1 /*
2 * Copyright (c) 1996, 2014, 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. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package java.awt;
26
27 /**
28 * Defines an interface for classes that know how to layout Containers
29 * based on a layout constraints object.
30 *
31 * This interface extends the LayoutManager interface to deal with layouts
32 * explicitly in terms of constraint objects that specify how and where
33 * components should be added to the layout.
34 * <p>
35 * This minimal extension to LayoutManager is intended for tool
36 * providers who wish to the creation of constraint-based layouts.
37 * It does not yet provide full, general support for custom
38 * constraint-based layout managers.
39 *
40 * @see LayoutManager
41 * @see Container
42 *
43 * @author Jonni Kanerva
44 */
45 public interface LayoutManager2 extends LayoutManager {
46
47 /**
48 * Adds the specified component to the layout, using the specified
49 * constraint object.
50 * @param comp the component to be added
51 * @param constraints where/how the component is added to the layout.
52 */
53 void addLayoutComponent(Component comp, Object constraints);
54
55 /**
56 * Calculates the maximum size dimensions for the specified container,
57 * given the components it contains.
58 * @see java.awt.Component#getMaximumSize
59 * @see LayoutManager
60 * @param target the target container
61 * @return the maximum size of the container
62 */
63 public Dimension maximumLayoutSize(Container target);
64
65 /**
66 * Returns the alignment along the x axis. This specifies how
67 * the component would like to be aligned relative to other
68 * components. The value should be a number between 0 and 1
69 * where 0 represents alignment along the origin, 1 is aligned
70 * the furthest away from the origin, 0.5 is centered, etc.
71 *
72 * @param target the target container
73 * @return the x-axis alignment preference
74 */
75 public float getLayoutAlignmentX(Container target);
76
77 /**
78 * Returns the alignment along the y axis. This specifies how
79 * the component would like to be aligned relative to other
80 * components. The value should be a number between 0 and 1
81 * where 0 represents alignment along the origin, 1 is aligned
82 * the furthest away from the origin, 0.5 is centered, etc.
83 *
84 * @param target the target container
85 * @return the y-axis alignment preference
86 */
87 public float getLayoutAlignmentY(Container target);
88
89 /**
90 * Invalidates the layout, indicating that if the layout manager
91 * has cached information it should be discarded.
92 * @param target the target container
93 */
94 public void invalidateLayout(Container target);
95
96 }