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Diffstat (limited to 'jurt/com/sun/star/lib/uno/environments/java/java_environment.java')
| -rw-r--r-- | jurt/com/sun/star/lib/uno/environments/java/java_environment.java | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/jurt/com/sun/star/lib/uno/environments/java/java_environment.java b/jurt/com/sun/star/lib/uno/environments/java/java_environment.java new file mode 100644 index 000000000000..7be0f9e5366d --- /dev/null +++ b/jurt/com/sun/star/lib/uno/environments/java/java_environment.java @@ -0,0 +1,311 @@ +/************************************************************************* + * + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. + * + * Copyright 2000, 2010 Oracle and/or its affiliates. + * + * OpenOffice.org - a multi-platform office productivity suite + * + * This file is part of OpenOffice.org. + * + * OpenOffice.org is free software: you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License version 3 + * only, as published by the Free Software Foundation. + * + * OpenOffice.org 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 Lesser General Public License version 3 for more details + * (a copy is included in the LICENSE file that accompanied this code). + * + * You should have received a copy of the GNU Lesser General Public License + * version 3 along with OpenOffice.org. If not, see + * <http://www.openoffice.org/license.html> + * for a copy of the LGPLv3 License. + * + ************************************************************************/ + +package com.sun.star.lib.uno.environments.java; + +import com.sun.star.uno.IEnvironment; +import com.sun.star.uno.Type; +import com.sun.star.uno.UnoRuntime; +import java.lang.ref.ReferenceQueue; +import java.lang.ref.WeakReference; +import java.util.HashMap; +import java.util.Iterator; + +/** + * The java_environment is the environment where objects and + * interfaces are registered, which are mapped out of java or + * into java. + * + * <p>The java_environment implements the <code>IEnvironment</code> interface + * defined in the uno runtime.</p> + * + * @see com.sun.star.uno.UnoRuntime + * @see com.sun.star.uno.IEnvironment + * @since UDK1.0 + */ +public final class java_environment implements IEnvironment { + public java_environment(Object context) { + this.context = context; + } + + // @see com.sun.star.uno.IEnvironment#getContext + public Object getContext() { + return context; + } + + // @see com.sun.star.uno.IEnvironment#getName + public String getName() { + return "java"; + } + + // @see com.sun.star.uno.IEnvironment#registerInterface + public Object registerInterface(Object object, String[] oid, Type type) { + if (oid[0] == null) { + oid[0] = UnoRuntime.generateOid(object); + } + return (isProxy(object) ? proxies : localObjects).register( + object, oid[0], type); + } + + /** + * You have to revoke ANY interface that has been registered via this + * method. + * + * @param oid object id of interface to be revoked + * @param type the type description of the interface + * @see com.sun.star.uno.IEnvironment#revokeInterface + */ + public void revokeInterface(String oid, Type type) { + if (!proxies.revoke(oid, type)) { + localObjects.revoke(oid, type); + } + } + + /** + * Retrieves an interface identified by its object id and type from this + * environment. + * + * @param oid object id of interface to be retrieved + * @param type the type description of the interface to be retrieved + * @see com.sun.star.uno.IEnvironment#getRegisteredInterface + */ + public Object getRegisteredInterface(String oid, Type type) { + Object o = proxies.get(oid, type); + if (o == null) { + o = localObjects.get(oid, type); + } + return o; + } + + /** + * Retrieves the object identifier for a registered interface from this + * environment. + * + * @param object a registered interface + * @see com.sun.star.uno.IEnvironment#getRegisteredObjectIdentifier + */ + public String getRegisteredObjectIdentifier(Object object) { + return UnoRuntime.generateOid(object); + } + + // @see com.sun.star.uno.IEnvironment#list + public void list() { +// TODO??? +// synchronized (proxies) { +// System.err.println("##### " + getClass().getName() + ".list: " +// + getName() + ", " + getContext()); +// for (Iterator it = proxies.values().iterator(); it.hasNext();) { +// System.err.println("#### entry: " + it.next()); +// } +// } + } + + /** + * Revokes all registered proxy interfaces. + * + * <p>This method should be part of <code>IEnvironment</code>. It is called + * from <code>com.sun.star.lib.uno.bridges.java_remote.<!-- + * -->java_remote_bridge.dispose</code>.