1 /*
2 * Copyright (c) 2012, 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 package java.lang.invoke;
26
27 import java.io.Serializable;
28 import java.lang.reflect.Method;
29 import java.security.AccessController;
30 import java.security.PrivilegedActionException;
31 import java.security.PrivilegedExceptionAction;
32 import java.util.Objects;
33
34 /**
35 * Serialized form of a lambda expression. The properties of this class
36 * represent the information that is present at the lambda factory site, including
37 * static metafactory arguments such as the identity of the primary functional
38 * interface method and the identity of the implementation method, as well as
39 * dynamic metafactory arguments such as values captured from the lexical scope
40 * at the time of lambda capture.
41 *
42 * <p>Implementors of serializable lambdas, such as compilers or language
43 * runtime libraries, are expected to ensure that instances deserialize properly.
44 * One means to do so is to ensure that the {@code writeReplace} method returns
45 * an instance of {@code SerializedLambda}, rather than allowing default
46 * serialization to proceed.
47 *
48 * <p>{@code SerializedLambda} has a {@code readResolve} method that looks for
49 * a (possibly private) static method called
50 * {@code $deserializeLambda$(SerializedLambda)} in the capturing class, invokes
51 * that with itself as the first argument, and returns the result. Lambda classes
52 * implementing {@code $deserializeLambda$} are responsible for validating
53 * that the properties of the {@code SerializedLambda} are consistent with a
54 * lambda actually captured by that class.
55 *
56 * @see LambdaMetafactory
57 */
58 public final class SerializedLambda implements Serializable {
59 private static final long serialVersionUID = 8025925345765570181L;
60 private final Class<?> capturingClass;
61 private final String functionalInterfaceClass;
62 private final String functionalInterfaceMethodName;
63 private final String functionalInterfaceMethodSignature;
64 private final String implClass;
65 private final String implMethodName;
66 private final String implMethodSignature;
67 private final int implMethodKind;
68 private final String instantiatedMethodType;
69 private final Object[] capturedArgs;
70
71 /**
72 * Create a {@code SerializedLambda} from the low-level information present
73 * at the lambda factory site.
74 *
75 * @param capturingClass The class in which the lambda expression appears
76 * @param functionalInterfaceClass Name, in slash-delimited form, of static
77 * type of the returned lambda object
78 * @param functionalInterfaceMethodName Name of the functional interface
79 * method for the present at the
80 * lambda factory site
81 * @param functionalInterfaceMethodSignature Signature of the functional
82 * interface method present at
83 * the lambda factory site
84 * @param implMethodKind Method handle kind for the implementation method
85 * @param implClass Name, in slash-delimited form, for the class holding
86 * the implementation method
87 * @param implMethodName Name of the implementation method
88 * @param implMethodSignature Signature of the implementation method
89 * @param instantiatedMethodType The signature of the primary functional
90 * interface method after type variables
91 * are substituted with their instantiation
92 * from the capture site
93 * @param capturedArgs The dynamic arguments to the lambda factory site,
94 * which represent variables captured by
95 * the lambda
96 */
97 public SerializedLambda(Class<?> capturingClass,
98 String functionalInterfaceClass,
99 String functionalInterfaceMethodName,
100 String functionalInterfaceMethodSignature,
101 int implMethodKind,
102 String implClass,
103 String implMethodName,
104 String implMethodSignature,
105 String instantiatedMethodType,
106 Object[] capturedArgs) {
107 this.capturingClass = capturingClass;
108 this.functionalInterfaceClass = functionalInterfaceClass;
109 this.functionalInterfaceMethodName = functionalInterfaceMethodName;
110 this.functionalInterfaceMethodSignature = functionalInterfaceMethodSignature;
111 this.implMethodKind = implMethodKind;
112 this.implClass = implClass;
113 this.implMethodName = implMethodName;
114 this.implMethodSignature = implMethodSignature;
115 this.instantiatedMethodType = instantiatedMethodType;
116 this.capturedArgs = Objects.requireNonNull(capturedArgs).clone();
117 }
118
119 /**
120 * Get the name of the class that captured this lambda.
