| /* ObjID.java -- Unique object id with respect to the given host. |
| Copyright (c) 1996, 1997, 1998, 1999, 2004, 2006 |
| 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 |
| the Free Software Foundation; either version 2, or (at your option) |
| 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 |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| 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 |
| conditions of the GNU General Public License cover the whole |
| 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 |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package java.rmi.server; |
| |
| import java.io.DataInput; |
| import java.io.DataOutput; |
| import java.io.IOException; |
| import java.io.ObjectInput; |
| import java.io.ObjectOutput; |
| import java.io.Serializable; |
| |
| /** |
| * Represents the object identifier, unique for the host that generated it. |
| * The ObjID contains inside the integer object identifier that, if needed, |
| * may indicated that this is a reference to one of the well known objects |
| * on that host (registry, activator or dgc) and the {@link UID} that |
| * ensures uniqueness. |
| */ |
| public final class ObjID |
| implements Serializable |
| { |
| |
| /** |
| * Use serial version uid for interoperability. |
| */ |
| static final long serialVersionUID = - 6386392263968365220L; |
| |
| /** |
| * The object counter, which value is assigned when creating the ordinary |
| * objects without the known object id. The counter is incremented each time |
| * the new ObjID is constructed. |
| */ |
| private static long next = 0x8000000000000000L; |
| |
| /** |
| * The object to put the lock on when incrementing {@link #next} |
| */ |
| private static final Object lock = ObjID.class; |
| |
| /** |
| * Defines the ID of the naming service. |
| */ |
| public static final int REGISTRY_ID = 0; |
| |
| /** |
| * Defines the ID of the activator. |
| */ |
| public static final int ACTIVATOR_ID = 1; |
| |
| /** |
| * Defines the ID of the distributed garbage collector. |
| */ |
| public static final int DGC_ID = 2; |
| |
| /** |
| * The object Id (either well-known value or the value of the incrementing |
| * object counter. |
| */ |
| long objNum; |
| |
| /** |
| * The object unique identifier, generated individually for each object. |
| */ |
| UID space; |
| |
| /** |
| * Create the new object id, unique for this host. |
| */ |
| public ObjID() |
| { |
| synchronized (lock) |
| { |
| objNum = next++; |
| } |
| space = new UID(); |
| } |
| |
| /** |
| * Create the new object id defining the well known remotely accessible |
| * object, present in this host. The well - known objects are: |
| * <ul> |
| * <li>{@link #REGISTRY_ID} - RMI naming service.</li> |
| * <li>{@link #ACTIVATOR_ID} - activator</li> |
| * <li>{@link #DGC_ID} - distributed garbage collector (grants lease |
| * durations to keep the object before it is garbage collected.</li> |
| * </ul> |
| * |
| * @param id the well known object id, one of the above. |
| */ |
| public ObjID(int id) |
| { |
| objNum = (long) id; |
| space = new UID((short) 0); |
| } |
| |
| /** |
| * Write object id as long, then the object {@link UID}. |
| */ |
| public void write(ObjectOutput out) throws IOException |
| { |
| DataOutput dout = (DataOutput) out; |
| dout.writeLong(objNum); |
| space.write(dout); |
| } |
| |
| /** |
| * Read object id (as long), then the object {@link UID}. |
| */ |
| public static ObjID read(ObjectInput in) throws IOException |
| { |
| DataInput din = (DataInput) in; |
| ObjID id = new ObjID(); |
| id.objNum = din.readLong(); |
| id.space = UID.read(din); |
| return (id); |
| } |
| |
| /** |
| * Get the hashcode. |
| */ |
| public int hashCode() |
| { |
| return space == null ? (int) objNum : space.hashCode() ^ (int) objNum; |
| } |
| |
| /** |
| * Compare for equality. |
| */ |
| public boolean equals(Object obj) |
| { |
| if (obj instanceof ObjID) |
| { |
| ObjID that = (ObjID) obj; |
| return that.objNum == objNum && eq(that.space, space); |
| } |
| else |
| return false; |
| } |
| |
| /** |
| * Compare by .equals if both a and b are not null, compare directly if at |
| * least one of them is null. |
| */ |
| static final boolean eq(Object a, Object b) |
| { |
| if (a == null || b == null) |
| return a == b; |
| else |
| return a.equals(b); |
| } |
| |
| /** |
| * Get the string representation. |
| */ |
| public String toString() |
| { |
| return (objNum + ":" + space); |
| } |
| |
| } |