These classes are undocumented in our project. Before working with the code I wrote some comments and applied Eclipse formatter.

2006-03-03  Audrius Meskauskas  <AudriusA@Bioinformatics.org>

    * gnu/java/rmi/dgc/DGCImpl.java,
    java/rmi/dgc/DGC.java,
    java/rmi/dgc/Lease.java: Formatted and commented.

2 files changed, 116 insertions, 54 deletions

diff --git a/java/rmi/dgc/DGC.java b/java/rmi/dgc/DGC.java
index e78ec2a3a..66bfc6dfd 100644
--- a/java/rmi/dgc/DGC.java
+++ b/java/rmi/dgc/DGC.java
@@ -41,11 +41,40 @@ import java.rmi.Remote;
 import java.rmi.RemoteException;
 import java.rmi.server.ObjID;
 
-public interface DGC extends Remote
+/**
+ * The DGC implementation is used for the server side during the distributed
+ * garbage collection. This interface contains the two methods: dirty and clean.
+ * A dirty call is made when a remote reference is unmarshaled in a client. A
+ * corresponding clean call is made by client it no longer uses that remote
+ * reference. A reference to a remote object is also automatically released
+ * after so called lease period that starts after the dirty call is received. It
+ * is the client's responsibility to renew the leases, by making additional
+ * dirty calls before such leases expire.
+ */
+public interface DGC
+    extends Remote
 {
-  Lease dirty (ObjID[] ids, long sequenceNum, Lease lease)
-    throws RemoteException;
+  /**
+   * Mark the given objects referecnes as used on the client side.
+   * 
+   * @param ids the ids of the used objects.
+   * @param sequenceNum the number of the call (used to detect and discard late
+   *          calls).
+   * @param lease the requested lease
+   * @return the granted lease
+   */
+  Lease dirty(ObjID[] ids, long sequenceNum, Lease lease)
+      throws RemoteException;
 
-  void clean (ObjID[] ids, long sequenceNum, VMID vmid, boolean strong)
-    throws RemoteException;
+  /**
+   * Mark the given objects as no longer used on the client side.
+   * 
+   * @param ids the ids of the objects that are no longer used.
+   * @param sequenceNum the number of the call (used to detect and discard late
+   * @param vmid the VMID of the client.
+   * @param strong make the "strong" clean call ("strong" calls are scheduled
+   * after the failed dirty calls).
+   */
+  void clean(ObjID[] ids, long sequenceNum, VMID vmid, boolean strong)
+      throws RemoteException;
 }
diff --git a/java/rmi/dgc/Lease.java b/java/rmi/dgc/Lease.java
index d3d7f6952..7f53fe3fd 100644
--- a/java/rmi/dgc/Lease.java
+++ b/java/rmi/dgc/Lease.java
@@ -1,67 +1,100 @@
 /* Lease.java
-   Copyright (c) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
+ Copyright (c) 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
 
-This file is part of GNU Classpath.
+ 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 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. */
+ 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.dgc;
 
 import java.io.Serializable;
 
+/**
+ * A lease object is used to request and grant leases for the remote objects. It
+ * contains the lease duration and the unique VM indentifier.
+ */
 public final class Lease
-	implements Serializable {
+    implements Serializable
+{
 
-static final long serialVersionUID = -5713411624328831948L;
+  static final long serialVersionUID = - 5713411624328831948L;
 
-private VMID vmid;
-private long value;
+  private VMID vmid;
 
-public Lease(VMID id, long duration) {
-	vmid = id;
-	value = duration;
-}
+  private long value;
 
-public VMID getVMID() {
-	return (vmid);
-}
+  /**
+   * Create the new lease with the given id and duration
+   * 
+   * @param id the lease id
+   * @param duration the lease duration
+   */
+  public Lease(VMID id, long duration)
+  {
+    vmid = id;
+    value = duration;
+  }
 
-public long getValue() {
-	return (value);
-}
+  /**
+   * Get the lease id.
+   * 
+   * @return the lease id
+   */
+  public VMID getVMID()
+  {
+    return (vmid);
+  }
 
-public String toString() {
-	return ("[" + vmid.toString() + ", " + Long.toString(value) + "]");
-}
+  /**
+   * Get the lease duration
+   * 
+   * @return the lease duration
+   */
+  public long getValue()
+  {
+    return (value);
+  }
+
+  /**
+   * Get the string representation of this lease
+   * 
+   * @return the string represenation (lease id, followed by the lease
+   *         duration).
+   */
+  public String toString()
+  {
+    return ("[" + vmid.toString() + ", " + Long.toString(value) + "]");
+  }
 
 }