1/*
2 * Copyright (c) 2009, 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 */
25package com.sun.beans.finder;
26
27/**
28 * This is utility class that provides basic functionality
29 * to find an auxiliary class for a JavaBean specified by its type.
30 *
31 * @since 1.7
32 *
33 * @author Sergey A. Malenkov
34 */
35class InstanceFinder<T> {
36
37    private static final String[] EMPTY = { };
38
39    private final Class<? extends T> type;
40    private final boolean allow;
41    private final String suffix;
42    private volatile String[] packages;
43
44    InstanceFinder(Class<? extends T> type, boolean allow, String suffix, String... packages) {
45        this.type = type;
46        this.allow = allow;
47        this.suffix = suffix;
48        this.packages = packages.clone();
49    }
50
51    public String[] getPackages() {
52        return this.packages.clone();
53    }
54
55    public void setPackages(String... packages) {
56        this.packages = (packages != null) && (packages.length > 0)
57                ? packages.clone()
58                : EMPTY;
59    }
60
61    public T find(Class<?> type) {
62        if (type == null) {
63            return null;
64        }
65        String name = type.getName() + this.suffix;
66        T object = instantiate(type, name);
67        if (object != null) {
68            return object;
69        }
70        if (this.allow) {
71            object = instantiate(type, null);
72            if (object != null) {
73                return object;
74            }
75        }
76        int index = name.lastIndexOf('.') + 1;
77        if (index > 0) {
78            name = name.substring(index);
79        }
80        for (String prefix : this.packages) {
81            object = instantiate(type, prefix, name);
82            if (object != null) {
83                return object;
84            }
85        }
86        return null;
87    }
88
89    @SuppressWarnings("deprecation")
90    protected T instantiate(Class<?> type, String name) {
91        if (type != null) {
92            try {
93                if (name != null) {
94                    type = ClassFinder.findClass(name, type.getClassLoader());
95                }
96                if (this.type.isAssignableFrom(type)) {
97                    @SuppressWarnings("unchecked")
98                    T tmp = (T) type.newInstance();
99                    return tmp;
100                }
101            }
102            catch (Exception exception) {
103                // ignore any exceptions
104            }
105        }
106        return null;
107    }
108
109    protected T instantiate(Class<?> type, String prefix, String name) {
110        return instantiate(type, prefix + '.' + name);
111    }
112}
113