observe.cpp

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#ifdef HAVE_CONFIG_H
#include <../../nrnconf.h>
#endif
/*
 * Copyright (c) 1992 Stanford University
 * Copyright (c) 1992 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and 
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Stanford and Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Stanford and Silicon Graphics.
 * 
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 *
 * IN NO EVENT SHALL STANFORD OR SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF 
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE 
 * OF THIS SOFTWARE.
 */

/*
 * Observable - object to observe
 */

#include <InterViews/observe.h>
#include <OS/list.h>

declarePtrList(ObserverList,Observer)
implementPtrList(ObserverList,Observer)

Observable::Observable() {
    observers_ = nil;
}

Observable::~Observable() {
    ObserverList* list = observers_;
    if (list != nil) {
    // in case a disconnect removes items from the ObserverList
    for (long i = list->count() - 1; i >= 0; --i) {
        list->item(i)->disconnect(this);
        if (i > list->count()) { i = list->count(); }
    }
    delete list;
    }
}

void Observable::attach(Observer* o) {
    ObserverList* list = observers_;
    if (list == nil) {
    list = new ObserverList(5);
    observers_ = list;
    }
    list->append(o);
}

void Observable::detach(Observer* o) {
    ObserverList* list = observers_;
    if (list != nil) {
    for (ListUpdater(ObserverList) i(*list); i.more(); i.next()) {
        if (i.cur() == o) {
        i.remove_cur();
        break;
        }
    }
    }
}

void Observable::notify() {
    ObserverList* list = observers_;
    if (list != nil) {
    for (ListItr(ObserverList) i(*list); i.more(); i.next()) {
        i.cur()->update(this);
    }
    }
}

Observer::Observer() { }
Observer::~Observer() { }
void Observer::update(Observable*) { }
void Observer::disconnect(Observable*) { }