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 @SuppressWarnings("serial") // Not statically typed as Serializable
80 private final Object[] capturedArgs;
81
82 /**
83 * Create a {@code SerializedLambda} from the low-level information present
84 * at the lambda factory site.
85 *
86 * @param capturingClass The class in which the lambda expression appears
87 * @param functionalInterfaceClass Name, in slash-delimited form, of static
88 * type of the returned lambda object
89 * @param functionalInterfaceMethodName Name of the functional interface
90 * method for the present at the
91 * lambda factory site
92 * @param functionalInterfaceMethodSignature Signature of the functional
93 * interface method present at
94 * the lambda factory site
95 * @param implMethodKind Method handle kind for the implementation method
96 * @param implClass Name, in slash-delimited form, for the class holding
97 * the implementation method
98 * @param implMethodName Name of the implementation method
99 * @param implMethodSignature Signature of the implementation method
100 * @param instantiatedMethodType The signature of the primary functional
101 * interface method after type variables
102 * are substituted with their instantiation
103 * from the capture site
104 * @param capturedArgs The dynamic arguments to the lambda factory site,
105 * which represent variables captured by
106 * the lambda
107 */
108 public SerializedLambda(Class<?> capturingClass,
109 String functionalInterfaceClass,
110 String functionalInterfaceMethodName,
111 String functionalInterfaceMethodSignature,
112 int implMethodKind,
113 String implClass,
114 String implMethodName,
115 String implMethodSignature,
116 String instantiatedMethodType,
117 Object[] capturedArgs) {
118 this.capturingClass = capturingClass;
119 this.functionalInterfaceClass = functionalInterfaceClass;
120 this.functionalInterfaceMethodName = functionalInterfaceMethodName;
121 this.functionalInterfaceMethodSignature = functionalInterfaceMethodSignature;
122 this.implMethodKind = implMethodKind;
123 this.implClass = implClass;
124 this.implMethodName = implMethodName;
125 this.implMethodSignature = implMethodSignature;
126 this.instantiatedMethodType = instantiatedMethodType;
127 this.capturedArgs = Objects.requireNonNull(capturedArgs).clone();
128 }
129
130 /**
131 * Get the name of the class that captured this lambda.
132 * @return the name of the class that captured this lambda
133 */
134 public String getCapturingClass() {
135 return capturingClass.getName().replace('.', '/');
136 }
137
138 /**
139 * Get the name of the invoked type to which this
140 * lambda has been converted
141 * @return the name of the functional interface class to which
142 * this lambda has been converted
143 */
144 public String getFunctionalInterfaceClass() {
145 return functionalInterfaceClass;
146 }
147
148 /**
149 * Get the name of the primary method for the functional interface
150 * to which this lambda has been converted.
151 * @return the name of the primary methods of the functional interface
152 */
153 public String getFunctionalInterfaceMethodName() {
154 return functionalInterfaceMethodName;
155 }
156
157 /**
158 * Get the signature of the primary method for the functional
159 * interface to which this lambda has been converted.
160 * @return the signature of the primary method of the functional
161 * interface
162 */
163 public String getFunctionalInterfaceMethodSignature() {
164 return functionalInterfaceMethodSignature;
165 }
166
167 /**
168 * Get the name of the class containing the implementation
169 * method.
170 * @return the name of the class containing the implementation
171 * method
172 */
173 public String getImplClass() {
174 return implClass;
175 }
176
177 /**
178 * Get the name of the implementation method.
179 * @return the name of the implementation method
180 */
181 public String getImplMethodName() {
182 return implMethodName;
183 }
184
185 /**
186 * Get the signature of the implementation method.
187 * @return the signature of the implementation method
188 */
189 public String getImplMethodSignature() {
190 return implMethodSignature;
191 }
192
193 /**
194 * Get the method handle kind (see {@link MethodHandleInfo}) of
195 * the implementation method.
196 * @return the method handle kind of the implementation method
197 */
198 public int getImplMethodKind() {
199 return implMethodKind;
200 }
201
202 /**
203 * Get the signature of the primary functional interface method
204 * after type variables are substituted with their instantiation
205 * from the capture site.
206 * @return the signature of the primary functional interface method
207 * after type variable processing
208 */
209 public final String getInstantiatedMethodType() {
210 return instantiatedMethodType;
211 }
212
213 /**
214 * Get the count of dynamic arguments to the lambda capture site.
215 * @return the count of dynamic arguments to the lambda capture site
216 */
217 public int getCapturedArgCount() {
218 return capturedArgs.length;
219 }
220
221 /**
222 * Get a dynamic argument to the lambda capture site.
223 * @param i the argument to capture
224 * @return a dynamic argument to the lambda capture site
225 */
226 public Object getCapturedArg(int i) {
227 return capturedArgs[i];
228 }
229
230 @java.io.Serial
231 private Object readResolve() throws ObjectStreamException {
232 try {
233 Method deserialize = AccessController.doPrivileged(new PrivilegedExceptionAction<>() {
234 @Override
235 public Method run() throws Exception {
236 Method m = capturingClass.getDeclaredMethod("$deserializeLambda$", SerializedLambda.class);
237 m.setAccessible(true);
238 return m;
239 }
240 });
241
242 return deserialize.invoke(null, this);
243 } catch (ReflectiveOperationException roe) {
244 ObjectStreamException ose = new InvalidObjectException("ReflectiveOperationException during deserialization");
245 ose.initCause(roe);
246 throw ose;
247 } catch (PrivilegedActionException e) {
248 Exception cause = e.getException();
249 if (cause instanceof RuntimeException)
250 throw (RuntimeException) cause;
251 else
252 throw new RuntimeException("Exception in SerializedLambda.readResolve", e);
253 }
254 }
255
256 @Override
257 public String toString() {
258 String implKind=MethodHandleInfo.referenceKindToString(implMethodKind);
259 return String.format("SerializedLambda[%s=%s, %s=%s.%s:%s, " +
260 "%s=%s %s.%s:%s, %s=%s, %s=%d]",
261 "capturingClass", capturingClass,
262 "functionalInterfaceMethod", functionalInterfaceClass,
263 functionalInterfaceMethodName,
264 functionalInterfaceMethodSignature,
265 "implementation",
266 implKind,
267 implClass, implMethodName, implMethodSignature,
268 "instantiatedMethodType", instantiatedMethodType,
269 "numCaptured", capturedArgs.length);
270 }
271 }