1 /*
2 * Copyright (c) 2012, 2019, 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.io.InvalidObjectException;
29 import java.io.ObjectStreamException;
30 import java.lang.reflect.Method;
31 import java.security.AccessController;
32 import java.security.PrivilegedActionException;
33 import java.security.PrivilegedExceptionAction;
34 import java.util.Objects;
35
36 /**
37 * Serialized form of a lambda expression. The properties of this class
38 * represent the information that is present at the lambda factory site, including
39 * static metafactory arguments such as the identity of the primary functional
40 * interface method and the identity of the implementation method, as well as
41 * dynamic metafactory arguments such as values captured from the lexical scope
42 * at the time of lambda capture.
43 *
44 * <p>Implementors of serializable lambdas, such as compilers or language
45 * runtime libraries, are expected to ensure that instances deserialize properly.
46 * One means to do so is to ensure that the {@code writeReplace} method returns
47 * an instance of {@code SerializedLambda}, rather than allowing default
48 * serialization to proceed.
49 *
50 * <p>{@code SerializedLambda} has a {@code readResolve} method that looks for
51 * a (possibly private) static method called
52 * {@code $deserializeLambda$(SerializedLambda)} in the capturing class, invokes
53 * that with itself as the first argument, and returns the result. Lambda classes
54 * implementing {@code $deserializeLambda$} are responsible for validating
55 * that the properties of the {@code SerializedLambda} are consistent with a
56 * lambda actually captured by that class.
57 *
58 * <p>The identity of a function object produced by deserializing the serialized
59 * form is unpredictable, and therefore identity-sensitive operations (such as
60 * reference equality, object locking, and {@code System.identityHashCode()} may
61 * produce different results in different implementations, or even upon
62 * different deserializations in the same implementation.
63 *
64 * @see LambdaMetafactory
65 * @since 1.8
66 */
67 public final class SerializedLambda implements Serializable {
68 @java.io.Serial
69 private static final long serialVersionUID = 8025925345765570181L;
70 private final Class<?> capturingClass;
71 private final String functionalInterfaceClass;
72 private final String functionalInterfaceMethodName;
73 private final String functionalInterfaceMethodSignature;
74 private final String implClass;
75 private final String implMethodName;
76 private final String implMethodSignature;
77 private final int implMethodKind;
78 private final String instantiatedMethodType;
79 private final Object[] capturedArgs;
80
81 /**
82 * Create a {@code SerializedLambda} from the low-level information present
83 * at the lambda factory site.
84 *
85 * @param capturingClass The class in which the lambda expression appears
86 * @param functionalInterfaceClass Name, in slash-delimited form, of static
87 * type of the returned lambda object
88 * @param functionalInterfaceMethodName Name of the functional interface
89 * method for the present at the
90 * lambda factory site
91 * @param functionalInterfaceMethodSignature Signature of the functional
92 * interface method present at
93 * the lambda factory site
94 * @param implMethodKind Method handle kind for the implementation method
95 * @param implClass Name, in slash-delimited form, for the class holding
96 * the implementation method
97 * @param implMethodName Name of the implementation method
98 * @param implMethodSignature Signature of the implementation method
99 * @param instantiatedMethodType The signature of the primary functional
100 * interface method after type variables
101 * are substituted with their instantiation
102 * from the capture site
103 * @param capturedArgs The dynamic arguments to the lambda factory site,
104 * which represent variables captured by
105 * the lambda
106 */
107 public SerializedLambda(Class<?> capturingClass,
108 String functionalInterfaceClass,
109 String functionalInterfaceMethodName,
110 String functionalInterfaceMethodSignature,
111 int implMethodKind,
112 String implClass,
113 String implMethodName,
114 String implMethodSignature,
115 String instantiatedMethodType,
116 Object[] capturedArgs) {
117 this.capturingClass = capturingClass;
118 this.functionalInterfaceClass = functionalInterfaceClass;
119 this.functionalInterfaceMethodName = functionalInterfaceMethodName;
120 this.functionalInterfaceMethodSignature = functionalInterfaceMethodSignature;
121 this.implMethodKind = implMethodKind;
122 this.implClass = implClass;
123 this.implMethodName = implMethodName;
124 this.implMethodSignature = implMethodSignature;
125 this.instantiatedMethodType = instantiatedMethodType;
126 this.capturedArgs = Objects.requireNonNull(capturedArgs).clone();
127 }
128
129 /**
130 * Get the name of the class that captured this lambda.