121 * @return the name of the class that captured this lambda
122 */
123 public String getCapturingClass() {
124 return capturingClass.getName().replace('.', '/');
125 }
126
127 /**
128 * Get the name of the invoked type to which this
129 * lambda has been converted
130 * @return the name of the functional interface class to which
131 * this lambda has been converted
132 */
133 public String getFunctionalInterfaceClass() {
134 return functionalInterfaceClass;
135 }
136
137 /**
138 * Get the name of the primary method for the functional interface
139 * to which this lambda has been converted.
140 * @return the name of the primary methods of the functional interface
141 */
142 public String getFunctionalInterfaceMethodName() {
143 return functionalInterfaceMethodName;
144 }
145
146 /**
147 * Get the signature of the primary method for the functional
148 * interface to which this lambda has been converted.
149 * @return the signature of the primary method of the functional
150 * interface
151 */
152 public String getFunctionalInterfaceMethodSignature() {
153 return functionalInterfaceMethodSignature;
154 }
155
156 /**
157 * Get the name of the class containing the implementation
158 * method.
159 * @return the name of the class containing the implementation
160 * method
161 */
162 public String getImplClass() {
163 return implClass;
164 }
165
166 /**
167 * Get the name of the implementation method.
168 * @return the name of the implementation method
169 */
170 public String getImplMethodName() {
171 return implMethodName;
172 }
173
174 /**
175 * Get the signature of the implementation method.
176 * @return the signature of the implementation method
177 */
178 public String getImplMethodSignature() {
179 return implMethodSignature;
180 }
181
182 /**
183 * Get the method handle kind (see {@link MethodHandleInfo}) of
184 * the implementation method.
185 * @return the method handle kind of the implementation method
186 */
187 public int getImplMethodKind() {
188 return implMethodKind;
189 }
190
191 /**
192 * Get the signature of the primary functional interface method
193 * after type variables are substituted with their instantiation
194 * from the capture site.
195 * @return the signature of the primary functional interface method
196 * after type variable processing
197 */
198 public final String getInstantiatedMethodType() {
199 return instantiatedMethodType;
200 }
201
202 /**
203 * Get the count of dynamic arguments to the lambda capture site.
204 * @return the count of dynamic arguments to the lambda capture site
205 */
206 public int getCapturedArgCount() {
207 return capturedArgs.length;
208 }
209
210 /**
211 * Get a dynamic argument to the lambda capture site.
212 * @param i the argument to capture
213 * @return a dynamic argument to the lambda capture site
214 */
215 public Object getCapturedArg(int i) {
216 return capturedArgs[i];
217 }
218
219 private Object readResolve() throws ReflectiveOperationException {
220 try {
221 Method deserialize = AccessController.doPrivileged(new PrivilegedExceptionAction<>() {
222 @Override
223 public Method run() throws Exception {
224 Method m = capturingClass.getDeclaredMethod("$deserializeLambda$", SerializedLambda.class);
225 m.setAccessible(true);
226 return m;
227 }
228 });
229
230 return deserialize.invoke(null, this);
231 }
232 catch (PrivilegedActionException e) {
233 Exception cause = e.getException();
234 if (cause instanceof ReflectiveOperationException)
235 throw (ReflectiveOperationException) cause;
236 else if (cause instanceof RuntimeException)
237 throw (RuntimeException) cause;
238 else
239 throw new RuntimeException("Exception in SerializedLambda.readResolve", e);
240 }
241 }
242
243 @Override
244 public String toString() {
245 String implKind=MethodHandleInfo.referenceKindToString(implMethodKind);
246 return String.format("SerializedLambda[%s=%s, %s=%s.%s:%s, " +
247 "%s=%s %s.%s:%s, %s=%s, %s=%d]",
248 "capturingClass", capturingClass,
249 "functionalInterfaceMethod", functionalInterfaceClass,
250 functionalInterfaceMethodName,
251 functionalInterfaceMethodSignature,
252 "implementation",
253 implKind,
254 implClass, implMethodName, implMethodSignature,
255 "instantiatedMethodType", instantiatedMethodType,
256 "numCaptured", capturedArgs.length);
257 }
258 }