816 lines
34 KiB
Java
816 lines
34 KiB
Java
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/*
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* Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.lang.reflect;
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import java.lang.ref.Reference;
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import java.lang.ref.WeakReference;
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import java.security.AccessController;
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import java.security.Permission;
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import java.security.PrivilegedAction;
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import java.util.Arrays;
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import java.util.Collections;
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import java.util.HashMap;
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import java.util.HashSet;
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import java.util.Map;
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import java.util.Set;
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import java.util.List;
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import java.util.WeakHashMap;
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import sun.misc.ProxyGenerator;
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import sun.reflect.CallerSensitive;
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import sun.reflect.Reflection;
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import sun.reflect.misc.ReflectUtil;
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import sun.security.util.SecurityConstants;
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/**
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* {@code Proxy} provides static methods for creating dynamic proxy
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* classes and instances, and it is also the superclass of all
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* dynamic proxy classes created by those methods.
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*
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* <p>To create a proxy for some interface {@code Foo}:
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* <pre>
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* InvocationHandler handler = new MyInvocationHandler(...);
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* Class proxyClass = Proxy.getProxyClass(
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* Foo.class.getClassLoader(), new Class[] { Foo.class });
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* Foo f = (Foo) proxyClass.
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* getConstructor(new Class[] { InvocationHandler.class }).
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* newInstance(new Object[] { handler });
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* </pre>
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* or more simply:
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* <pre>
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* Foo f = (Foo) Proxy.newProxyInstance(Foo.class.getClassLoader(),
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* new Class[] { Foo.class },
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* handler);
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* </pre>
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*
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* <p>A <i>dynamic proxy class</i> (simply referred to as a <i>proxy
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* class</i> below) is a class that implements a list of interfaces
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* specified at runtime when the class is created, with behavior as
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* described below.
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*
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* A <i>proxy interface</i> is such an interface that is implemented
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* by a proxy class.
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*
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* A <i>proxy instance</i> is an instance of a proxy class.
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*
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* Each proxy instance has an associated <i>invocation handler</i>
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* object, which implements the interface {@link InvocationHandler}.
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* A method invocation on a proxy instance through one of its proxy
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* interfaces will be dispatched to the {@link InvocationHandler#invoke
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* invoke} method of the instance's invocation handler, passing the proxy
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* instance, a {@code java.lang.reflect.Method} object identifying
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* the method that was invoked, and an array of type {@code Object}
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* containing the arguments. The invocation handler processes the
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* encoded method invocation as appropriate and the result that it
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* returns will be returned as the result of the method invocation on
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* the proxy instance.
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*
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* <p>A proxy class has the following properties:
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*
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* <ul>
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* <li>Proxy classes are public, final, and not abstract.
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*
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* <li>The unqualified name of a proxy class is unspecified. The space
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* of class names that begin with the string {@code "$Proxy"}
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* should be, however, reserved for proxy classes.
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*
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* <li>A proxy class extends {@code java.lang.reflect.Proxy}.
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*
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* <li>A proxy class implements exactly the interfaces specified at its
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* creation, in the same order.
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*
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* <li>If a proxy class implements a non-public interface, then it will
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* be defined in the same package as that interface. Otherwise, the
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* package of a proxy class is also unspecified. Note that package
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* sealing will not prevent a proxy class from being successfully defined
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* in a particular package at runtime, and neither will classes already
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* defined by the same class loader and the same package with particular
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* signers.
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*
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* <li>Since a proxy class implements all of the interfaces specified at
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* its creation, invoking {@code getInterfaces} on its
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* {@code Class} object will return an array containing the same
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* list of interfaces (in the order specified at its creation), invoking
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* {@code getMethods} on its {@code Class} object will return
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* an array of {@code Method} objects that include all of the
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* methods in those interfaces, and invoking {@code getMethod} will
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* find methods in the proxy interfaces as would be expected.
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*
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* <li>The {@link Proxy#isProxyClass Proxy.isProxyClass} method will
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* return true if it is passed a proxy class-- a class returned by
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* {@code Proxy.getProxyClass} or the class of an object returned by
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* {@code Proxy.newProxyInstance}-- and false otherwise.