</p> + */ + public void revokeAllProxies() { + proxies.clear(); + } + + // TODO What's this??? java.lang.Object#equals requires reflexivity... + // + // Maybe this was hacked in so that different bridges use different + // instances of java_environment. That is desirable for the following + // reason: An OID is bridged in over bridge A, a proxy is created on the + // Java side, and recorded in the java_environment. The same OID is then + // bridged in over another bridge B. If there were only one + // java_environment shared by both bridges, the proxy from bridge A would be + // reused. If now bridge A is taken down programatically (e.g., because + // some controlling code somehow deduced that no objects are mapped over + // that bridge any longer), but the proxy is still used by bridge B, using + // the proxy would now result in errors. The explicit API to control + // bridges forbids to transparently share proxies between bridges, and using + // different java_environment instances for different bridges is the way to + // enforce this. + public boolean equals(Object obj) { + return false; + } + + private static final class Registry { + public synchronized Object register( + Object object, String oid, Type type) + { + cleanUp(); + Level1Entry l1 = level1map.get(oid); + if (l1 != null) { + Level2Entry l2 = l1.level2map.get(type); + if (l2 != null) { + Object o = l2.get(); + if (o != null) { + l2.acquire(); + return o; + } + } + } + // TODO If a holder references an unreachable object, but still has + // a positive count, it is replaced with a new holder (referencing a + // reachable object, and with a count of 1). Any later calls to + // revoke that should decrement the count of the previous holder + // would now decrement the count of the new holder, removing it + // prematurely. This is a design flaw that will be fixed when + // IEnvironment.revokeInterface is changed to no longer use + // counting. (And this problem is harmless, as currently a holder + // either references a strongly held object and uses register/revoke + // to control it, or references a weakly held proxy and never + // revokes it.) + if (l1 == null) { + l1 = new Level1Entry(); + level1map.put(oid, l1); + } + l1.level2map.put(type, new Level2Entry(oid, type, object, queue)); + return object; + } + + public synchronized boolean revoke(String oid, Type type) { + Level1Entry l1 = level1map.get(oid); + Level2Entry l2 = null; + if (l1 != null) { + l2 = l1.level2map.get(type); + if (l2 != null && l2.release()) { + removeLevel2Entry(l1, oid, type); + } + } + cleanUp(); + return l2 != null; + } + + public synchronized Object get(String oid, Type type) { + Level1Entry l1 = level1map.get(oid); + return l1 == null ? null : l1.find(type); + } + + public synchronized void clear() { + level1map.clear(); + cleanUp(); + } + + // must only be called while synchronized on this Registry: + private void cleanUp() { + for (;;) { + Level2Entry l2 = (Level2Entry) queue.poll(); + if (l2 == null) { + break; + } + // It is possible that a Level2Entry e1 for the OID/type pair + // (o,t) becomes weakly reachable, then another Level2Entry e2 + // is registered for the same pair (o,t) (a new Level2Entry is + // created since now e1.get() == null), and only then e1 is + // enqueued. To not erroneously remove the new e2 in that case, + // check whether the map still contains e1: + Level1Entry l1 = level1map.get(l2.oid); + if (l1 != null && l1.level2map.get(l2.type) == l2) { + removeLevel2Entry(l1, l2.oid, l2.type); + } + } + } + + // must only be called while synchronized on this Registry: + private void removeLevel2Entry(Level1Entry l1, String oid, Type type) { + l1.level2map.remove(type); + if (l1.level2map.isEmpty()) { + level1map.remove(oid); + } + } + + private static final class Level1Entry { + // must only be called while synchronized on enclosing Registry: + public Object find(Type type) { + // First, look for an exactly matching entry; then, look for an + // arbitrary entry for a subtype of the request type: + Level2Entry l2 = level2map.get(type); + if (l2 != null) { + Object o = l2.get(); + if (o != null) { + return o; + } + } + for (Iterator<Level2Entry> i = level2map.values().iterator(); + i.hasNext();) + { + l2 = i.next(); + if (type.isSupertypeOf(l2.type)) { + Object o = l2.get(); + if (o != null) { + return o; + } + } + } + return null; + } + + public final HashMap<Type, Level2Entry> level2map = + new HashMap<Type, Level2Entry>(); + } + + private static final class Level2Entry extends WeakReference<Object> { + public Level2Entry( + String oid, Type type, Object object, ReferenceQueue queue) + { + super(object, queue); + this.oid = oid; + this.type = type; + } + + // must only be called while synchronized on enclosing Registry: + public void acquire() { + ++count; + } + + // must only be called while synchronized on enclosing Registry: + public boolean release() { + return --count == 0; + } + + public final String oid; + public final Type type; + + private int count = 1; + } + + private final HashMap<String, Level1Entry> level1map = + new HashMap<String, Level1Entry>(); + private final ReferenceQueue queue = new ReferenceQueue(); + } + + private boolean isProxy(Object object) { + return object instanceof com.sun.star.lib.uno.Proxy; + } + + private static final Registry localObjects = new Registry(); + + private final Object context; + private final Registry proxies = new Registry(); +} |