1 /*
2 * Entreri, an entity-component framework in Java
3 *
4 * Copyright (c) 2013, Michael Ludwig
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without modification,
8 * are permitted provided that the following conditions are met:
9 *
10 * Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 * Redistributions in binary form must reproduce the above copyright notice,
13 * this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
20 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
23 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27 package com.lhkbob.entreri;
28
29 /**
30 * Owner is a listener and tag interface so that {@link Ownable} implementations can
31 * report ownership changes to their owners. This is used by both Components and Entities
32 * to track which objects they own and disown them when they are removed from the
33 * EntitySystem.
34 *
35 * @author Michael Ludwig
36 */
37 public interface Owner {
38 /**
39 * Notify this Owner that it is now <var>obj</var>'s owner. This must only be called
40 * by {@link Ownable} implementations in response to calls to {@link
41 * Ownable#setOwner(Owner)}.
42 * <p/>
43 * This method returns the true Owner instance, to allow for flyweight objects to act
44 * as Owners. In this case, they will return the canonical owner for the datum they
45 * represent. In regular cases, this will return itself after recording ownership.
46 *
47 * @param obj The newly owned object
48 *
49 * @return The actual owner in the event that the owner was a flyweight object
50 */
51 public Owner notifyOwnershipGranted(Ownable obj);
52
53 /**
54 * <p/>
55 * Notify this Owner that it is no longer <var>obj</var>'s owner. This must only be
56 * called by {@link Ownable} implementations in response to calls to {@link
57 * Ownable#setOwner(Owner)}.
58 * <p/>
59 * Ownership is revoked when the Ownable is assigned a new owner, or the null owner
60 * but was previously owned by this instance.
61 *
62 * @param obj The disowned object
63 */
64 public void notifyOwnershipRevoked(Ownable obj);
65 }