More progress on the distributed object stuff.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@19 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/presents/dobj/AttributeChangedEvent.java

@@ -1,8 +1,11 @@
 //
-// $Id: AttributeChangedEvent.java,v 1.1 2001/06/01 07:12:13 mdb Exp $
+// $Id: AttributeChangedEvent.java,v 1.2 2001/06/01 19:56:13 mdb Exp $
 
 package com.threerings.cocktail.cher.dobj;
 
+import java.lang.reflect.Method;
+import com.threerings.cocktail.cher.Log;
+
 /**
  * An attribute changed event is dispatched when a single attribute of a
  * distributed object has changed. It can also be constructed to request
@@ -92,6 +95,24 @@ public class AttributeChangedEvent extends DEvent
         return ((Double)_value).doubleValue();
     }
 
+    /**
+     * Applies this attribute change to the object.
+     */
+    public boolean applyToObject (DObject target)
+        throws ObjectAccessException
+    {
+        // look up the setter for this object
+        Method setter = DEventUtil.getSetter(target.getClass(), _name);
+
+        try {
+            setter.invoke(target, new Object[] { _value });
+        } catch (Exception e) {
+            throw new ObjectAccessException("Reflection error: " + e);
+        }
+
+        return true;
+    }
+
     protected String _name;
     protected Object _value;
 }

src/java/com/threerings/presents/dobj/DEvent.java

@@ -1,5 +1,5 @@
 //
-// $Id: DEvent.java,v 1.2 2001/06/01 07:12:13 mdb Exp $
+// $Id: DEvent.java,v 1.3 2001/06/01 19:56:13 mdb Exp $
 
 package com.threerings.cocktail.cher.dobj;
 
@@ -9,7 +9,7 @@ package com.threerings.cocktail.cher.dobj;
  * notification purposes, without making any modifications to the object
  * that defines the delivery group (the object's subscribers).
  */
-public class DEvent
+public abstract class DEvent
 {
     /**
      * Returns the oid of the object that is the target of this event.
@@ -19,6 +19,22 @@ public class DEvent
         return _toid;
     }
 
+    /**
+     * Applies the attribute modifications represented by this event to
+     * the specified target object. This is called by the distributed
+     * object manager in the course of dispatching events and should not
+     * be called directly.
+     *
+     * @exception ObjectAccessException thrown if there is any problem
+     * applying the event to the object (invalid attribute, etc.).
+     *
+     * @return true if the object manager should go on to notify the
+     * object's subscribers of this event, false if the event should be
+     * treated silently and the subscribers should not be notified.
+     */
+    public abstract boolean applyToObject (DObject target)
+        throws ObjectAccessException;
+
     /**
      * Constructs a new distributed object event that pertains to the
      * specified distributed object.

src/java/com/threerings/presents/dobj/DEventUtil.java

@@ -0,0 +1,66 @@
+//
+// $Id: DEventUtil.java,v 1.1 2001/06/01 19:56:13 mdb Exp $
+
+package com.threerings.cocktail.cher.dobj;
+
+import java.lang.reflect.Method;
+import java.util.HashMap;
+
+/**
+ * A repository for distributed object event related utility functions.
+ */
+public class DEventUtil
+{
+    /**
+     * Looks up and returns the method used to set an attribute of the
+     * specified name on an instance of the specified distributed object
+     * class.
+     */
+    public static Method getSetter (Class clazz, String name)
+        throws ObjectAccessException
+    {
+        // first see if it's cached
+        Method setter = (Method)_setterCache.get(name);
+        if (setter != null) {
+            return setter;
+        }
+
+        // convert the attribute name into a setter name
+        String sname = setterName(name);
+        try {
+            // look up that method (we don't have the parameter types, so
+            // we have to do our own name matching)
+            Method[] methods = clazz.getMethods();
+            for (int i = 0; i < methods.length; i++) {
+                if (methods[i].getName().equals(sname)) {
+                    setter = methods[i];
+                    break;
+                }
+            }
+
+        } catch (SecurityException se) {
+            throw new ObjectAccessException("Reflection error: " + se);
+        }
+
+        // make sure we found a matching method
+        if (setter == null) {
+            String errmsg = "No setter for attribute '" + name + "'.";
+            throw new ObjectAccessException(errmsg);
+        }
+
+        // and cache it
+        _setterCache.put(name, setter);
+        return setter;
+    }
+
+    protected static String setterName (String name)
+    {
+        StringBuffer sname = new StringBuffer();
+        sname.append("get");
+        sname.append(Character.toUpperCase(name.charAt(0)));
+        sname.append(name.substring(1));
+        return sname.toString();
+    }
+
+    protected static HashMap _setterCache = new HashMap();
+}

