68 lines
1.7 KiB
C++
68 lines
1.7 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#ifndef ULTIMA4_CORE_OBSERVER_H
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#define ULTIMA4_CORE_OBSERVER_H
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namespace Ultima {
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namespace Ultima4 {
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template<class O, class A>
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class Observable;
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class NoArg;
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/**
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* This is the interface a class must implement to watch an
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* Observable.
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*/
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template<class O, class A = NoArg *>
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class Observer {
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public:
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virtual void update(O observable, A arg) = 0;
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virtual ~Observer() {}
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};
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/**
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* A specialized observer for watching observables that don't use the
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* "arg" parameter to update.
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*/
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template<class O>
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class Observer<O, NoArg *> {
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public:
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virtual void update(O observable, NoArg *arg) {
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update(observable);
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}
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virtual void update(O observable) = 0;
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virtual ~Observer() {}
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};
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/**
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* Just an empty marker class to identify observers that take no args
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* on update.
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*/
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class NoArg {
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};
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} // End of namespace Ultima4
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} // End of namespace Ultima
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#endif
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