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.property;
28
29 /**
30 * <p/>
31 * A PropertyFactory is a simple factory that can be used to create Property instances.
32 * Additionally, it is used when decorating a ComponentData type in an EntitySystem to
33 * ensure that each decoration event gets a unique property instance.
34 * <p/>
35 * PropertyFactory implementations must have a no-argument constructor or a constructor
36 * that takes an {@link Attributes} as its only argument. The constructor does not need to
37 * be public.
38 *
39 * @param <T> The Property type created
40 *
41 * @author Michael Ludwig
42 */
43 public interface PropertyFactory<T extends Property> {
44 /**
45 * Return a new Property instance. This must be a new instance that has not been
46 * returned previously or the entity framework will have undefined behavior.
47 *
48 * @return A new Property of type T
49 */
50 public T create();
51
52 /**
53 * Set the default value that the component at the specified <var>index</var> will see
54 * before it's init() method is invoked. In some cases, this could be used in-place of
55 * initializing in init() method.
56 *
57 * @param property The property whose value will be updated
58 * @param index The component index to be updated
59 */
60 public void setDefaultValue(T property, int index);
61
62 /**
63 * Copy the value from <var>src</var> at component index, <var>srcIndex</var> to
64 * <var>dst</var> at <var>dstIndex</var>. This is used when a component is created and
65 * cloned from a template with {@link com.lhkbob.entreri.Entity#add(com.lhkbob.entreri.Component)}.
66 * For many cases a plain copy-by-value or copy-by-reference is sufficient, but some
67 * component types might require more complicated cloning rules.
68 *
69 * @param src The source property that is being cloned
70 * @param srcIndex The index into src of the component being cloned
71 * @param dst The destination property created from the template
72 * @param dstIndex The index into dst of the component being created
73 */
74 public void clone(T src, int srcIndex, T dst, int dstIndex);
75 }