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*
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* <li>The {@code java.security.ProtectionDomain} of a proxy class
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* is the same as that of system classes loaded by the bootstrap class
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* loader, such as {@code java.lang.Object}, because the code for a
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* proxy class is generated by trusted system code. This protection
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* domain will typically be granted
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* {@code java.security.AllPermission}.
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*
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* <li>Each proxy class has one public constructor that takes one argument,
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* an implementation of the interface {@link InvocationHandler}, to set
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* the invocation handler for a proxy instance. Rather than having to use
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* the reflection API to access the public constructor, a proxy instance
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* can be also be created by calling the {@link Proxy#newProxyInstance
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* Proxy.newProxyInstance} method, which combines the actions of calling
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* {@link Proxy#getProxyClass Proxy.getProxyClass} with invoking the
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* constructor with an invocation handler.
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* </ul>
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*
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* <p>A proxy instance has the following properties:
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*
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* <ul>
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* <li>Given a proxy instance {@code proxy} and one of the
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* interfaces implemented by its proxy class {@code Foo}, the
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* following expression will return true:
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* <pre>
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* {@code proxy instanceof Foo}
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* </pre>
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* and the following cast operation will succeed (rather than throwing
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* a {@code ClassCastException}):
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* <pre>
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* {@code (Foo) proxy}
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* </pre>
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*
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* <li>Each proxy instance has an associated invocation handler, the one
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* that was passed to its constructor. The static
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* {@link Proxy#getInvocationHandler Proxy.getInvocationHandler} method
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* will return the invocation handler associated with the proxy instance
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* passed as its argument.
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*
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* <li>An interface method invocation on a proxy instance will be
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* encoded and dispatched to the invocation handler's {@link
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* InvocationHandler#invoke invoke} method as described in the
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* documentation for that method.
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*
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* <li>An invocation of the {@code hashCode},
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* {@code equals}, or {@code toString} methods declared in
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* {@code java.lang.Object} on a proxy instance will be encoded and
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* dispatched to the invocation handler's {@code invoke} method in
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* the same manner as interface method invocations are encoded and
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* dispatched, as described above. The declaring class of the
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* {@code Method} object passed to {@code invoke} will be
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* {@code java.lang.Object}. Other public methods of a proxy
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* instance inherited from {@code java.lang.Object} are not
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* overridden by a proxy class, so invocations of those methods behave
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* like they do for instances of {@code java.lang.Object}.
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* </ul>
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*
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* <h3>Methods Duplicated in Multiple Proxy Interfaces</h3>
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*
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* <p>When two or more interfaces of a proxy class contain a method with
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* the same name and parameter signature, the order of the proxy class's
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* interfaces becomes significant. When such a <i>duplicate method</i>
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* is invoked on a proxy instance, the {@code Method} object passed
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* to the invocation handler will not necessarily be the one whose
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* declaring class is assignable from the reference type of the interface
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* that the proxy's method was invoked through. This limitation exists
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* because the corresponding method implementation in the generated proxy
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* class cannot determine which interface it was invoked through.
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* Therefore, when a duplicate method is invoked on a proxy instance,
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* the {@code Method} object for the method in the foremost interface
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* that contains the method (either directly or inherited through a
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* superinterface) in the proxy class's list of interfaces is passed to
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* the invocation handler's {@code invoke} method, regardless of the
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* reference type through which the method invocation occurred.
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*
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* <p>If a proxy interface contains a method with the same name and
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* parameter signature as the {@code hashCode}, {@code equals},
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* or {@code toString} methods of {@code java.lang.Object},
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* when such a method is invoked on a proxy instance, the
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* {@code Method} object passed to the invocation handler will have
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* {@code java.lang.Object} as its declaring class. In other words,
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* the public, non-final methods of {@code java.lang.Object}
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* logically precede all of the proxy interfaces for the determination of
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* which {@code Method} object to pass to the invocation handler.
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*
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* <p>Note also that when a duplicate method is dispatched to an
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* invocation handler, the {@code invoke} method may only throw
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* checked exception types that are assignable to one of the exception
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* types in the {@code throws} clause of the method in <i>all</i> of
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* the proxy interfaces that it can be invoked through. If the
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* {@code invoke} method throws a checked exception that is not
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* assignable to any of the exception types declared by the method in one
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* of the proxy interfaces that it can be invoked through, then an
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* unchecked {@code UndeclaredThrowableException} will be thrown by
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* the invocation on the proxy instance. This restriction means that not
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* all of the exception types returned by invoking
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* {@code getExceptionTypes} on the {@code Method} object
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* passed to the {@code invoke} method can necessarily be thrown
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* successfully by the {@code invoke} method.
