1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
/*
* Copyright 2006-2012 Amazon Technologies, Inc. or its affiliates.
* Amazon, Amazon.com and Carbonado are trademarks or registered trademarks
* of Amazon Technologies, Inc. or its affiliates. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.amazon.carbonado.util;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.UndeclaredThrowableException;
import java.util.Map;
import org.cojen.classfile.ClassFile;
import org.cojen.classfile.CodeBuilder;
import org.cojen.classfile.TypeDesc;
import org.cojen.util.ClassInjector;
import org.cojen.util.WeakIdentityMap;
/**
* Generates code to invoke constructors. This is a replacement for {@link
* java.lang.reflect.Constructor} which is easier to use and performs
* better. In one tested situation, overall performance was improved by about
* 10%.
*
* <p>QuickConstructorGenerator is not general purpose however, as the
* parameters to the constructor must be known, and the constructor must be
* public. It is intended to be used for constructing instances of
* auto-generated classes. The exact parameters may be known at compile time,
* but the actual object type is not.
*
* @author Brian S O'Neill
* @deprecated use {@link org.cojen.util.QuickConstructorGenerator}
*/
@Deprecated
public class QuickConstructorGenerator {
// Map<factory class, Map<object type, factory instance>>
@SuppressWarnings("unchecked")
private static Map<Class<?>, SoftValuedCache<Class<?>, Object>> cCache = new WeakIdentityMap();
/**
* Returns a factory instance for one type of object. Each method in the
* interface defines a constructor via its parameters. Any checked
* exceptions declared thrown by the constructor must also be declared by
* the method. The method return types can be the same type as the
* constructed object or a supertype.
*
* <p>Here is a contrived example for constructing strings. In practice,
* such a string factory is is useless, since the "new" operator can be
* invoked directly.
*
* <pre>
* public interface StringFactory {
* String newEmptyString();
*
* String newStringFromChars(char[] chars);
*
* String newStringFromBytes(byte[] bytes, String charsetName)
* throws UnsupportedEncodingException;
* }
* </pre>
*
* Here's an example of it being used:
*
* <pre>
* StringFactory sf = QuickConstructorGenerator.getInstance(String.class, StringFactory.class);
* ...
* String str = sf.newStringFromChars(new char[] {'h', 'e', 'l', 'l', 'o'});
* </pre>
*
* @param objectType type of object to construct
* @param factory interface defining which objects can be constructed
* @throws IllegalArgumentException if factory type is not an interface or
* if it is malformed
*/
@SuppressWarnings("unchecked")
public static synchronized <F> F getInstance(Class<?> objectType, Class<F> factory) {
try {
return org.cojen.util.QuickConstructorGenerator.getInstance(objectType, factory);
} catch (NoClassDefFoundError e) {
// Use older code instead.
}
SoftValuedCache<Class<?>, Object> innerCache = cCache.get(factory);
if (innerCache == null) {
innerCache = SoftValuedCache.newCache(7);
cCache.put(factory, innerCache);
}
F instance = (F) innerCache.get(objectType);
if (instance != null) {
return instance;
}
if (objectType == null) {
throw new IllegalArgumentException("No object type");
}
if (factory == null) {
throw new IllegalArgumentException("No factory type");
}
if (!factory.isInterface()) {
throw new IllegalArgumentException("Factory must be an interface");
}
String prefix = objectType.getName();
if (prefix.startsWith("java.")) {
// Defining classes in java packages is restricted.
int index = prefix.lastIndexOf('.');
if (index > 0) {
prefix = prefix.substring(index + 1);
}
}
ClassInjector ci = ClassInjector.create(prefix, objectType.getClassLoader());
ClassFile cf = null;
for (Method method : factory.getMethods()) {
if (!Modifier.isAbstract(method.getModifiers())) {
continue;
}
Constructor ctor;
try {
ctor = objectType.getConstructor((Class[]) method.getParameterTypes());
} catch (NoSuchMethodException e) {
throw new IllegalArgumentException(e);
}
if (!method.getReturnType().isAssignableFrom(objectType)) {
throw new IllegalArgumentException
("Method return type must be \"" +
objectType.getName() + "\" or supertype: " + method);
}
Class<?>[] methodExTypes = method.getExceptionTypes();
for (Class<?> ctorExType : ctor.getExceptionTypes()) {
if (RuntimeException.class.isAssignableFrom(ctorExType) ||
Error.class.isAssignableFrom(ctorExType)) {
continue;
}
exCheck: {
// Make sure method declares throwing it or a supertype.
for (Class<?> methodExType : methodExTypes) {
if (methodExType.isAssignableFrom(ctorExType)) {
break exCheck;
}
}
throw new IllegalArgumentException("Method must declare throwing \"" +
ctorExType.getName() +"\": " + method);
}
}
if (cf == null) {
cf = new ClassFile(ci.getClassName());
cf.setSourceFile(QuickConstructorGenerator.class.getName());
cf.setTarget("1.5");
cf.addInterface(factory);
cf.markSynthetic();
cf.addDefaultConstructor();
}
// Now define the method that constructs the object.
CodeBuilder b = new CodeBuilder(cf.addMethod(method));
b.newObject(TypeDesc.forClass(objectType));
b.dup();
int count = b.getParameterCount();
for (int i=0; i<count; i++) {
b.loadLocal(b.getParameter(i));
}
b.invoke(ctor);
b.returnValue(TypeDesc.OBJECT);
}
if (cf == null) {
// No methods found to implement.
throw new IllegalArgumentException("No methods in factory to implement");
}
try {
instance = (F) ci.defineClass(cf).newInstance();
} catch (IllegalAccessException e) {
throw new UndeclaredThrowableException(e);
} catch (InstantiationException e) {
throw new UndeclaredThrowableException(e);
}
innerCache.put(objectType, instance);
return instance;
}
}
|
