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 */
25package java.lang;
26
27import java.lang.module.Configuration;
28import java.lang.module.ModuleReference;
29import java.net.URI;
30
31/**
32 * A NamedPackage represents a package by name in a specific module.
33 *
34 * A class loader will automatically create NamedPackage for each
35 * package when a class is defined.  Package object is lazily
36 * defined until Class::getPackage, Package::getPackage(s), or
37 * ClassLoader::getDefinedPackage(s) method is called.
38 *
39 * NamedPackage allows ClassLoader to keep track of the runtime
40 * packages with minimal footprint and avoid constructing Package
41 * object.
42 */
43class NamedPackage {
44    private final String name;
45    private final Module module;
46
47    NamedPackage(String pn, Module module) {
48        if (pn.isEmpty() && module.isNamed()) {
49            throw new InternalError("unnamed package in  " + module);
50        }
51        this.name = pn.intern();
52        this.module = module;
53    }
54
55    /**
56     * Returns the name of this package.
57     */
58    String packageName() {
59        return name;
60    }
61
62    /**
63     * Returns the module of this named package.
64     */
65    Module module() {
66        return module;
67    }
68
69    /**
70     * Returns the location of the module if this named package is in
71     * a named module; otherwise, returns null.
72     */
73    URI location() {
74        if (module.isNamed() && module.getLayer() != null) {
75            Configuration cf = module.getLayer().configuration();
76            ModuleReference mref
77                = cf.findModule(module.getName()).get().reference();
78            return mref.location().orElse(null);
79        }
80        return null;
81    }
82
83    /**
84     * Creates a Package object of the given name and module.
85     */
86    static Package toPackage(String name, Module module) {
87        return new Package(name, module);
88    }
89}
90