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*
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* @author Peter Jones
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* @see InvocationHandler
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* @since 1.3
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*/
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public class Proxy implements java.io.Serializable {
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private static final long serialVersionUID = -2222568056686623797L;
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/** prefix for all proxy class names */
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private final static String proxyClassNamePrefix = "$Proxy";
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/** parameter types of a proxy class constructor */
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private final static Class[] constructorParams =
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{ InvocationHandler.class };
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/** maps a class loader to the proxy class cache for that loader */
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private static Map<ClassLoader, Map<List<String>, Object>> loaderToCache
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= new WeakHashMap<>();
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/** marks that a particular proxy class is currently being generated */
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private static Object pendingGenerationMarker = new Object();
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/** next number to use for generation of unique proxy class names */
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private static long nextUniqueNumber = 0;
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private static Object nextUniqueNumberLock = new Object();
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/** set of all generated proxy classes, for isProxyClass implementation */
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private static Map<Class<?>, Void> proxyClasses =
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Collections.synchronizedMap(new WeakHashMap<Class<?>, Void>());
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/**
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* the invocation handler for this proxy instance.
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* @serial
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*/
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protected InvocationHandler h;
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/**
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* Prohibits instantiation.
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*/
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private Proxy() {
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}
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/**
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* Constructs a new {@code Proxy} instance from a subclass
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* (typically, a dynamic proxy class) with the specified value
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* for its invocation handler.
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*
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* @param h the invocation handler for this proxy instance
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*/
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protected Proxy(InvocationHandler h) {
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doNewInstanceCheck();
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this.h = h;
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}
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private static class ProxyAccessHelper {
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// The permission is implementation specific.
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static final Permission PROXY_PERMISSION =
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new ReflectPermission("proxyConstructorNewInstance");
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// These system properties are defined to provide a short-term
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// workaround if customers need to disable the new security checks.
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static final boolean allowNewInstance;
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static final boolean allowNullLoader;
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static {
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allowNewInstance = getBooleanProperty("sun.reflect.proxy.allowsNewInstance");
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allowNullLoader = getBooleanProperty("sun.reflect.proxy.allowsNullLoader");
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}
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private static boolean getBooleanProperty(final String key) {
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String s = AccessController.doPrivileged(new PrivilegedAction<String>() {
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public String run() {
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return System.getProperty(key);
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}
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});
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return Boolean.valueOf(s);
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}
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static boolean needsNewInstanceCheck(Class<?> proxyClass) {
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if (!Proxy.isProxyClass(proxyClass) || allowNewInstance) {
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return false;
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}
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if (ReflectUtil.isNonPublicProxyClass(proxyClass)) {
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for (Class<?> intf : proxyClass.getInterfaces()) {
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if (!Modifier.isPublic(intf.getModifiers())) {
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return true;
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}
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}
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}
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return false;
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}
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}
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/*
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* Access check on a proxy class that implements any non-public interface.
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*
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* @throws SecurityException if a security manager exists, and
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* the caller does not have the permission.
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*/
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private void doNewInstanceCheck() {
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SecurityManager sm = System.getSecurityManager();
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Class<?> proxyClass = this.getClass();
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if (sm != null && ProxyAccessHelper.needsNewInstanceCheck(proxyClass)) {
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try {
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sm.checkPermission(ProxyAccessHelper.PROXY_PERMISSION);
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} catch (SecurityException e) {
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throw new SecurityException("Not allowed to construct a Proxy "
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+ "instance that implements a non-public interface", e);
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}
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}
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}
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/**
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* Returns the {@code java.lang.Class} object for a proxy class
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* given a class loader and an array of interfaces. The proxy class
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* will be defined by the specified class loader and will implement
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* all of the supplied interfaces. If a proxy class for the same
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* permutation of interfaces has already been defined by the class
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* loader, then the existing proxy class will be returned; otherwise,
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* a proxy class for those interfaces will be generated dynamically
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* and defined by the class loader.
