TArgs & arguments)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            (*it)->notify(sender, arguments);
        }
    }

    DelegateHandle add(const TDelegate & delegate)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            if ((*it)->priority() > delegate.priority())
            {
                DelegatePtr pDelegate(static_cast<TDelegate *>(delegate.clone()));
                _delegates.insert(it, pDelegate);
                return pDelegate.get();
            }
        }
        DelegatePtr pDelegate(static_cast<TDelegate *>(delegate.clone()));
        _delegates.push_back(pDelegate);
        return pDelegate.get();
    }

    void remove(const TDelegate & delegate)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            if (delegate.equals(**it))
            {
                (*it)->disable();
                _delegates.erase(it);
                return;
            }
        }
    }

    void remove(DelegateHandle delegateHandle)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            if (*it == delegateHandle)
            {
                (*it)->disable();
                _delegates.erase(it);
                return;
            }
        }
    }

    PriorityStrategy & operator=(const PriorityStrategy & s)
    {
        if (this != &s)
        {
            _delegates = s._delegates;
        }
        return *this;
    }

    void clear()
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            (*it)->disable();
        }
        _delegates.clear();
    }

    bool empty() const { return _delegates.empty(); }

protected:
    Delegates _delegates;
};


template <class TDelegate>
class PriorityStrategy<void, TDelegate>
/// NotificationStrategy for PriorityEvent.
///
/// Delegates are kept in a std::vector<>, ordered
/// by their priority.
{
public:
    typedef TDelegate * DelegateHandle;
    typedef SharedPtr<TDelegate> DelegatePtr;
    typedef std::vector<DelegatePtr> Delegates;
    typedef typename Delegates::iterator Iterator;

public:
    void notify(const void * sender)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            (*it)->notify(sender);
        }
    }

    DelegateHandle add(const TDelegate & delegate)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            if ((*it)->priority() > delegate.priority())
            {
                DelegatePtr pDelegate(static_cast<TDelegate *>(delegate.clone()));
                _delegates.insert(it, pDelegate);
                return pDelegate.get();
            }
        }
        DelegatePtr pDelegate(static_cast<TDelegate *>(delegate.clone()));
        _delegates.push_back(pDelegate);
        return pDelegate.get();
    }

    void remove(const TDelegate & delegate)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            if (delegate.equals(**it))
            {
                (*it)->disable();
                _delegates.erase(it);
                return;
            }
        }
    }

    void remove(DelegateHandle delegateHandle)
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            if (*it == delegateHandle)
            {
                (*it)->disable();
                _delegates.erase(it);
                return;
            }
        }
    }

    PriorityStrategy & operator=(const PriorityStrategy & s)
    {
        if (this != &s)
        {
            _delegates = s._delegates;
        }
        return *this;
    }

    void clear()
    {
        for (Iterator it = _delegates.begin(); it != _delegates.end(); ++it)
        {
            (*it)->disable();
        }
        _delegates.clear();
    }

    bool empty() const { return _delegates.empty(); }

protected:
    Delegates _delegates;
};


} // namespace Poco


#endif // Foundation_PriorityStrategy_INCLUDED