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1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
2 : /*
3 : * This file is part of the LibreOffice project.
4 : *
5 : * This Source Code Form is subject to the terms of the Mozilla Public
6 : * License, v. 2.0. If a copy of the MPL was not distributed with this
7 : * file, You can obtain one at http://mozilla.org/MPL/2.0/.
8 : *
9 : * This file incorporates work covered by the following license notice:
10 : *
11 : * Licensed to the Apache Software Foundation (ASF) under one or more
12 : * contributor license agreements. See the NOTICE file distributed
13 : * with this work for additional information regarding copyright
14 : * ownership. The ASF licenses this file to you under the Apache
15 : * License, Version 2.0 (the "License"); you may not use this file
16 : * except in compliance with the License. You may obtain a copy of
17 : * the License at http://www.apache.org/licenses/LICENSE-2.0 .
18 : */
19 :
20 : #ifndef INCLUDED_JVMACCESS_VIRTUALMACHINE_HXX
21 : #define INCLUDED_JVMACCESS_VIRTUALMACHINE_HXX
22 :
23 : #include <jvmaccess/jvmaccessdllapi.h>
24 : #include <rtl/ref.hxx>
25 : #include <salhelper/simplereferenceobject.hxx>
26 :
27 : #include "jni.h"
28 :
29 : namespace jvmaccess {
30 :
31 : /** An encapsulating wrapper around a Java virtual machine.
32 : */
33 : class JVMACCESS_DLLPUBLIC VirtualMachine: public salhelper::SimpleReferenceObject
34 : {
35 : public:
36 : /** A helper to attach a thread to a Java virtual machine.
37 :
38 : @descr
39 : Upon construction of a guard the current thread is attached to the
40 : virtual machine, and upon destruction of the guard the thread is
41 : detached again. For any one thread, multiple instances of this class
42 : may be used in a stack-like fashion (care is taken to only really
43 : detach the thread from the virtual machine upon destruction of the guard
44 : at the bottom of the stack).
45 : */
46 : class JVMACCESS_DLLPUBLIC AttachGuard
47 : {
48 : public:
49 : /** An exception indicating failure to create an AttachGuard.
50 : */
51 : class JVMACCESS_DLLPUBLIC CreationException
52 : {
53 : public:
54 : CreationException();
55 :
56 : CreationException(CreationException const &);
57 :
58 : virtual ~CreationException();
59 :
60 : CreationException & operator =(CreationException const &);
61 : };
62 :
63 : /** Attach the current thread to a virtual machine.
64 :
65 : @param rMachine
66 : The virtual machine to attach to. Must not be a null reference.
67 :
68 : @exception CreationException
69 : Thrown in case attaching fails (due to a JNI problem).
70 : */
71 : explicit AttachGuard(rtl::Reference< VirtualMachine > const & rMachine);
72 :
73 : /** Detach the current thread from the virtual machine again.
74 : */
75 : ~AttachGuard();
76 :
77 : /** Get a JNI environment pointer for the current thread.
78 :
79 : @return
80 : A valid JNI environment pointer. Will never be null.
81 : */
82 0 : inline JNIEnv * getEnvironment() const { return m_pEnvironment; }
83 :
84 : private:
85 : AttachGuard(AttachGuard &); // not implemented
86 : void operator =(AttachGuard); // not implemented
87 :
88 : rtl::Reference< VirtualMachine > m_xMachine;
89 : JNIEnv * m_pEnvironment;
90 : bool m_bDetach;
91 : };
92 :
93 : /** Create a wrapper around a Java virtual machine.
94 :
95 : @param pVm
96 : A JNI pointer to virtual machine. Must not be null.
97 :
98 : @param nVersion
99 : The JNI version of the virtual machine pointed to by pVm. Must be at
100 : least JNI_VERSION_1_2. This parameter should be of type jint, not int,
101 : but at least on some platforms the definition of jint changed from
102 : JDK 1.3 (long) to JDK 1.4 (int), so that the mangled C++ name of the
103 : constructor would depend on the JDK version used at compile time.
104 :
105 : @param bDestroy
106 : Whether to destroy the virtual machine when destructing the wrapper
107 : (i.e., whether the wrapper owns the virtual machine pointed to by pVm).
108 :
109 : @param pMainThreadEnv
110 : A valid JNI environment pointer for the current thread; must not be
111 : null. The current thread must be "initially attached" to the virtual
112 : machine while this constructor is being called (i.e., it must be the
113 : thread that has called JNI_CreateJavaVM in case the virtual machine has
114 : been started via the JNI Invocation API, and it must not already have
115 : called DetachCurrentThread; or it must be executing native code called
116 : from a "primordial" virtual machine). This environment pointer was
117 : formerly used to obtain a reference to the thread's current context
118 : class loader (java.lang.Thread.getCurrentClassLoader; if later a native
119 : thread was attached to the virtual machine, that thread's context class
120 : loader would be null, so the AttachGuard first of all set it to the
121 : saved value; this feature has been removed again for performance reasons
122 : and because the default context class loader is often not useful, so
123 : that code relying on a context class loader has to set one explicitly,
124 : anyway). This parameter is currently unused (but may be used again in
125 : the future).
126 : */
127 : VirtualMachine(JavaVM * pVm, int nVersion, bool bDestroy,
128 : JNIEnv * pMainThreadEnv);
129 :
130 : private:
131 : VirtualMachine(VirtualMachine &); // not implemented
132 : void operator =(VirtualMachine); // not implemented
133 :
134 : virtual ~VirtualMachine();
135 :
136 : JNIEnv * attachThread(bool * pAttached) const;
137 :
138 : void detachThread() const;
139 :
140 : JavaVM * m_pVm;
141 : jint m_nVersion;
142 : bool m_bDestroy;
143 :
144 : friend class AttachGuard; // to access attachThread, detachThread
145 : };
146 :
147 : }
148 :
149 : #endif // INCLUDED_JVMACCESS_VIRTUALMACHINE_HXX
150 :
151 : /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
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