From 165912365a8a375c32f2747ca0836fd604f4ad17 Mon Sep 17 00:00:00 2001
From: Dmitriy Dumanskiy <dmitriy@blynk.cc>
Date: Wed, 16 Jan 2019 12:00:25 +0200
Subject: [PATCH] Clenaup: simplify EpollEventLoop.closeAll() (#8719)

Motivation:

Avoid unnecessary iteration and `ArrayList` allocation.

Modification:

```
for (AbstractEpollChannel channel: channels.values()) {
     array.add(channel);
}
```
replaced with

`array.addAll(channels.values())`

and

```
Collection<AbstractEpollChannel> array = new ArrayList<AbstractEpollChannel>(channels.size());
array.addAll(channels.values())
```

replaced with:

`AbstractEpollChannel[] localChannels = channels.values().toArray(new AbstractEpollChannel[0]);`

Result:

Simpler code in `EpollEventLoop.closeAll();`
---
 .../java/io/netty/channel/epoll/EpollEventLoop.java    | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollEventLoop.java b/transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollEventLoop.java
index 33adf86279..3420d67bc8 100644
--- a/transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollEventLoop.java
+++ b/transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollEventLoop.java
@@ -32,8 +32,6 @@ import io.netty.util.internal.logging.InternalLogger;
 import io.netty.util.internal.logging.InternalLoggerFactory;
 
 import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collection;
 import java.util.Queue;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicIntegerFieldUpdater;
@@ -379,13 +377,9 @@ class EpollEventLoop extends SingleThreadEventLoop {
         }
         // Using the intermediate collection to prevent ConcurrentModificationException.
         // In the `close()` method, the channel is deleted from `channels` map.
-        Collection<AbstractEpollChannel> array = new ArrayList<AbstractEpollChannel>(channels.size());
+        AbstractEpollChannel[] localChannels = channels.values().toArray(new AbstractEpollChannel[0]);
 
-        for (AbstractEpollChannel channel: channels.values()) {
-            array.add(channel);
-        }
-
-        for (AbstractEpollChannel ch: array) {
+        for (AbstractEpollChannel ch : localChannels) {
             ch.unsafe().close(ch.unsafe().voidPromise());
         }
     }