1 /*
2 * Copyright (c) 1998, 2013, 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
26 /*
27 * (C) Copyright Taligent, Inc. 1996 - 1997, All Rights Reserved
28 * (C) Copyright IBM Corp. 1996 - 1998, All Rights Reserved
29 *
30 * The original version of this source code and documentation is
31 * copyrighted and owned by Taligent, Inc., a wholly-owned subsidiary
32 * of IBM. These materials are provided under terms of a License
33 * Agreement between Taligent and Sun. This technology is protected
34 * by multiple US and International patents.
35 *
36 * This notice and attribution to Taligent may not be removed.
37 * Taligent is a registered trademark of Taligent, Inc.
38 *
39 */
40
41 package java.awt.font;
42
43 import java.awt.geom.AffineTransform;
44 import java.io.Serializable;
45 import java.io.ObjectStreamException;
46
47 /**
48 * The {@code TransformAttribute} class provides an immutable
49 * wrapper for a transform so that it is safe to use as an attribute.
50 */
51 public final class TransformAttribute implements Serializable {
52
53 /**
54 * The {@code AffineTransform} for this
55 * {@code TransformAttribute}, or {@code null}
56 * if {@code AffineTransform} is the identity transform.
57 */
58 private AffineTransform transform;
59
60 /**
61 * Wraps the specified transform. The transform is cloned and a
62 * reference to the clone is kept. The original transform is unchanged.
63 * If null is passed as the argument, this constructor behaves as though
64 * it were the identity transform. (Note that it is preferable to use
65 * {@link #IDENTITY} in this case.)
66 * @param transform the specified {@link AffineTransform} to be wrapped,
67 * or null.
68 */
69 public TransformAttribute(AffineTransform transform) {
70 if (transform != null && !transform.isIdentity()) {
71 this.transform = new AffineTransform(transform);
72 }
73 }
74
75 /**
76 * Returns a copy of the wrapped transform.
77 * @return an {@code AffineTransform} that is a copy of the wrapped
78 * transform of this {@code TransformAttribute}.
79 */
80 public AffineTransform getTransform() {
81 AffineTransform at = transform;
82 return (at == null) ? new AffineTransform() : new AffineTransform(at);
83 }
84
85 /**
86 * Returns {@code true} if the wrapped transform is
87 * an identity transform.
88 * @return {@code true} if the wrapped transform is
89 * an identity transform; {@code false} otherwise.
90 * @since 1.4
91 */
92 public boolean isIdentity() {
93 return transform == null;
94 }
95
96 /**
97 * A {@code TransformAttribute} representing the identity transform.
98 * @since 1.6
99 */
100 public static final TransformAttribute IDENTITY = new TransformAttribute(null);
101
102 private void writeObject(java.io.ObjectOutputStream s)
103 throws java.lang.ClassNotFoundException,
104 java.io.IOException
105 {
106 // sigh -- 1.3 expects transform is never null, so we need to always write one out
107 if (this.transform == null) {
108 this.transform = new AffineTransform();
109 }
110 s.defaultWriteObject();
111 }
112
113 /*
114 * @since 1.6
115 */
116 private Object readResolve() throws ObjectStreamException {
117 if (transform == null || transform.isIdentity()) {
118 return IDENTITY;
119 }
120 return this;
121 }
122
123 // Added for serial backwards compatibility (4348425)
124 static final long serialVersionUID = 3356247357827709530L;
125
126 /**
127 * @since 1.6
128 */
129 public int hashCode() {
130 return transform == null ? 0 : transform.hashCode();
131 }
132
133 /**
134 * Returns {@code true} if rhs is a {@code TransformAttribute}
135 * whose transform is equal to this {@code TransformAttribute}'s
136 * transform.
137 * @param rhs the object to compare to
138 * @return {@code true} if the argument is a {@code TransformAttribute}
139 * whose transform is equal to this {@code TransformAttribute}'s
140 * transform.
141 * @since 1.6
142 */
143 public boolean equals(Object rhs) {
144 if (rhs != null) {
145 try {
146 TransformAttribute that = (TransformAttribute)rhs;
147 if (transform == null) {
148 return that.transform == null;
149 }
150 return transform.equals(that.transform);
151 }
152 catch (ClassCastException e) {
153 }
154 }
155 return false;
156 }
157 }