From 76ba2840c43a1d2918b8c7434b7e5ff0c6a931b6 Mon Sep 17 00:00:00 2001
From: Michael Bayne <mdb@threerings.net>
Date: Sun, 27 Oct 2002 01:33:43 +0000
Subject: [PATCH] Provide access to the values that existed previous to the
 application of events that change values.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@1837 542714f4-19e9-0310-aa3c-eee0fc999fb1
---
 .../presents/dobj/AttributeChangedEvent.java      | 14 +++++++++++++-
 .../presents/dobj/ElementUpdatedEvent.java        | 15 ++++++++++++++-
 .../presents/dobj/EntryUpdatedEvent.java          | 14 +++++++++++++-
 3 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/src/java/com/threerings/presents/dobj/AttributeChangedEvent.java b/src/java/com/threerings/presents/dobj/AttributeChangedEvent.java
index ee98596ca..102ae2b9e 100644
--- a/src/java/com/threerings/presents/dobj/AttributeChangedEvent.java
+++ b/src/java/com/threerings/presents/dobj/AttributeChangedEvent.java
@@ -1,5 +1,5 @@
 //
-// $Id: AttributeChangedEvent.java,v 1.12 2002/07/23 05:52:48 mdb Exp $
+// $Id: AttributeChangedEvent.java,v 1.13 2002/10/27 01:33:43 mdb Exp $
 
 package com.threerings.presents.dobj;
 
@@ -63,6 +63,15 @@ public class AttributeChangedEvent extends DEvent
         return _value;
     }
 
+    /**
+     * Returns the value of the attribute prior to the application of this
+     * event.
+     */
+    public Object getOldValue ()
+    {
+        return _oldValue;
+    }
+
     /**
      * Returns the new value of the attribute as a short. This will fail
      * if the attribute in question is not a short.
@@ -114,6 +123,8 @@ public class AttributeChangedEvent extends DEvent
     public boolean applyToObject (DObject target)
         throws ObjectAccessException
     {
+        // grab the previous value
+        _oldValue = target.getAttribute(_name);
         // pass the new value on to the object
         target.setAttribute(_name, _value);
         return true;
@@ -161,4 +172,5 @@ public class AttributeChangedEvent extends DEvent
 
     protected String _name;
     protected Object _value;
+    protected transient Object _oldValue;
 }
diff --git a/src/java/com/threerings/presents/dobj/ElementUpdatedEvent.java b/src/java/com/threerings/presents/dobj/ElementUpdatedEvent.java
index 68fdfb350..8230479ae 100644
--- a/src/java/com/threerings/presents/dobj/ElementUpdatedEvent.java
+++ b/src/java/com/threerings/presents/dobj/ElementUpdatedEvent.java
@@ -1,5 +1,5 @@
 //
-// $Id: ElementUpdatedEvent.java,v 1.2 2002/07/23 05:52:48 mdb Exp $
+// $Id: ElementUpdatedEvent.java,v 1.3 2002/10/27 01:33:43 mdb Exp $
 
 package com.threerings.presents.dobj;
 
@@ -68,6 +68,15 @@ public class ElementUpdatedEvent extends DEvent
         return _value;
     }
 
+    /**
+     * Returns the value of the element prior to the application of this
+     * event.
+     */
+    public Object getOldValue ()
+    {
+        return _oldValue;
+    }
+
     /**
      * Returns the index of the element.
      */
@@ -138,6 +147,9 @@ public class ElementUpdatedEvent extends DEvent
                 throw new Exception(msg);
             }
 
+            // grab the previous value to provide to interested parties
+            _oldValue = Array.get(field.get(target), _index);
+
             // we don't do any magical expansion or any funny business;
             // the array should be big enough to contain the value being
             // updated or we'll throw an ArrayIndexOutOfBoundsException
@@ -197,4 +209,5 @@ public class ElementUpdatedEvent extends DEvent
     protected String _name;
     protected Object _value;
     protected int _index;
+    protected transient Object _oldValue;
 }
diff --git a/src/java/com/threerings/presents/dobj/EntryUpdatedEvent.java b/src/java/com/threerings/presents/dobj/EntryUpdatedEvent.java
index 2f9f2fafd..141e10021 100644
--- a/src/java/com/threerings/presents/dobj/EntryUpdatedEvent.java
+++ b/src/java/com/threerings/presents/dobj/EntryUpdatedEvent.java
@@ -1,5 +1,5 @@
 //
-// $Id: EntryUpdatedEvent.java,v 1.7 2002/07/23 05:52:48 mdb Exp $
+// $Id: EntryUpdatedEvent.java,v 1.8 2002/10/27 01:33:43 mdb Exp $
 
 package com.threerings.presents.dobj;
 
@@ -63,6 +63,14 @@ public class EntryUpdatedEvent extends DEvent
         return _entry;
     }
 
+    /**
+     * Returns the entry that was in the set prior to being updated.
+     */
+    public DSet.Entry getOldEntry ()
+    {
+        return _oldEntry;
+    }
+
     /**
      * Applies this event to the object.
      */
@@ -71,6 +79,9 @@ public class EntryUpdatedEvent extends DEvent
     {
         DSet set = (DSet)target.getAttribute(_name);
 
+        // fetch the previous value for interested callers
+        _oldEntry = set.get(_entry.getKey());
+
         // update the entry
         if (!set.update(_entry)) {
             // complain if we didn't update anything
@@ -124,4 +135,5 @@ public class EntryUpdatedEvent extends DEvent
 
     protected String _name;
     protected DSet.Entry _entry;
+    protected transient DSet.Entry _oldEntry;
 }