1/*
2 * Copyright (c) 2008, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24package com.sun.hotspot.igv.data;
25
26import java.util.ArrayList;
27import java.util.List;
28
29/**
30 *
31 * @author Thomas Wuerthinger
32 */
33public abstract class Event<L> {
34
35    private List<L> listener;
36    private boolean fireEvents;
37    private boolean eventWasFired;
38
39    public Event() {
40        listener = new ArrayList<>();
41        fireEvents = true;
42    }
43
44    public void addListener(L l) {
45        listener.add(l);
46    }
47
48    /**
49     * Remove listener
50     * @param l
51     */
52    public void removeListener(final L l) {
53        listener.remove(l);
54    }
55
56    public void fire() {
57        if(fireEvents) {
58            List<L> tmpList = new ArrayList<>(listener);
59            for (L l : tmpList) {
60                fire(l);
61            }
62        } else {
63            eventWasFired = true;
64        }
65    }
66
67    public void beginAtomic() {
68        assert fireEvents : "endAtomic has to be called before another beginAtomic may be called";
69        this.fireEvents = false;
70        this.eventWasFired = false;
71    }
72
73    public void endAtomic() {
74        assert !fireEvents : "beginAtomic has to be called first";
75        this.fireEvents = true;
76        if(eventWasFired) {
77            fire();
78        }
79    }
80
81    protected abstract void fire(L l);
82}
83