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 * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

package java.lang.invoke;

import java.io.Serializable;

import java.lang.reflect.Method;

import java.security.AccessController;

import java.security.PrivilegedActionException;

import java.security.PrivilegedExceptionAction;

import java.util.Objects;

/**

 * Serialized form of a lambda expression.  The properties of this class

 * represent the information that is present at the lambda factory site, including

 * static metafactory arguments such as the identity of the primary functional

 * interface method and the identity of the implementation method, as well as

 * dynamic metafactory arguments such as values captured from the lexical scope

 * at the time of lambda capture.

 *

 * <p>Implementors of serializable lambdas, such as compilers or language

 * runtime libraries, are expected to ensure that instances deserialize properly.

 * One means to do so is to ensure that the {@code writeReplace} method returns

 * an instance of {@code SerializedLambda}, rather than allowing default

 * serialization to proceed.

 *

 * <p>{@code SerializedLambda} has a {@code readResolve} method that looks for

 * a (possibly private) static method called

 * {@code $deserializeLambda$(SerializedLambda)} in the capturing class, invokes

 * that with itself as the first argument, and returns the result.  Lambda classes

 * implementing {@code $deserializeLambda$} are responsible for validating

 * that the properties of the {@code SerializedLambda} are consistent with a

 * lambda actually captured by that class.

 *

 * @see LambdaMetafactory

 */

public final class SerializedLambda implements Serializable {

    private static final long serialVersionUID = 8025925345765570181L;

    private final Class<?> capturingClass;

    private final String functionalInterfaceClass;

    private final String functionalInterfaceMethodName;

    private final String functionalInterfaceMethodSignature;

    private final String implClass;

    private final String implMethodName;

    private final String implMethodSignature;

    private final int implMethodKind;

    private final String instantiatedMethodType;

    private final Object[] capturedArgs;

    /**

     * Create a {@code SerializedLambda} from the low-level information present

     * at the lambda factory site.

     *

     * @param capturingClass The class in which the lambda expression appears

     * @param functionalInterfaceClass Name, in slash-delimited form, of static

     *                                 type of the returned lambda object

     * @param functionalInterfaceMethodName Name of the functional interface

     *                                      method for the present at the

     *                                      lambda factory site

     * @param functionalInterfaceMethodSignature Signature of the functional

     *                                           interface method present at

     *                                           the lambda factory site

     * @param implMethodKind Method handle kind for the implementation method

     * @param implClass Name, in slash-delimited form, for the class holding

     *                  the implementation method

     * @param implMethodName Name of the implementation method

     * @param implMethodSignature Signature of the implementation method

     * @param instantiatedMethodType The signature of the primary functional

     *                               interface method after type variables

     *                               are substituted with their instantiation

     *                               from the capture site

     * @param capturedArgs The dynamic arguments to the lambda factory site,

     *                     which represent variables captured by

     *                     the lambda

     */

    public SerializedLambda(Class<?> capturingClass,

                            String functionalInterfaceClass,

                            String functionalInterfaceMethodName,

                            String functionalInterfaceMethodSignature,

                            int implMethodKind,

                            String implClass,

                            String implMethodName,

                            String implMethodSignature,

                            String instantiatedMethodType,

                            Object[] capturedArgs) {

        this.capturingClass = capturingClass;

        this.functionalInterfaceClass = functionalInterfaceClass;

        this.functionalInterfaceMethodName = functionalInterfaceMethodName;

        this.functionalInterfaceMethodSignature = functionalInterfaceMethodSignature;

        this.implMethodKind = implMethodKind;

        this.implClass = implClass;

        this.implMethodName = implMethodName;

        this.implMethodSignature = implMethodSignature;

        this.instantiatedMethodType = instantiatedMethodType;

        this.capturedArgs = Objects.requireNonNull(capturedArgs).clone();

    }

    /**

     * Get the name of the class that captured this lambda.

     * @return the name of the class that captured this lambda

     */

    public String getCapturingClass() {

        return capturingClass.getName().replace('.', '/');

    }

    /**

     * Get the name of the invoked type to which this

     * lambda has been converted

     * @return the name of the functional interface class to which

     * this lambda has been converted

     */

    public String getFunctionalInterfaceClass() {

        return functionalInterfaceClass;

    }

    /**

     * Get the name of the primary method for the functional interface

     * to which this lambda has been converted.

     * @return the name of the primary methods of the functional interface

     */

    public String getFunctionalInterfaceMethodName() {

        return functionalInterfaceMethodName;

    }

    /**

     * Get the signature of the primary method for the functional

     * interface to which this lambda has been converted.

     * @return the signature of the primary method of the functional

     * interface

     */

    public String getFunctionalInterfaceMethodSignature() {

        return functionalInterfaceMethodSignature;

    }

    /**

     * Get the name of the class containing the implementation

     * method.

     * @return the name of the class containing the implementation

     * method

     */

    public String getImplClass() {

        return implClass;

    }

    /**

     * Get the name of the implementation method.

     * @return the name of the implementation method

     */

    public String getImplMethodName() {

        return implMethodName;

    }

    /**

     * Get the signature of the implementation method.

     * @return the signature of the implementation method

     */

    public String getImplMethodSignature() {

        return implMethodSignature;

    }

    /**

     * Get the method handle kind (see {@link MethodHandleInfo}) of

     * the implementation method.

     * @return the method handle kind of the implementation method

     */

    public int getImplMethodKind() {

        return implMethodKind;

    }

    /**

     * Get the signature of the primary functional interface method

     * after type variables are substituted with their instantiation

     * from the capture site.

     * @return the signature of the primary functional interface method

     * after type variable processing

     */

    public final String getInstantiatedMethodType() {

        return instantiatedMethodType;

    }

    /**

     * Get the count of dynamic arguments to the lambda capture site.

     * @return the count of dynamic arguments to the lambda capture site

     */

    public int getCapturedArgCount() {

        return capturedArgs.length;

    }

    /**

     * Get a dynamic argument to the lambda capture site.

     * @param i the argument to capture

     * @return a dynamic argument to the lambda capture site

     */

    public Object getCapturedArg(int i) {

        return capturedArgs[i];

    }

    private Object readResolve() throws ReflectiveOperationException {

        try {

            Method deserialize = AccessController.doPrivileged(new PrivilegedExceptionAction<Method>() {

                @Override

                public Method run() throws Exception {

                    Method m = capturingClass.getDeclaredMethod("$deserializeLambda$", SerializedLambda.class);

                    m.setAccessible(true);

                    return m;

                }

            });

            return deserialize.invoke(null, this);

        }

        catch (PrivilegedActionException e) {

            Exception cause = e.getException();

            if (cause instanceof ReflectiveOperationException)

                throw (ReflectiveOperationException) cause;

            else if (cause instanceof RuntimeException)

                throw (RuntimeException) cause;

            else

                throw new RuntimeException("Exception in SerializedLambda.readResolve", e);

        }

    }

    @Override

    public String toString() {

        return String.format("SerializedLambda[%s=%s, %s=%s.%s:%s, " +

                             "%s=%s %s.%s:%s, %s=%s, %s=%d]",

                             "capturingClass", capturingClass,

                             "functionalInterfaceMethod", functionalInterfaceClass,

                               functionalInterfaceMethodName,

                               functionalInterfaceMethodSignature,

                             "implementation",

                               null,

                               implClass, implMethodName, implMethodSignature,

                             "instantiatedMethodType", instantiatedMethodType,

                             "numCaptured", capturedArgs.length);

    }

}