src/java/com/threerings/presents/dobj/DObject.java

@@ -1,5 +1,5 @@
 //
-// $Id: DObject.java,v 1.6 2001/06/01 05:17:16 mdb Exp $
+// $Id: DObject.java,v 1.7 2001/06/01 19:56:13 mdb Exp $
 
 package com.threerings.cocktail.cher.dobj;
 
@@ -73,17 +73,17 @@ import java.util.ArrayList;
 public class DObject
 {
     /**
-     * Constructs a new distributed object with the supplied object id.
-     * This should not be called directly, rather objects should be
-     * created via the distributed object manager.
+     * Initializes this distributed object with the supplied object id and
+     * distributed object manager. This is called by the distributed
+     * object manager when an object is created and registered with the
+     * system. Don't call this function yourself.
      *
      * @see DObjectManager.createObject
      */
-    public DObject (int oid, DObjectManager manager)
+    public void init (int oid, DObjectManager mgr)
     {
         _oid = oid;
-        _mgr = manager;
-        _subscribers = new ArrayList();
+        _mgr = mgr;
     }
 
     /**
@@ -106,10 +106,10 @@ public class DObject
      * <p> If the specified subscriber is already subscribed to this
      * object, they will not be added to the list a second time.
      */
-    public void addSubscriber (Subscriber subscriber)
+    public void addSubscriber (Subscriber sub)
     {
-        if (!_subscribers.contains(subscriber)) {
-            _subscribers.add(subscriber);
+        if (!_subscribers.contains(sub)) {
+            _subscribers.add(sub);
         }
     }
 
@@ -121,12 +121,66 @@ public class DObject
      * subscriber is not currently on the list of subscribers for this
      * object, nothing happens.
      */
-    public void removeSubscriber (Subscriber subscriber)
+    public void removeSubscriber (Subscriber sub)
     {
-        _subscribers.remove(subscriber);
+        _subscribers.remove(sub);
+    }
+
+    /**
+     * Checks to ensure that the specified subscriber has access to this
+     * object. This will be called before satisfying any fetch or
+     * subscription request. By default objects are accessible to all
+     * subscriber, but certain objects may wish to implement more fine
+     * grained access control.
+     *
+     * @param sub the subscriber that will fetch or subscribe to this
+     * object.
+     *
+     * @return true if the subscriber has access to the object, false if
+     * they do not.
+     */
+    public boolean checkPermissions (Subscriber sub)
+    {
+        return true;
+    }
+
+    /**
+     * Checks to ensure that this event which is about to be processed,
+     * has the appropriate permissions. By default objects accept all
+     * manner of events, but certain objects may wish to implement more
+     * fine grained access control.
+     *
+     * @param event the event that will be dispatched, object permitting.
+     *
+     * @return true if the event is valid and should be dispatched, false
+     * if the event fails the permissions check and should be aborted.
+     */
+    public boolean checkPermissions (DEvent event)
+    {
+        return true;
+    }
+
+    /**
+     * Called by the distributed object manager after it has applied an
+     * event to this object. This dispatches an event notification to all
+     * of the subscribers of this object.
+     *
+     * @param event the event that was just applied.
+     */
+    public void notifySubscribers (DEvent event)
+    {
+        for (int i = 0; i < _subscribers.size(); i++) {
+            Subscriber sub = (Subscriber)_subscribers.get(i);
+            // notify the subscriber
+            if (!sub.handleEvent(event, this)) {
+                // if they return false, we need to remove them from the
+                // subscriber list
+                _subscribers.remove(i--);
+            }
+        }
     }
 
     protected int _oid;
     protected DObjectManager _mgr;
-    protected ArrayList _subscribers;
+    protected ArrayList _subscribers = new ArrayList();
 }