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.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 private static final long serialVersionUID = 8025925345765570181L;
69 private final Class<?> capturingClass;
70 private final String functionalInterfaceClass;
71 private final String functionalInterfaceMethodName;
72 private final String functionalInterfaceMethodSignature;
73 private final String implClass;
74 private final String implMethodName;
75 private final String implMethodSignature;
76 private final int implMethodKind;
77 private final String instantiatedMethodType;
78 private final Object[] capturedArgs;
79
80 /**
81 * Create a {@code SerializedLambda} from the low-level information present
82 * at the lambda factory site.
83 *
84 * @param capturingClass The class in which the lambda expression appears
85 * @param functionalInterfaceClass Name, in slash-delimited form, of static
86 * type of the returned lambda object
87 * @param functionalInterfaceMethodName Name of the functional interface
88 * method for the present at the
89 * lambda factory site
90 * @param functionalInterfaceMethodSignature Signature of the functional
91 * interface method present at
92 * the lambda factory site
93 * @param implMethodKind Method handle kind for the implementation method
94 * @param implClass Name, in slash-delimited form, for the class holding
95 * the implementation method
96 * @param implMethodName Name of the implementation method
97 * @param implMethodSignature Signature of the implementation method
98 * @param instantiatedMethodType The signature of the primary functional
99 * interface method after type variables
100 * are substituted with their instantiation
101 * from the capture site
102 * @param capturedArgs The dynamic arguments to the lambda factory site,
103 * which represent variables captured by
104 * the lambda
105 */
106 public SerializedLambda(Class<?> capturingClass,
107 String functionalInterfaceClass,
108 String functionalInterfaceMethodName,
109 String functionalInterfaceMethodSignature,
110 int implMethodKind,
111 String implClass,
112 String implMethodName,
113 String implMethodSignature,
114 String instantiatedMethodType,
115 Object[] capturedArgs) {
116 this.capturingClass = capturingClass;
117 this.functionalInterfaceClass = functionalInterfaceClass;
118 this.functionalInterfaceMethodName = functionalInterfaceMethodName;
119 this.functionalInterfaceMethodSignature = functionalInterfaceMethodSignature;
120 this.implMethodKind = implMethodKind;
121 this.implClass = implClass;
122 this.implMethodName = implMethodName;
123 this.implMethodSignature = implMethodSignature;
124 this.instantiatedMethodType = instantiatedMethodType;
125 this.capturedArgs = Objects.requireNonNull(capturedArgs).clone();
126 }
127
128 /**
129 * Get the name of the class that captured this lambda.
130 * @return the name of the class that captured this lambda
131 */
132 public String getCapturingClass() {
133 return capturingClass.getName().replace('.', '/');
134 }
135
136 /**
137 * Get the name of the invoked type to which this
138 * lambda has been converted
139 * @return the name of the functional interface class to which
140 * this lambda has been converted
141 */
142 public String getFunctionalInterfaceClass() {
143 return functionalInterfaceClass;
144 }
145
146 /**
147 * Get the name of the primary method for the functional interface
148 * to which this lambda has been converted.
149 * @return the name of the primary methods of the functional interface
150 */
151 public String getFunctionalInterfaceMethodName() {
152 return functionalInterfaceMethodName;
153 }
154
155 /**
156 * Get the signature of the primary method for the functional
157 * interface to which this lambda has been converted.
158 * @return the signature of the primary method of the functional
159 * interface
160 */
161 public String getFunctionalInterfaceMethodSignature() {
162 return functionalInterfaceMethodSignature;
163 }
164
165 /**
166 * Get the name of the class containing the implementation
167 * method.
168 * @return the name of the class containing the implementation
169 * method
170 */
171 public String getImplClass() {
172 return implClass;
173 }
174
175 /**
176 * Get the name of the implementation method.
177 * @return the name of the implementation method
178 */
179 public String getImplMethodName() {
180 return implMethodName;
181 }
182
183 /**
184 * Get the signature of the implementation method.
185 * @return the signature of the implementation method
186 */
187 public String getImplMethodSignature() {
188 return implMethodSignature;
189 }
190
191 /**
192 * Get the method handle kind (see {@link MethodHandleInfo}) of
193 * the implementation method.
194 * @return the method handle kind of the implementation method
195 */
196 public int getImplMethodKind() {
197 return implMethodKind;
198 }
199
200 /**
201 * Get the signature of the primary functional interface method
202 * after type variables are substituted with their instantiation
203 * from the capture site.
204 * @return the signature of the primary functional interface method
205 * after type variable processing
206 */
207 public final String getInstantiatedMethodType() {
208 return instantiatedMethodType;
209 }
210
211 /**
212 * Get the count of dynamic arguments to the lambda capture site.
213 * @return the count of dynamic arguments to the lambda capture site
214 */
215 public int getCapturedArgCount() {
216 return capturedArgs.length;
217 }
218
219 /**
220 * Get a dynamic argument to the lambda capture site.
221 * @param i the argument to capture
222 * @return a dynamic argument to the lambda capture site
223 */
224 public Object getCapturedArg(int i) {
225 return capturedArgs[i];
226 }
227
228 private Object readResolve() throws ObjectStreamException {
229 try {
230 Method deserialize = AccessController.doPrivileged(new PrivilegedExceptionAction<>() {
231 @Override
232 public Method run() throws Exception {
233 Method m = capturingClass.getDeclaredMethod("$deserializeLambda$", SerializedLambda.class);
234 m.setAccessible(true);
235 return m;
236 }
237 });
238
239 return deserialize.invoke(null, this);
240 } catch (ReflectiveOperationException roe) {
241 ObjectStreamException ose = new InvalidObjectException("ReflectiveOperationException during deserialization");
242 ose.initCause(roe);
243 throw ose;
244 } catch (PrivilegedActionException e) {
245 Exception cause = e.getException();
246 if (cause instanceof RuntimeException)
247 throw (RuntimeException) cause;
248 else
249 throw new RuntimeException("Exception in SerializedLambda.readResolve", e);
250 }
251 }
252
253 @Override
254 public String toString() {
255 String implKind=MethodHandleInfo.referenceKindToString(implMethodKind);
256 return String.format("SerializedLambda[%s=%s, %s=%s.%s:%s, " +
257 "%s=%s %s.%s:%s, %s=%s, %s=%d]",
258 "capturingClass", capturingClass,
259 "functionalInterfaceMethod", functionalInterfaceClass,
260 functionalInterfaceMethodName,
261 functionalInterfaceMethodSignature,
262 "implementation",
263 implKind,
264 implClass, implMethodName, implMethodSignature,
265 "instantiatedMethodType", instantiatedMethodType,
266 "numCaptured", capturedArgs.length);
267 }
268 }