131 * @return the name of the class that captured this lambda
132 */
133 public String getCapturingClass() {
134 return capturingClass.getName().replace('.', '/');
135 }
136
137 /**
138 * Get the name of the invoked type to which this
139 * lambda has been converted
140 * @return the name of the functional interface class to which
141 * this lambda has been converted
142 */
143 public String getFunctionalInterfaceClass() {
144 return functionalInterfaceClass;
145 }
146
147 /**
148 * Get the name of the primary method for the functional interface
149 * to which this lambda has been converted.
150 * @return the name of the primary methods of the functional interface
151 */
152 public String getFunctionalInterfaceMethodName() {
153 return functionalInterfaceMethodName;
154 }
155
156 /**
157 * Get the signature of the primary method for the functional
158 * interface to which this lambda has been converted.
159 * @return the signature of the primary method of the functional
160 * interface
161 */
162 public String getFunctionalInterfaceMethodSignature() {
163 return functionalInterfaceMethodSignature;
164 }
165
166 /**
167 * Get the name of the class containing the implementation
168 * method.
169 * @return the name of the class containing the implementation
170 * method
171 */
172 public String getImplClass() {
173 return implClass;
174 }
175
176 /**
177 * Get the name of the implementation method.
178 * @return the name of the implementation method
179 */
180 public String getImplMethodName() {
181 return implMethodName;
182 }
183
184 /**
185 * Get the signature of the implementation method.
186 * @return the signature of the implementation method
187 */
188 public String getImplMethodSignature() {
189 return implMethodSignature;
190 }
191
192 /**
193 * Get the method handle kind (see {@link MethodHandleInfo}) of
194 * the implementation method.
195 * @return the method handle kind of the implementation method
196 */
197 public int getImplMethodKind() {
198 return implMethodKind;
199 }
200
201 /**
202 * Get the signature of the primary functional interface method
203 * after type variables are substituted with their instantiation
204 * from the capture site.
205 * @return the signature of the primary functional interface method
206 * after type variable processing
207 */
208 public final String getInstantiatedMethodType() {
209 return instantiatedMethodType;
210 }
211
212 /**
213 * Get the count of dynamic arguments to the lambda capture site.
214 * @return the count of dynamic arguments to the lambda capture site
215 */
216 public int getCapturedArgCount() {
217 return capturedArgs.length;
218 }
219
220 /**
221 * Get a dynamic argument to the lambda capture site.
222 * @param i the argument to capture
223 * @return a dynamic argument to the lambda capture site
224 */
225 public Object getCapturedArg(int i) {
226 return capturedArgs[i];
227 }
228
229 @java.io.Serial
230 private Object readResolve() throws ObjectStreamException {
231 try {
232 Method deserialize = AccessController.doPrivileged(new PrivilegedExceptionAction<>() {
233 @Override
234 public Method run() throws Exception {
235 Method m = capturingClass.getDeclaredMethod("$deserializeLambda$", SerializedLambda.class);
236 m.setAccessible(true);
237 return m;
238 }
239 });
240
241 return deserialize.invoke(null, this);
242 } catch (ReflectiveOperationException roe) {
243 ObjectStreamException ose = new InvalidObjectException("ReflectiveOperationException during deserialization");
244 ose.initCause(roe);
245 throw ose;
246 } catch (PrivilegedActionException e) {
247 Exception cause = e.getException();
248 if (cause instanceof RuntimeException)
249 throw (RuntimeException) cause;
250 else
251 throw new RuntimeException("Exception in SerializedLambda.readResolve", e);
252 }
253 }
254
255 @Override
256 public String toString() {
257 String implKind=MethodHandleInfo.referenceKindToString(implMethodKind);
258 return String.format("SerializedLambda[%s=%s, %s=%s.%s:%s, " +
259 "%s=%s %s.%s:%s, %s=%s, %s=%d]",
260 "capturingClass", capturingClass,
261 "functionalInterfaceMethod", functionalInterfaceClass,
262 functionalInterfaceMethodName,
263 functionalInterfaceMethodSignature,
264 "implementation",
265 implKind,
266 implClass, implMethodName, implMethodSignature,
267 "instantiatedMethodType", instantiatedMethodType,
268 "numCaptured", capturedArgs.length);
269 }
270 }