1 /*
2 * Copyright (c) 2016, 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 package java.lang.module;
27
28 import java.util.Objects;
29 import java.util.Set;
30
31 /**
32 * A module in a graph of <em>resolved modules</em>.
33 *
34 * <p> {@code ResolvedModule} defines the {@link #configuration configuration}
35 * method to get the configuration that the resolved module is in. It defines
36 * the {@link #reference() reference} method to get the reference to the
37 * module's content.
38 *
39 * @since 9
40 * @see Configuration#modules()
41 */
42 public final class ResolvedModule {
43
44 private final Configuration cf;
45 private final ModuleReference mref;
46
47 ResolvedModule(Configuration cf, ModuleReference mref) {
48 this.cf = Objects.requireNonNull(cf);
49 this.mref = Objects.requireNonNull(mref);
50 }
51
52 /**
53 * Returns the configuration that this resolved module is in.
54 *
55 * @return The configuration that this resolved module is in
56 */
57 public Configuration configuration() {
58 return cf;
59 }
60
61 /**
62 * Returns the reference to the module's content.
63 *
64 * @return The reference to the module's content
65 */
66 public ModuleReference reference() {
67 return mref;
68 }
69
70 /**
71 * Returns the module descriptor.
72 *
73 * This convenience method is the equivalent to invoking:
74 * <pre> {@code
75 * reference().descriptor()
76 * }</pre>
77 *
78 * @return The module descriptor
79 */
80 ModuleDescriptor descriptor() {
81 return reference().descriptor();
82 }
83
84 /**
85 * Returns the module name.
86 *
87 * This convenience method is the equivalent to invoking:
88 * <pre> {@code
89 * reference().descriptor().name()
90 * }</pre>
91 *
92 * @return The module name
93 */
94 public String name() {
95 return reference().descriptor().name();
96 }
97
98 /**
99 * Returns the set of resolved modules that this resolved module reads.
100 *
101 * @return A possibly-empty unmodifiable set of resolved modules that
102 * this resolved module reads
103 */
104 public Set<ResolvedModule> reads() {
105 return cf.reads(this);
106 }
107
108 /**
109 * Computes a hash code for this resolved module.
110 *
111 * <p> The hash code is based upon the components of the resolved module
112 * and satisfies the general contract of the {@link Object#hashCode
113 * Object.hashCode} method. </p>
114 *
115 * @return The hash-code value for this resolved module
116 */
117 @Override
118 public int hashCode() {
119 return cf.hashCode() ^ mref.hashCode();
120 }
121
122 /**
123 * Tests this resolved module for equality with the given object.
124 *
125 * <p> If the given object is not a {@code ResolvedModule} then this
126 * method returns {@code false}. Two {@code ResolvedModule} objects are
127 * equal if they are in the same configuration and have equal references
128 * to the module content. </p>
129 *
130 * <p> This method satisfies the general contract of the {@link
131 * java.lang.Object#equals(Object) Object.equals} method. </p>
132 *
133 * @param ob
134 * the object to which this object is to be compared
135 *
136 * @return {@code true} if, and only if, the given object is a module
137 * reference that is equal to this module reference
138 */
139 @Override
140 public boolean equals(Object ob) {
141 if (!(ob instanceof ResolvedModule))
142 return false;
143
144 ResolvedModule that = (ResolvedModule) ob;
145 return Objects.equals(this.cf, that.cf)
146 && Objects.equals(this.mref, that.mref);
147 }
148
149 /**
150 * Returns a string describing this resolved module.
151 *
152 * @return A string describing this resolved module
153 */
154 @Override
155 public String toString() {
156 return System.identityHashCode(cf) + "/" + name();
157 }
158
159 }