83 lines
1.8 KiB
Java
83 lines
1.8 KiB
Java
/*
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* Proxy.java
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*
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* Copyright (c) 2007 Vreixo Formoso
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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* See COPYING file for details.
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*/
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package org.pykix.libburnia.bindings;
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import java.lang.ref.WeakReference;
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import java.util.HashMap;
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/**
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* Wrapper around a native C resource, i.e., a pointer.
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*
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* <p>
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* This also keeps track of all Java objects that are a wrapper around
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* a C object, to prevent replication of objects when retrieved from C
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* side.
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*
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* <p>
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* <b>This class is a implementation detail, that should be never user
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* by a developer</b>
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*
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* @author Vreixo Formoso
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* @since 0.1
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*/
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public abstract class Proxy {
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/** Pointer to C object. */
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private final long pointer;
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/** Keeps track of existing pointers. */
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private static final HashMap<Long, WeakReference<Proxy>> proxies =
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new HashMap<Long, WeakReference<Proxy>>();
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protected Proxy(long ptr) {
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assert ptr != 0 : "Can't proxy a NULL pointer";
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assert proxies.get(ptr) == null :
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"Can't create a pointer for an existing proxy";
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pointer = ptr;
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proxies.put( ptr, new WeakReference<Proxy>(this) );
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}
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@Override
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protected void finalize() throws Throwable {
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super.finalize();
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proxies.remove(pointer);
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}
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/**
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* Get C pointer for a Proxy.
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*
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* @param obj
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* @return
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*/
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protected static long pointerOf(Proxy obj) {
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return obj.pointer;
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}
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/**
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* Get the proxy registered for a pointer.
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*
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* @param ptr
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* Pointer
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* @return
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* The Proxy or <code>null</code> if no Proxy is registered.
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*/
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protected static Proxy proxyFor(long ptr) {
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WeakReference<Proxy> ref = proxies.get(ptr);
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return ref == null ? null : ref.get();
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}
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}
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