From 047dd3b8717903d1ac2f0f780b65f418137f7888 Mon Sep 17 00:00:00 2001
From: Michael Bayne <mdb@threerings.net>
Date: Mon, 13 Jul 2009 00:55:03 +0000
Subject: [PATCH] Sprinkled some functional programming onto node object
 handling.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5868 542714f4-19e9-0310-aa3c-eee0fc999fb1
---
 .../presents/peer/server/PeerManager.java     | 60 ++++++++++---------
 1 file changed, 31 insertions(+), 29 deletions(-)

diff --git a/src/java/com/threerings/presents/peer/server/PeerManager.java b/src/java/com/threerings/presents/peer/server/PeerManager.java
index 2b3be9411..dfde183d7 100644
--- a/src/java/com/threerings/presents/peer/server/PeerManager.java
+++ b/src/java/com/threerings/presents/peer/server/PeerManager.java
@@ -21,6 +21,7 @@
 
 package com.threerings.presents.peer.server;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.atomic.AtomicLong;
@@ -29,6 +30,9 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 
 import com.google.common.base.Function;
+import com.google.common.base.Predicates;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.inject.Inject;
 import com.google.inject.Injector;
@@ -214,6 +218,17 @@ public abstract class PeerManager
         return _nodeobj;
     }
 
+    /**
+     * Returns an iterable over our node object and that of our peers.
+     */
+    public Iterable<NodeObject> getNodeObjects ()
+    {
+        return Iterables.filter(
+            Iterables.concat(Collections.singleton(_nodeobj),
+                             Iterables.transform(_peers.values(), GET_NODE_OBJECT)),
+            Predicates.notNull());
+    }
+
     /**
      * Initializes this peer manager and initiates the process of connecting to its peer nodes.
      * This will also reconfigure the ConnectionManager and ClientManager with peer related bits,
@@ -302,35 +317,20 @@ public abstract class PeerManager
      */
     public <T> T lookupNodeDatum (Function<NodeObject,T> op)
     {
-        T value = op.apply(_nodeobj);
-        if (value != null) {
+        for (T value : Iterables.transform(getNodeObjects(), op)) {
             return value;
         }
-        for (PeerNode peer : _peers.values()) {
-            if (peer.nodeobj == null) {
-                continue;
-            }
-            value = op.apply(peer.nodeobj);
-            if (value != null) {
-                return value;
-            }
-        }
-        return value;
+        return null;
     }
 
     /**
-     * Applies the supplied operation to all {@link NodeObject}s. The operation should not modify
+     * Applies the supplied function to all {@link NodeObject}s. The operation should not modify
      * the objects unless you really know what you're doing. More likely it will summarize
      * information contained therein.
      */
-    public void applyToNodes (Function<NodeObject,Void> op)
+    public <T> Iterable<T> applyToNodes (Function<NodeObject,T> op)
     {
-        op.apply(_nodeobj);
-        for (PeerNode peer : _peers.values()) {
-            if (peer.nodeobj != null) {
-                op.apply(peer.nodeobj);
-            }
-        }
+        return Iterables.transform(getNodeObjects(), op);
     }
 
     /**
@@ -650,15 +650,9 @@ public abstract class PeerManager
      */
     public String queryLock (NodeObject.Lock lock)
     {
-        // look for it in our own lock set
-        if (_nodeobj.locks.contains(lock)) {
-            return _nodeName;
-        }
-
-        // then in our peers
-        for (PeerNode peer : _peers.values()) {
-            if (peer.nodeobj != null && peer.nodeobj.locks.contains(lock)) {
-                return peer.getNodeName();
+        for (NodeObject nodeobj : getNodeObjects()) {
+            if (nodeobj.locks.contains(lock)) {
+                return nodeobj.nodeName;
             }
         }
         return null;
@@ -1380,6 +1374,14 @@ public abstract class PeerManager
         protected long _startStamp = System.currentTimeMillis();
     }
 
+    /** Extracts the node object from the supplied peer. */
+    protected static final Function<PeerNode, NodeObject> GET_NODE_OBJECT =
+        new Function<PeerNode, NodeObject>() {
+        public NodeObject apply (PeerNode peer) {
+            return peer.nodeobj;
+        }
+    };
+
     // (this need not use a runqueue as all it will do is post an invoker unit)
     protected Interval _peerRefresher = new Interval() {
         @Override public void expired () {