1 /*
2  * Copyright (c) 2024 Huawei Device Co., Ltd.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at
6  *
7  *     http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #ifndef META_INTERFACE_ICONTAINER_OBSERVER_H
17 #define META_INTERFACE_ICONTAINER_OBSERVER_H
18 
19 #include <meta/interface/intf_container.h>
20 
21 META_BEGIN_NAMESPACE()
22 
23 META_REGISTER_INTERFACE(IContainerObserver, "19ddad68-4743-4902-a816-a5f4d5812c7e")
24 
25 /**
26  * @brief The IContainerObserver interface can be implemented by classes which
27  *        can be used to monitor the container hierarchy of an IContainer.
28  *
29  *        The difference between IContainerObserver events and IContainer events
30  *        is that IContainer defines events only for the immediate children of
31  *        the IContainer, while IContainerObserver events are fired as a response
32  *        to changes in the entire child hierarchy.
33  */
34 class IContainerObserver : public CORE_NS::IInterface {
35     META_INTERFACE(CORE_NS::IInterface, IContainerObserver)
36 public:
37     /**
38      * @brief Sets the container to observe.
39      * @param container The target container.
40      */
41     virtual void SetContainer(const IContainer::Ptr& container) = 0;
42     /**
43      * @brief Invoked when a child is added to any container in the hierarchy.
44      */
45     META_EVENT(IOnChildChanged, OnDescendantAdded)
46     /**
47      * @brief Invoked when a child is removed from any container in the hierarchy.
48      */
49     META_EVENT(IOnChildChanged, OnDescendantRemoved)
50     /**
51      * @brief Invoked when a child is moved within any container in the hierarchy.
52      */
53     META_EVENT(IOnChildMoved, OnDescendantMoved)
54 };
55 
56 META_END_NAMESPACE()
57 
58 #endif // META_INTERFACE_ICONTAINER_OBSERVER_H
59