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*
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* <p>There are several restrictions on the parameters that may be
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* passed to {@code Proxy.getProxyClass}:
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*
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* <ul>
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* <li>All of the {@code Class} objects in the
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* {@code interfaces} array must represent interfaces, not
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* classes or primitive types.
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*
|
||
|
|
* <li>No two elements in the {@code interfaces} array may
|
||
|
|
* refer to identical {@code Class} objects.
|
||
|
|
*
|
||
|
|
* <li>All of the interface types must be visible by name through the
|
||
|
|
* specified class loader. In other words, for class loader
|
||
|
|
* {@code cl} and every interface {@code i}, the following
|
||
|
|
* expression must be true:
|
||
|
|
* <pre>
|
||
|
|
* Class.forName(i.getName(), false, cl) == i
|
||
|
|
* </pre>
|
||
|
|
*
|
||
|
|
* <li>All non-public interfaces must be in the same package;
|
||
|
|
* otherwise, it would not be possible for the proxy class to
|
||
|
|
* implement all of the interfaces, regardless of what package it is
|
||
|
|
* defined in.
|
||
|
|
*
|
||
|
|
* <li>For any set of member methods of the specified interfaces
|
||
|
|
* that have the same signature:
|
||
|
|
* <ul>
|
||
|
|
* <li>If the return type of any of the methods is a primitive
|
||
|
|
* type or void, then all of the methods must have that same
|
||
|
|
* return type.
|
||
|
|
* <li>Otherwise, one of the methods must have a return type that
|
||
|
|
* is assignable to all of the return types of the rest of the
|
||
|
|
* methods.
|
||
|
|
* </ul>
|
||
|
|
*
|
||
|
|
* <li>The resulting proxy class must not exceed any limits imposed
|
||
|
|
* on classes by the virtual machine. For example, the VM may limit
|
||
|
|
* the number of interfaces that a class may implement to 65535; in
|
||
|
|
* that case, the size of the {@code interfaces} array must not
|
||
|
|
* exceed 65535.
|
||
|
|
* </ul>
|
||
|
|
*
|
||
|
|
* <p>If any of these restrictions are violated,
|
||
|
|
* {@code Proxy.getProxyClass} will throw an
|
||
|
|
* {@code IllegalArgumentException}. If the {@code interfaces}
|
||
|
|
* array argument or any of its elements are {@code null}, a
|
||
|
|
* {@code NullPointerException} will be thrown.
|
||
|
|
*
|
||
|
|
* <p>Note that the order of the specified proxy interfaces is
|
||
|
|
* significant: two requests for a proxy class with the same combination
|
||
|
|
* of interfaces but in a different order will result in two distinct
|
||
|
|
* proxy classes.
|
||
|
|
*
|
||
|
|
* @param loader the class loader to define the proxy class
|
||
|
|
* @param interfaces the list of interfaces for the proxy class
|
||
|
|
* to implement
|
||
|
|
* @return a proxy class that is defined in the specified class loader
|
||
|
|
* and that implements the specified interfaces
|
||
|
|
* @throws IllegalArgumentException if any of the restrictions on the
|
||
|
|
* parameters that may be passed to {@code getProxyClass}
|
||
|
|
* are violated
|
||
|
|
* @throws NullPointerException if the {@code interfaces} array
|
||
|
|
* argument or any of its elements are {@code null}
|
||
|
|
*/
|
||
|
|
@CallerSensitive
|
||
|
|
public static Class<?> getProxyClass(ClassLoader loader,
|
||
|
|
Class<?>... interfaces)
|
||
|
|
throws IllegalArgumentException
|
||
|
|
{
|
||
|
|
SecurityManager sm = System.getSecurityManager();
|
||
|
|
if (sm != null) {
|
||
|
|
checkProxyAccess(Reflection.getCallerClass(), loader, interfaces);
|
||
|
|
}
|
||
|
|
|
||
|
|
return getProxyClass0(loader, interfaces);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Check permissions required to create a Proxy class.
|
||
|
|
*
|
||
|
|
* To define a proxy class, it performs the access checks as in
|
||
|
|
* Class.forName (VM will invoke ClassLoader.checkPackageAccess):
|
||
|
|
* 1. "getClassLoader" permission check if loader == null
|
||
|
|
* 2. checkPackageAccess on the interfaces it implements
|
||
|
|
*
|
||
|
|
* To get a constructor and new instance of a proxy class, it performs
|
||
|
|
* the package access check on the interfaces it implements
|
||
|
|
* as in Class.getConstructor.
