polish the code for pull request 2658

dubbo-common/src/main/java/org/apache/dubbo/common/Constants.java

@@ -247,9 +247,17 @@ public class Constants {
 
     public static final String HEARTBEAT_KEY = "heartbeat";
 
-    public static final int HEARTBEAT_TICK = 3;
+    /**
+     * Every heartbeat duration / HEATBEAT_CHECK_TICK, check if a heartbeat should be sent. Every heartbeat timeout
+     * duration / HEATBEAT_CHECK_TICK, check if a connection should be closed on server side, and if reconnect on
+     * client side
+     */
+    public static final int HEARTBEAT_CHECK_TICK = 3;
 
-    public static final long LEAST_HEARTBEAT_TICK = 1000;
+    /**
+     * the least heartbeat during is 1000 ms.
+     */
+    public static final long LEAST_HEARTBEAT_DURATION = 1000;
 
     /**
      * ticks per wheel. Currently only contains two tasks, so 16 locations are enough

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/AbstractTimerTask.java

@@ -30,43 +30,40 @@
  */
 public abstract class AbstractTimerTask implements TimerTask {
 
-    protected final ChannelProvider channelProvider;
+    private final ChannelProvider channelProvider;
 
-    protected final Long tick;
+    private final Long tick;
 
-    protected AbstractTimerTask(ChannelProvider channelProvider, Long tick) {
+    AbstractTimerTask(ChannelProvider channelProvider, Long tick) {
         if (channelProvider == null || tick == null) {
             throw new IllegalArgumentException();
         }
         this.tick = tick;
         this.channelProvider = channelProvider;
     }
 
-    protected Long lastRead(Channel channel) {
-        return (Long) channel.getAttribute(
-                HeaderExchangeHandler.KEY_READ_TIMESTAMP);
+    static Long lastRead(Channel channel) {
+        return (Long) channel.getAttribute(HeaderExchangeHandler.KEY_READ_TIMESTAMP);
     }
 
-    protected Long lastWrite(Channel channel) {
-        return (Long) channel.getAttribute(
-                HeaderExchangeHandler.KEY_WRITE_TIMESTAMP);
+    static Long lastWrite(Channel channel) {
+        return (Long) channel.getAttribute(HeaderExchangeHandler.KEY_WRITE_TIMESTAMP);
     }
 
-    protected Long now() {
+    static Long now() {
         return System.currentTimeMillis();
     }
 
-    protected void reput(Timeout timeout, Long tick) {
+    private void reput(Timeout timeout, Long tick) {
         if (timeout == null || tick == null) {
             throw new IllegalArgumentException();
         }
+
         Timer timer = timeout.timer();
-        if (timer.isStop()) {
-            return;
-        }
-        if (timeout.isCancelled()) {
+        if (timer.isStop() || timeout.isCancelled()) {
             return;
         }
+
         timer.newTimeout(timeout.task(), tick, TimeUnit.MILLISECONDS);
     }
 

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/HeaderExchangeClient.java

@@ -51,17 +51,17 @@ public HeaderExchangeClient(Client client, boolean needHeartbeat) {
         this.client = client;
         this.channel = new HeaderExchangeChannel(client);
         String dubbo = client.getUrl().getParameter(Constants.DUBBO_VERSION_KEY);
-        this.heartbeat = client.getUrl().getParameter(Constants.HEARTBEAT_KEY, dubbo != null && dubbo.startsWith("1.0.") ? Constants.DEFAULT_HEARTBEAT : 0);
+
+        this.heartbeat = client.getUrl().getParameter(Constants.HEARTBEAT_KEY, dubbo != null &&
+                dubbo.startsWith("1.0.") ? Constants.DEFAULT_HEARTBEAT : 0);
         this.heartbeatTimeout = client.getUrl().getParameter(Constants.HEARTBEAT_TIMEOUT_KEY, heartbeat * 3);
         if (heartbeatTimeout < heartbeat * 2) {
             throw new IllegalStateException("heartbeatTimeout < heartbeatInterval * 2");
         }
 
         if (needHeartbeat) {
-            long heartbeatTick = calcLeastTick(heartbeat);
-
-            // use heartbeatTick as every tick.
-            heartbeatTimer = new HashedWheelTimer(heartbeatTick, TimeUnit.MILLISECONDS, Constants.TICKS_PER_WHEEL);
+            long tickDuration = calculateLeastDuration(heartbeat);
+            heartbeatTimer = new HashedWheelTimer(tickDuration, TimeUnit.MILLISECONDS, Constants.TICKS_PER_WHEEL);
             startHeartbeatTimer();
         }
     }
@@ -179,8 +179,8 @@ public boolean hasAttribute(String key) {
     private void startHeartbeatTimer() {
         AbstractTimerTask.ChannelProvider cp = () -> Collections.singletonList(HeaderExchangeClient.this);
 
