ConstructorFinder.java revision 13901:b2a69d66dc65 
1/*
2 * Copyright (c) 2008, 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
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24 */
25package com.sun.beans.finder;
26
27import com.sun.beans.util.Cache;
28
29import java.lang.reflect.Constructor;
30import java.lang.reflect.Modifier;
31
32import static com.sun.beans.util.Cache.Kind.SOFT;
33import static sun.reflect.misc.ReflectUtil.isPackageAccessible;
34
35/**
36 * This utility class provides {@code static} methods
37 * to find a public constructor with specified parameter types
38 * in specified class.
39 *
40 * @since 1.7
41 *
42 * @author Sergey A. Malenkov
43 */
44public final class ConstructorFinder extends AbstractFinder<Constructor<?>> {
45    private static final Cache<Signature, Constructor<?>> CACHE = new Cache<Signature, Constructor<?>>(SOFT, SOFT) {
46        @Override
47        public Constructor<?> create(Signature signature) {
48            try {
49                ConstructorFinder finder = new ConstructorFinder(signature.getArgs());
50                return finder.find(signature.getType().getConstructors());
51            }
52            catch (Exception exception) {
53                throw new SignatureException(exception);
54            }
55        }
56    };
57
58    /**
59     * Finds public constructor
60     * that is declared in public class.
61     *
62     * @param type  the class that can have constructor
63     * @param args  parameter types that is used to find constructor
64     * @return object that represents found constructor
65     * @throws NoSuchMethodException if constructor could not be found
66     *                               or some constructors are found
67     */
68    public static Constructor<?> findConstructor(Class<?> type, Class<?>...args) throws NoSuchMethodException {
69        if (type.isPrimitive()) {
70            throw new NoSuchMethodException("Primitive wrapper does not contain constructors");
71        }
72        if (type.isInterface()) {
73            throw new NoSuchMethodException("Interface does not contain constructors");
74        }
75        if (!FinderUtils.isExported(type)) {
76            throw new NoSuchMethodException("Class is not accessible");
77        }
78        if (Modifier.isAbstract(type.getModifiers())) {
79            throw new NoSuchMethodException("Abstract class cannot be instantiated");
80        }
81        if (!Modifier.isPublic(type.getModifiers()) || !isPackageAccessible(type)) {
82            throw new NoSuchMethodException("Class is not accessible");
83        }
84        PrimitiveWrapperMap.replacePrimitivesWithWrappers(args);
85        Signature signature = new Signature(type, args);
86
87        try {
88            return CACHE.get(signature);
89        }
90        catch (SignatureException exception) {
91            throw exception.toNoSuchMethodException("Constructor is not found");
92        }
93    }
94
95    /**
96     * Creates constructor finder with specified array of parameter types.
97     *
98     * @param args  the array of parameter types
99     */
100    private ConstructorFinder(Class<?>[] args) {
101        super(args);
102    }
103}
104