StdInstantiatorStrategy.java revision eebfcaffb2d52b214abfdb1c0102395c88c9db54 
1/**
2 * Copyright 2006-2017 the original author or authors.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16package org.objenesis.strategy;
17
18import org.objenesis.instantiator.ObjectInstantiator;
19import org.objenesis.instantiator.android.Android10Instantiator;
20import org.objenesis.instantiator.android.Android17Instantiator;
21import org.objenesis.instantiator.android.Android18Instantiator;
22import org.objenesis.instantiator.basic.AccessibleInstantiator;
23import org.objenesis.instantiator.basic.ObjectInputStreamInstantiator;
24import org.objenesis.instantiator.gcj.GCJInstantiator;
25import org.objenesis.instantiator.perc.PercInstantiator;
26import org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator;
27import org.objenesis.instantiator.sun.UnsafeFactoryInstantiator;
28
29import java.io.Serializable;
30
31import static org.objenesis.strategy.PlatformDescription.*;
32
33/**
34 * Guess the best instantiator for a given class. The instantiator will instantiate the class
35 * without calling any constructor. Currently, the selection doesn't depend on the class. It relies
36 * on the
37 * <ul>
38 * <li>JVM version</li>
39 * <li>JVM vendor</li>
40 * <li>JVM vendor version</li>
41 * </ul>
42 * However, instantiators are stateful and so dedicated to their class.
43 *
44 * @author Henri Tremblay
45 * @see ObjectInstantiator
46 */
47public class StdInstantiatorStrategy extends BaseInstantiatorStrategy {
48
49   /**
50    * Return an {@link ObjectInstantiator} allowing to create instance without any constructor being
51    * called.
52    *
53    * @param type Class to instantiate
54    * @return The ObjectInstantiator for the class
55    */
56   public <T> ObjectInstantiator<T> newInstantiatorOf(Class<T> type) {
57
58      if(PlatformDescription.isThisJVM(HOTSPOT) || PlatformDescription.isThisJVM(OPENJDK)) {
59         if(PlatformDescription.isGoogleAppEngine()) {
60            if(Serializable.class.isAssignableFrom(type)) {
61               return new ObjectInputStreamInstantiator<T>(type);
62            }
63            return new AccessibleInstantiator<T>(type);
64         }
65         // The UnsafeFactoryInstantiator would also work. But according to benchmarks, it is 2.5
66         // times slower. So I prefer to use this one
67         return new SunReflectionFactoryInstantiator<T>(type);
68      }
69      else if(PlatformDescription.isThisJVM(DALVIK)) {
70         if(PlatformDescription.isAndroidOpenJDK()) {
71            // Starting at Android N which is based on OpenJDK
72            return new UnsafeFactoryInstantiator<T>(type);
73         }
74         if(ANDROID_VERSION <= 10) {
75            // Android 2.3 Gingerbread and lower
76            return new Android10Instantiator<T>(type);
77         }
78         if(ANDROID_VERSION <= 17) {
79            // Android 3.0 Honeycomb to 4.2 Jelly Bean
80            return new Android17Instantiator<T>(type);
81         }
82         // Android 4.3 until Android N
83         return new Android18Instantiator<T>(type);
84      }
85      else if(PlatformDescription.isThisJVM(JROCKIT)) {
86         // JRockit is compliant with HotSpot
87         return new SunReflectionFactoryInstantiator<T>(type);
88      }
89      else if(PlatformDescription.isThisJVM(GNU)) {
90         return new GCJInstantiator<T>(type);
91      }
92      else if(PlatformDescription.isThisJVM(PERC)) {
93         return new PercInstantiator<T>(type);
94      }
95
96      // Fallback instantiator, should work with most modern JVM
97      return new UnsafeFactoryInstantiator<T>(type);
98
99   }
100}
101