/* UnicastServer.java --
Copyright (c) 1996, 1997, 1998, 1999, 2002, 2004
Free Software Foundation, Inc.
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
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any later version.
GNU Classpath 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 for more details.
You should have received a copy of the GNU General Public License
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
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combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
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this exception to your version of the library, but you are not
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exception statement from your version. */
package gnu.java.rmi.server;
import gnu.java.rmi.dgc.DGCImpl;
import gnu.java.util.WeakIdentityHashMap;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.rmi.NoSuchObjectException;
import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.ServerError;
import java.rmi.activation.ActivationException;
import java.rmi.activation.ActivationID;
import java.rmi.server.ObjID;
import java.rmi.server.UID;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Map;
import java.util.WeakHashMap;
public class UnicastServer
implements ProtocolConstants
{
/**
* Mapping OBJID to server ref by .equals().
*/
static private Map objects = Collections.synchronizedMap(new WeakHashMap());
/**
* Mapping obj itself to server ref by identity.
*/
static private Map refcache = Collections.synchronizedMap(new WeakIdentityHashMap());
/**
* Mapping the registered activatable objects into they server references.
*/
public static Map actIds = new Hashtable();
/**
* The reference to the local distributed garbage collector.
*/
static private DGCImpl dgc;
/**
* Connect this server reference to the server, allowing the local
* implementation, associated with this object, to receive remote calls.
*
* @param obj the server reference, encloses the (usually local) remote
* object.
*/
public static void exportObject(UnicastServerRef obj)
{
startDGC();
objects.put(obj.objid, obj);
refcache.put(obj.myself, obj);
obj.manager.startServer();
}
/**
* Register the activatable object into the table of the activatable
* objects.
*/
public static void registerActivatable(ActivatableServerRef ref)
{
actIds.put(ref.actId, ref);
}
/**
* Export tha activatable object. The object id is placed into the map,
* but the object itself not. This is enough to deliver call to
* the ref.incomingMessageCall where the object will be instantiated,
* if not present.
*/
public static void exportActivatableObject(ActivatableServerRef ref)
{
startDGC();
objects.put(ref.objid, ref);
ref.manager.startServer();
actIds.put(ref.actId, ref);
}
/**
* Get the activatable server reference that is handling activation of the
* given activation id.
*/
public static ActivatableServerRef getActivatableRef(ActivationID id)
throws ActivationException
{
ActivatableServerRef ref = (ActivatableServerRef) actIds.get(id);
if (ref == null)
throw new ActivationException(id + " was not registered with this server");
return ref;
}
/**
* Unregister the previously registered activatable server reference.
*/
public static void unregisterActivatable(ActivationID id)
{
actIds.remove(id);
}
// FIX ME: I haven't handle force parameter
/**
* Remove the given server reference. The remote object, associated with
* this reference, will no longer receive remote calls via this server.
*/
public static boolean unexportObject(UnicastServerRef obj, boolean force)
{
objects.remove(obj.objid);
refcache.remove(obj.myself);
obj.manager.stopServer();
if (obj instanceof ActivatableServerRef)
{
ActivationID id = ((ActivatableServerRef) obj).actId;
unregisterActivatable(id);
}
return true;
}
/**
* Get the exported reference of the given Remote. The identity map is used,
* the non-null value will only be returned if exactly the passed remote
* is part of the registered UnicastServerRef.
*
* @param remote the Remote that is connected to this server via
* {@link UnicastServerRef}.
*
* @return the UnicastServerRef that is used to connect the passed
* remote with this server or null, if this Remote is not connected
* to this server.
*/
public static UnicastServerRef getExportedRef(Remote remote)
{
return (UnicastServerRef) refcache.get(remote);
}
/**
* Get the server references to the object, previously exported via this
* server. As the identity map is scanned, more than one reference may match
* this Id.
*
* @param id the id of the exported object
* @return the server reference to this object, null if none.
*/
public static Collection getExported(Object id)
{
synchronized (objects)
{
ArrayList list = new ArrayList();
Iterator iter = objects.entrySet().iterator();
Map.Entry e;
Object key;
while (iter.hasNext())
{
e = (Map.Entry) iter.next();
key = e.getKey();
if (key != null && key.equals(id))
list.add(e.getValue());
}
return list;
}
}
private static synchronized void startDGC()
{
if (dgc == null)
{
try
{
dgc = new DGCImpl();
// Changed DGCImpl to inherit UnicastServerRef directly
// ((UnicastServerRef)dgc.getRef()).exportObject(dgc);
dgc.exportObject(dgc);
}
catch (RemoteException e)
{
e.printStackTrace();
}
}
}
public static void dispatch(UnicastConnection conn) throws Exception
{
switch (conn.getDataInputStream().readUnsignedByte())
{
case MESSAGE_CALL:
incomingMessageCall(conn);
break;
case MESSAGE_PING:
// jdk sends a ping before each method call -> answer it!
DataOutputStream out = conn.getDataOutputStream();
out.writeByte(MESSAGE_PING_ACK);
out.flush();
break;
default:
throw new Exception("bad method type");
}
}
/**
* This method is invoked when the remote call is received. The method
* dispatches the call to the responsible object, connected to this
* server via UnicastServerReference.
*/
private static void incomingMessageCall(UnicastConnection conn)
throws IOException
{
ObjectInputStream in = conn.startObjectInputStream(); // (re)start
// ObjectInputStream
ObjID objid = ObjID.read(in);
int method = in.readInt();
long hash = in.readLong();
// System.out.println("ObjID: " + objid + ", method: " + method + ", hash: "
// + hash);
// Use the objid to locate the relevant UnicastServerRef
UnicastServerRef uref = (UnicastServerRef) objects.get(objid);
Object returnval;
int returncode = RETURN_ACK;
// returnval is from Method.invoke(), so we must check the return class to
// see
// if it's primitive type
Class returncls = null;
if (uref != null)
{
try
{
// Dispatch the call to it.
returnval = uref.incomingMessageCall(conn, method, hash);
returncls = uref.getMethodReturnType(method, hash);
}
catch (Exception e)
{
returnval = e;
returncode = RETURN_NACK;
}
catch (Error e)
{
returnval = new ServerError(
"Server error, ObjID: " + objid +
", method: " + method + ", hash: "+ hash, e);
returncode = RETURN_NACK;
}
}
else
{
returnval = new NoSuchObjectException("ObjID: " + objid);
returncode = RETURN_NACK;
}
conn.getDataOutputStream().writeByte(MESSAGE_CALL_ACK);
ObjectOutputStream out = conn.startObjectOutputStream(); // (re)start
// ObjectOutputStream
out.writeByte(returncode);
(new UID()).write(out);
// System.out.println("returnval=" + returnval + " returncls=" + returncls);
if (returnval != null && returncls != null)
((RMIObjectOutputStream) out).writeValue(returnval, returncls);
// 1.1/1.2 void return type detection:
else if (! (returnval instanceof RMIVoidValue || returncls == Void.TYPE))
out.writeObject(returnval);
out.flush();
}
}