Added #canProbePresence(JID prober, String probee). JM-234

git-svn-id: http://svn.igniterealtime.org/svn/repos/messenger/trunk@1661 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/messenger/PresenceManager.java

@@ -12,6 +12,7 @@
 package org.jivesoftware.messenger;
 
 import org.jivesoftware.messenger.user.User;
+import org.jivesoftware.messenger.user.UserNotFoundException;
 import org.jivesoftware.messenger.auth.UnauthorizedException;
 import org.xmpp.packet.Presence;
 import org.xmpp.packet.JID;
@@ -82,6 +83,17 @@ public interface PresenceManager {
      */
     public void handleProbe(Presence packet) throws UnauthorizedException;
 
+    /**
+     * Returns true if the the prober is allowed to see the presence of the probee.
+     *
+     * @param prober the user that is trying to probe the presence of another user.
+     * @param probee the username of the uset that is being probed.
+     * @return true if the the prober is allowed to see the presence of the probee.
+     * @throws UserNotFoundException If the probee does not exist in the local server or the prober
+     *         is not present in the roster of the probee.
+     */
+    public boolean canProbePresence(JID prober, String probee) throws UserNotFoundException;
+
     /**
      * Sends unavailable presence from all of the user's available resources to the remote user.
      * When a remote user unsubscribes from the presence of a local user then the server should

src/java/org/jivesoftware/messenger/spi/PresenceManagerImpl.java

@@ -219,6 +219,29 @@ public class PresenceManagerImpl extends BasicModule implements PresenceManager
         }
     }
 
+    public boolean canProbePresence(JID prober, String probee) throws UserNotFoundException {
+        // Check that the probee is a valid user
+        UserManager.getInstance().getUser(probee);
+        // Check for a cached roster:
+        Roster roster = (Roster)CacheManager.getCache("username2roster").get(probee);
+        if (roster == null) {
+            synchronized(probee.intern()) {
+                roster = (Roster)CacheManager.getCache("username2roster").get(probee);
+                if (roster == null) {
+                    // Not in cache so load a new one:
+                    roster = new Roster(probee);
+                    CacheManager.getCache("username2roster").put(probee, roster);
+                }
+            }
+        }
+        RosterItem item = roster.getRosterItem(prober);
+        if (item.getSubStatus() == RosterItem.SUB_FROM
+                || item.getSubStatus() == RosterItem.SUB_BOTH) {
+            return true;
+        }
+        return false;
+    }
+
     public void probePresence(JID prober, JID probee) {
         try {
             Component component = getPresenceComponent(probee);