|
||
|
|
*
|
||
|
|
* If an interface is non-public, the proxy class must be defined by
|
||
|
|
* the defining loader of the interface. If the caller's class loader
|
||
|
|
* is not the same as the defining loader of the interface, the VM
|
||
|
|
* will throw IllegalAccessError when the generated proxy class is
|
||
|
|
* being defined via the defineClass0 method.
|
||
|
|
*/
|
||
|
|
private static void checkProxyAccess(Class<?> caller,
|
||
|
|
ClassLoader loader,
|
||
|
|
Class<?>... interfaces)
|
||
|
|
{
|
||
|
|
SecurityManager sm = System.getSecurityManager();
|
||
|
|
if (sm != null) {
|
||
|
|
ClassLoader ccl = caller.getClassLoader();
|
||
|
|
if (loader == null && ccl != null) {
|
||
|
|
if (!ProxyAccessHelper.allowNullLoader) {
|
||
|
|
sm.checkPermission(SecurityConstants.GET_CLASSLOADER_PERMISSION);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
ReflectUtil.checkProxyPackageAccess(ccl, interfaces);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Generate a proxy class. Must call the checkProxyAccess method
|
||
|
|
* to perform permission checks before calling this.
|
||
|
|
*/
|
||
|
|
private static Class<?> getProxyClass0(ClassLoader loader,
|
||
|
|
Class<?>... interfaces) {
|
||
|
|
if (interfaces.length > 65535) {
|
||
|
|
throw new IllegalArgumentException("interface limit exceeded");
|
||
|
|
}
|
||
|
|
|
||
|
|
Class<?> proxyClass = null;
|
||
|
|
|
||
|
|
/* collect interface names to use as key for proxy class cache */
|
||
|
|
String[] interfaceNames = new String[interfaces.length];
|
||
|
|
|
||
|
|
// for detecting duplicates
|
||
|
|
Set<Class<?>> interfaceSet = new HashSet<>();
|
||
|
|
|
||
|
|
for (int i = 0; i < interfaces.length; i++) {
|
||
|
|
/*
|
||
|
|
* Verify that the class loader resolves the name of this
|
||
|
|
* interface to the same Class object.
|
||
|
|
*/
|
||
|
|
String interfaceName = interfaces[i].getName();
|
||
|
|
Class<?> interfaceClass = null;
|
||
|
|
try {
|
||
|
|
interfaceClass = Class.forName(interfaceName, false, loader);
|
||
|
|
} catch (ClassNotFoundException e) {
|
||
|
|
}
|
||
|
|
if (interfaceClass != interfaces[i]) {
|
||
|
|
throw new IllegalArgumentException(
|
||
|
|
interfaces[i] + " is not visible from class loader");
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Verify that the Class object actually represents an
|
||
|
|
* interface.
|
||
|
|
*/
|
||
|
|
if (!interfaceClass.isInterface()) {
|
||
|
|
throw new IllegalArgumentException(
|
||
|
|
interfaceClass.getName() + " is not an interface");
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Verify that this interface is not a duplicate.
|
||
|
|
*/
|
||
|
|
if (interfaceSet.contains(interfaceClass)) {
|
||
|
|
throw new IllegalArgumentException(
|
||
|
|
"repeated interface: " + interfaceClass.getName());
|
||
|
|
}
|
||
|
|
interfaceSet.add(interfaceClass);
|
||
|
|
|
||
|
|
interfaceNames[i] = interfaceName;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Using string representations of the proxy interfaces as
|
||
|
|
* keys in the proxy class cache (instead of their Class
|
||
|
|
* objects) is sufficient because we require the proxy
|
||
|
|
* interfaces to be resolvable by name through the supplied
|
||
|
|
* class loader, and it has the advantage that using a string
|
||
|
|
* representation of a class makes for an implicit weak
|
||
|
|
* reference to the class.
|
||
|
|
*/
|
||
|
|
List<String> key = Arrays.asList(interfaceNames);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Find or create the proxy class cache for the class loader.
