item_listener.h

/*
 * Copyright (c) 2008-2025, Hazelcast, Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#pragma once
 
#include <utility>
#include <functional>
 
#include "hazelcast/util/export.h"
#include "hazelcast/util/noop.h"
#include "hazelcast/util/type_traits.h"
 
#if defined(WIN32) || defined(_WIN32) || defined(WIN64) || defined(_WIN64)
#pragma warning(push)
#pragma warning(disable : 4251) // for dll export
#endif
 
namespace hazelcast {
namespace client {
class item_event;
 
namespace impl {
template<typename>
class item_event_handler;
}

class HAZELCAST_API item_listener final
{
public:
    template<typename Handler,
             typename = util::enable_if_rvalue_ref_trait<Handler&&>>
    item_listener& on_added(Handler&& h) &
    {
        added_ = std::forward<Handler>(h);
        return *this;
    }

    template<typename Handler,
             typename = util::enable_if_rvalue_ref_trait<Handler&&>>
    item_listener&& on_added(Handler&& h) &&
    {
        on_added(std::forward<Handler>(h));
        return std::move(*this);
    }

    template<typename Handler>
    item_listener& on_removed(Handler&& h) &
    {
        removed_ = std::forward<Handler>(h);
        return *this;
    }

    template<typename Handler>
    item_listener&& on_removed(Handler&& h) &&
    {
        on_removed(std::forward<Handler>(h));
        return std::move(*this);
    }
 
private:
    using HandlerType = std::function<void(item_event&&)>;
    HandlerType added_ = util::noop<item_event&&>,
                removed_ = util::noop<item_event&&>;
 
    template<typename>
    friend class impl::item_event_handler;
};
} // namespace client
} // namespace hazelcast
 
#if defined(WIN32) || defined(_WIN32) || defined(WIN64) || defined(_WIN64)
#pragma warning(pop)
#endif