1 /*
 2  * Copyright (c) 2001, 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 package jdk.internal.reflect;
27 
28 import java.lang.reflect.Constructor;
29 import java.lang.reflect.InvocationTargetException;
30 import jdk.internal.misc.Unsafe;
31 import sun.reflect.misc.ReflectUtil;
32 
33 /** Used only for the first few invocations of a Constructor;
34     afterward, switches to bytecode-based implementation */
35 
36 class NativeConstructorAccessorImpl extends ConstructorAccessorImpl {
37     private static final Unsafe U = Unsafe.getUnsafe();
38     private static final long GENERATED_OFFSET
39         = U.objectFieldOffset(NativeConstructorAccessorImpl.class, "generated");
40 
41     private final Constructor<?> c;
42     private final DelegatingConstructorAccessorImpl parent;
43     private int numInvocations;
44     private volatile int generated;
45 
46     NativeConstructorAccessorImpl(Constructor<?> c) {
47         this.c = c;
48         this.parent = new DelegatingConstructorAccessorImpl(this);
49     }
50 
51     public Object newInstance(Object[] args)
52         throws InstantiationException,
53                IllegalArgumentException,
54                InvocationTargetException
55     {
56         boolean generate = false;
57         if (!c.getDeclaringClass().isHidden()) {
58             if (Thread.currentThread().isVirtual()) {
59                 generate = true;
60             } else {
61                 if (++numInvocations > ReflectionFactory.inflationThreshold()
62                         && generated == 0
63                         && U.compareAndSetInt(this, GENERATED_OFFSET, 0, 1)) {
64                     generate = true;
65                 }
66             }
67         }
68 
69         if (generate) {
70             // class initializer may not have run
71             Unsafe.getUnsafe().ensureClassInitialized(c.getDeclaringClass());
72 
73             ConstructorAccessorImpl acc;
74             try {
75                 acc = NewAccessorImplFactory.newConstructorAccessorImpl(c);
76             } catch (Throwable t) {
77                 // newConstructorAccessorImpl failed, restore generated to 0
78                 generated = 0;
79                 throw t;
80             }
81 
82             parent.setDelegate(acc);
83             return acc.newInstance(args);
84         }
85 
86         return newInstance0(c, args);
87     }
88 
89     DelegatingConstructorAccessorImpl getParent() {
90         return parent;
91     }
92 
93     private static native Object newInstance0(Constructor<?> c, Object[] args)
94         throws InstantiationException,
95                IllegalArgumentException,
96                InvocationTargetException;
97 }