|
||
|
|
*/
|
||
|
|
Map<List<String>, Object> cache;
|
||
|
|
synchronized (loaderToCache) {
|
||
|
|
cache = loaderToCache.get(loader);
|
||
|
|
if (cache == null) {
|
||
|
|
cache = new HashMap<>();
|
||
|
|
loaderToCache.put(loader, cache);
|
||
|
|
}
|
||
|
|
/*
|
||
|
|
* This mapping will remain valid for the duration of this
|
||
|
|
* method, without further synchronization, because the mapping
|
||
|
|
* will only be removed if the class loader becomes unreachable.
|
||
|
|
*/
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Look up the list of interfaces in the proxy class cache using
|
||
|
|
* the key. This lookup will result in one of three possible
|
||
|
|
* kinds of values:
|
||
|
|
* null, if there is currently no proxy class for the list of
|
||
|
|
* interfaces in the class loader,
|
||
|
|
* the pendingGenerationMarker object, if a proxy class for the
|
||
|
|
* list of interfaces is currently being generated,
|
||
|
|
* or a weak reference to a Class object, if a proxy class for
|
||
|
|
* the list of interfaces has already been generated.
|
||
|
|
*/
|
||
|
|
synchronized (cache) {
|
||
|
|
/*
|
||
|
|
* Note that we need not worry about reaping the cache for
|
||
|
|
* entries with cleared weak references because if a proxy class
|
||
|
|
* has been garbage collected, its class loader will have been
|
||
|
|
* garbage collected as well, so the entire cache will be reaped
|
||
|
|
* from the loaderToCache map.
|
||
|
|
*/
|
||
|
|
do {
|
||
|
|
Object value = cache.get(key);
|
||
|
|
if (value instanceof Reference) {
|
||
|
|
proxyClass = (Class<?>) ((Reference) value).get();
|
||
|
|
}
|
||
|
|
if (proxyClass != null) {
|
||
|
|
// proxy class already generated: return it
|
||
|
|
return proxyClass;
|
||
|
|
} else if (value == pendingGenerationMarker) {
|
||
|
|
// proxy class being generated: wait for it
|
||
|
|
try {
|
||
|
|
cache.wait();
|
||
|
|
} catch (InterruptedException e) {
|
||
|
|
/*
|
||
|
|
* The class generation that we are waiting for should
|
||
|
|
* take a small, bounded time, so we can safely ignore
|
||
|
|
* thread interrupts here.
|
||
|
|
*/
|
||
|
|
}
|
||
|
|
continue;
|
||
|
|
} else {
|
||
|
|
/*
|
||
|
|
* No proxy class for this list of interfaces has been
|
||
|
|
* generated or is being generated, so we will go and
|
||
|
|
* generate it now. Mark it as pending generation.
|
||
|
|
*/
|
||
|
|
cache.put(key, pendingGenerationMarker);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
} while (true);
|
||
|
|
}
|
||
|
|
|
||
|
|
try {
|
||
|
|
String proxyPkg = null; // package to define proxy class in
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Record the package of a non-public proxy interface so that the
|
||
|
|
* proxy class will be defined in the same package. Verify that
|
||
|
|
* all non-public proxy interfaces are in the same package.
|
||
|
|
*/
|
||
|
|
for (int i = 0; i < interfaces.length; i++) {
|
||
|
|
int flags = interfaces[i].getModifiers();
|
||
|
|
if (!Modifier.isPublic(flags)) {
|
||
|
|
String name = interfaces[i].getName();
|
||
|
|
int n = name.lastIndexOf('.');
|
||
|
|
String pkg = ((n == -1) ? "" : name.substring(0, n + 1));
|
||
|
|
if (proxyPkg == null) {
|
||
|
|
proxyPkg = pkg;
|
||
|
|
} else if (!pkg.equals(proxyPkg)) {
|
||
|
|
throw new IllegalArgumentException(
|
||
|
|
"non-public interfaces from different packages");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (proxyPkg == null) {
|
||
|
|
// if no non-public proxy interfaces, use com.sun.proxy package
|
||
|
|
proxyPkg = ReflectUtil.PROXY_PACKAGE + ".";
|
||
|
|
}
|
||
|
|
|
||
|
|
generate: do
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* Choose a name for the proxy class to generate.
