From 6b67de9fcac98c4d0166b1e9ef4371a718a85818 Mon Sep 17 00:00:00 2001
From: Michael Bayne <mdb@threerings.net>
Date: Tue, 17 Jul 2007 22:03:12 +0000
Subject: [PATCH] Looking something up in all the peer node objects is tricky,
 so let's encapsulate it into a mechanism that takes care of the trickiness
 for us.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@4770 542714f4-19e9-0310-aa3c-eee0fc999fb1
---
 .../presents/peer/server/PeerManager.java     | 29 +++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/src/java/com/threerings/presents/peer/server/PeerManager.java b/src/java/com/threerings/presents/peer/server/PeerManager.java
index a21b5590d..c0f8d35b7 100644
--- a/src/java/com/threerings/presents/peer/server/PeerManager.java
+++ b/src/java/com/threerings/presents/peer/server/PeerManager.java
@@ -97,6 +97,12 @@ public class PeerManager
         public void droppedLock (NodeObject.Lock lock);
     }
 
+    /** Used by {@link #lookupNodeDatum}. */
+    public static interface Lookup<T>
+    {
+        public T lookup (NodeObject nodeobj);
+    }
+
     /**
      * Creates a peer manager which will create a {@link NodeRepository} which will be used to
      * publish our existence and discover the other nodes.
@@ -216,6 +222,29 @@ public class PeerManager
         }
     }
 
+    /**
+     * Locates a datum from among the set of peer {@link NodeObject}s. Objects are searched in
+     * arbitrary order and the first non-null value returned by the supplied lookup operation is
+     * returned to the caller. Null if all lookup operations returned null.
+     */
+    public <T> T lookupNodeDatum (Lookup<T> op)
+    {
+        T value = op.lookup(_nodeobj);
+        if (value != null) {
+            return value;
+        }
+        for (PeerNode peer : _peers.values()) {
+            if (peer.nodeobj == null) {
+                continue;
+            }
+            value = op.lookup(peer.nodeobj);
+            if (value != null) {
+                return value;
+            }
+        }
+        return value;
+    }
+
     /**
      * Returns true if the supplied peer credentials match our shared secret.
      */