|
||
|
|
*/
|
||
|
|
long num;
|
||
|
|
synchronized (nextUniqueNumberLock) {
|
||
|
|
num = nextUniqueNumber++;
|
||
|
|
}
|
||
|
|
String proxyName = proxyPkg + proxyClassNamePrefix + num;
|
||
|
|
/*
|
||
|
|
* Verify that the class loader hasn't already
|
||
|
|
* defined a class with the chosen name.
|
||
|
|
*/
|
||
|
|
|
||
|
|
proxyClass = getPrecompiledProxy(loader, proxyName, interfaces);
|
||
|
|
if (proxyClass != null)
|
||
|
|
break generate;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Generate the specified proxy class.
|
||
|
|
*/
|
||
|
|
byte[] proxyClassFile = ProxyGenerator.generateProxyClass(
|
||
|
|
proxyName, interfaces);
|
||
|
|
try {
|
||
|
|
proxyClass = defineClass0(loader, proxyName,
|
||
|
|
proxyClassFile, 0, proxyClassFile.length);
|
||
|
|
} catch (ClassFormatError e) {
|
||
|
|
/*
|
||
|
|
* A ClassFormatError here means that (barring bugs in the
|
||
|
|
* proxy class generation code) there was some other
|
||
|
|
* invalid aspect of the arguments supplied to the proxy
|
||
|
|
* class creation (such as virtual machine limitations
|
||
|
|
* exceeded).
|
||
|
|
*/
|
||
|
|
throw new IllegalArgumentException(e.toString());
|
||
|
|
}
|
||
|
|
}
|
||
|
|
while (false);
|
||
|
|
// add to set of all generated proxy classes, for isProxyClass
|
||
|
|
proxyClasses.put(proxyClass, null);
|
||
|
|
|
||
|
|
} finally {
|
||
|
|
/*
|
||
|
|
* We must clean up the "pending generation" state of the proxy
|
||
|
|
* class cache entry somehow. If a proxy class was successfully
|
||
|
|
* generated, store it in the cache (with a weak reference);
|
||
|
|
* otherwise, remove the reserved entry. In all cases, notify
|
||
|
|
* all waiters on reserved entries in this cache.
|
||
|
|
*/
|
||
|
|
synchronized (cache) {
|
||
|
|
if (proxyClass != null) {
|
||
|
|
cache.put(key, new WeakReference<Class<?>>(proxyClass));
|
||
|
|
} else {
|
||
|
|
cache.remove(key);
|
||
|
|
}
|
||
|
|
cache.notifyAll();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return proxyClass;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns an instance of a proxy class for the specified interfaces
|
||
|
|
* that dispatches method invocations to the specified invocation
|
||
|
|
* handler. This method is equivalent to:
|
||
|
|
* <pre>
|
||
|
|
* Proxy.getProxyClass(loader, interfaces).
|
||
|
|
* getConstructor(new Class[] { InvocationHandler.class }).
|
||
|
|
* newInstance(new Object[] { handler });
|
||
|
|
* </pre>
|
||
|
|
*
|
||
|
|
* <p>{@code Proxy.newProxyInstance} throws
|
||
|
|
* {@code IllegalArgumentException} for the same reasons that
|
||
|
|
* {@code Proxy.getProxyClass} does.
|
||
|
|
*
|
||
|
|
* @param loader the class loader to define the proxy class
|
||
|
|
* @param interfaces the list of interfaces for the proxy class
|
||
|
|
* to implement
|
||
|
|
* @param h the invocation handler to dispatch method invocations to
|
||
|
|
* @return a proxy instance with the specified invocation handler of a
|
||
|
|
* proxy class that is defined by the specified class loader
|
||
|
|
* and that implements the specified interfaces
|
||
|
|
* @throws IllegalArgumentException if any of the restrictions on the
|
||
|
|
* parameters that may be passed to {@code getProxyClass}
|
||
|
|
* are violated
|
||
|
|
* @throws NullPointerException if the {@code interfaces} array
|
||
|
|
* argument or any of its elements are {@code null}, or
|
||
|
|
* if the invocation handler, {@code h}, is
|
||
|
|
* {@code null}
|
||
|
|
*/
|
||
|
|
@CallerSensitive
|
||
|
|
public static Object newProxyInstance(ClassLoader loader,
|
||
|
|
Class<?>[] interfaces,
|
||
|
|
InvocationHandler h)
|
||
|
|
throws IllegalArgumentException
|
||
|
|
{
|
||
|
|
if (h == null) {
|
||
|
|
throw new NullPointerException();
|
||
|
|
}
|
||
|
|
|
||
|
|
final SecurityManager sm = System.getSecurityManager();
|
||
|
|
if (sm != null) {
|
||
|
|
checkProxyAccess(Reflection.getCallerClass(), loader, interfaces);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Look up or generate the designated proxy class.
|
||
|
|
*/
|
||
|
|
Class<?> cl = getProxyClass0(loader, interfaces);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Invoke its constructor with the designated invocation handler.
|
||
|
|
*/
|
||
|
|
try {
|
||
|
|
final Constructor<?> cons = cl.getConstructor(constructorParams);
|
||
|
|
final InvocationHandler ih = h;
|
||
|
|
if (sm != null && ProxyAccessHelper.needsNewInstanceCheck(cl)) {
|
||
|
|
// create proxy instance with doPrivilege as the proxy class may
|
||
|
|
// implement non-public interfaces that requires a special permission
|
||
|
|
return AccessController.doPrivileged(new PrivilegedAction<Object>() {
|
||
|
|
public Object run() {
|
||
|
|
return newInstance(cons, ih);
|
||
|
|
}
|
||
|
|
});
|
||
|
|
} else {
|
||
|
|
return newInstance(cons, ih);
|
||
|
|
}
|
||
|
|
} catch (NoSuchMethodException e) {
|
||
|
|
throw new InternalError(e.toString());
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private static Object newInstance(Constructor<?> cons, InvocationHandler h) {
|
||
|
|
try {
|
||
|
|
return cons.newInstance(new Object[] {h} );
|
||
|
|
} catch (IllegalAccessException | InstantiationException e) {
|
||
|
|
throw new InternalError(e.toString());
|
||
|
|
} catch (InvocationTargetException e) {
|
||
|
|
Throwable t = e.getCause();
|
||
|
|
if (t instanceof RuntimeException) {
|
||
|
|
throw (RuntimeException) t;
|
||
|
|
} else {
|
||
|
|
throw new InternalError(t.toString());
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns true if and only if the specified class was dynamically
|
||
|
|
* generated to be a proxy class using the {@code getProxyClass}
|
||
|
|
* method or the {@code newProxyInstance} method.
|
||
|
|
*
|
||
|
|
* <p>The reliability of this method is important for the ability
|
||
|
|
* to use it to make security decisions, so its implementation should
|
||
|
|
* not just test if the class in question extends {@code Proxy}.
|
||
|
|
*
|
||
|
|
* @param cl the class to test
|
||
|
|
* @return {@code true} if the class is a proxy class and
|
||
|
|
* {@code false} otherwise
|
||
|
|
* @throws NullPointerException if {@code cl} is {@code null}
|
||
|
|
*/
|
||
|
|
public static boolean isProxyClass(Class<?> cl) {
|
||
|
|
if (cl == null) {
|
||
|
|
throw new NullPointerException();
|
||
|
|
}
|
||
|
|
|
||
|
|
return proxyClasses.containsKey(cl);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns the invocation handler for the specified proxy instance.
|
||
|
|
*
|
||
|
|
* @param proxy the proxy instance to return the invocation handler for
|
||
|
|
* @return the invocation handler for the proxy instance
|
||
|
|
* @throws IllegalArgumentException if the argument is not a
|
||
|
|
* proxy instance
|
||
|
|
*/
|
||
|
|
public static InvocationHandler getInvocationHandler(Object proxy)
|
||
|
|
throws IllegalArgumentException
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* Verify that the object is actually a proxy instance.
|
||
|
|
*/
|
||
|
|
if (!isProxyClass(proxy.getClass())) {
|
||
|
|
throw new IllegalArgumentException("not a proxy instance");
|
||
|
|
}
|
||
|
|
|
||
|
|
Proxy p = (Proxy) proxy;
|
||
|
|
return p.h;
|
||
|
|
}
|
||
|
|
|
||
|
|
private static native Class defineClass0(ClassLoader loader, String name,
|
||
|
|
byte[] b, int off, int len);
|
||
|
|
|
||
|
|
private static native Class<?> getPrecompiledProxy(ClassLoader loader, String proxyName, Class[] interfaces);
|
||
|
|
}
|