-        long heartbeatTick = calcLeastTick(heartbeat);
-        long heartbeatTimeoutTick = calcLeastTick(heartbeatTimeout);
+        long heartbeatTick = calculateLeastDuration(heartbeat);
+        long heartbeatTimeoutTick = calculateLeastDuration(heartbeatTimeout);
         HeartbeatTimerTask heartBeatTimerTask = new HeartbeatTimerTask(cp, heartbeatTick, heartbeat);
         ReconnectTimerTask reconnectTimerTask = new ReconnectTimerTask(cp, heartbeatTimeoutTick, heartbeatTimeout);
 
@@ -203,11 +203,11 @@ private void doClose() {
     /**
      * Each interval cannot be less than 1000ms.
      */
-    private long calcLeastTick(int time) {
-        if (time / Constants.HEARTBEAT_TICK <= 0) {
-            return Constants.LEAST_HEARTBEAT_TICK;
+    private long calculateLeastDuration(int time) {
+        if (time / Constants.HEARTBEAT_CHECK_TICK <= 0) {
+            return Constants.LEAST_HEARTBEAT_DURATION;
         } else {
-            return time / Constants.HEARTBEAT_TICK;
+            return time / Constants.HEARTBEAT_CHECK_TICK;
         }
     }
 

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/HeaderExchangeServer.java

@@ -33,10 +33,11 @@
 import java.net.InetSocketAddress;
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
+import static java.util.Collections.unmodifiableCollection;
+
 /**
  * ExchangeServerImpl
  */
@@ -63,9 +64,6 @@ public HeaderExchangeServer(Server server) {
             throw new IllegalStateException("heartbeatTimeout < heartbeatInterval * 2");
         }
 
-        long heartbeatTick = calcLeastTick(heartbeat);
-        // use heartbeatTick as every tick.
-        heartbeatTimer = new HashedWheelTimer(heartbeatTick, TimeUnit.MILLISECONDS, Constants.TICKS_PER_WHEEL);
         startHeartbeatTimer();
     }
 
@@ -217,10 +215,6 @@ public void reset(URL url) {
                     heartbeatTimeout = t;
 
                     stopHeartbeatTimer();
-
-                    long heartbeatTick = calcLeastTick(heartbeat);
-                    // use heartbeatTick as every tick.
-                    heartbeatTimer = new HashedWheelTimer(heartbeatTick, TimeUnit.MILLISECONDS, Constants.TICKS_PER_WHEEL);
                     startHeartbeatTimer();
                 }
             }
@@ -238,24 +232,40 @@ public void reset(org.apache.dubbo.common.Parameters parameters) {
     @Override
     public void send(Object message) throws RemotingException {
         if (closed.get()) {
-            throw new RemotingException(this.getLocalAddress(), null, "Failed to send message " + message + ", cause: The server " + getLocalAddress() + " is closed!");
+            throw new RemotingException(this.getLocalAddress(), null, "Failed to send message " + message
+                    + ", cause: The server " + getLocalAddress() + " is closed!");
         }
         server.send(message);
     }
 
     @Override
     public void send(Object message, boolean sent) throws RemotingException {
         if (closed.get()) {
-            throw new RemotingException(this.getLocalAddress(), null, "Failed to send message " + message + ", cause: The server " + getLocalAddress() + " is closed!");
+            throw new RemotingException(this.getLocalAddress(), null, "Failed to send message " + message
+                    + ", cause: The server " + getLocalAddress() + " is closed!");
         }
         server.send(message, sent);
     }
 
+    /**
+     * Each interval cannot be less than 1000ms.
+     */
+    private long calculateLeastDuration(int time) {
+        if (time / Constants.HEARTBEAT_CHECK_TICK <= 0) {
+            return Constants.LEAST_HEARTBEAT_DURATION;
+        } else {
+            return time / Constants.HEARTBEAT_CHECK_TICK;
+        }
+    }
+
     private void startHeartbeatTimer() {
-        AbstractTimerTask.ChannelProvider cp = () -> Collections.unmodifiableCollection(HeaderExchangeServer.this.getChannels());
+        long tickDuration = calculateLeastDuration(heartbeat);
+        heartbeatTimer = new HashedWheelTimer(tickDuration, TimeUnit.MILLISECONDS, Constants.TICKS_PER_WHEEL);
 
-        long heartbeatTick = calcLeastTick(heartbeat);
-        long heartbeatTimeoutTick = calcLeastTick(heartbeatTimeout);
+        AbstractTimerTask.ChannelProvider cp = () -> unmodifiableCollection(HeaderExchangeServer.this.getChannels());
+
+        long heartbeatTick = calculateLeastDuration(heartbeat);
+        long heartbeatTimeoutTick = calculateLeastDuration(heartbeatTimeout);
         HeartbeatTimerTask heartBeatTimerTask = new HeartbeatTimerTask(cp, heartbeatTick, heartbeat);
         ReconnectTimerTask reconnectTimerTask = new ReconnectTimerTask(cp, heartbeatTimeoutTick, heartbeatTimeout);
 
@@ -264,17 +274,6 @@ private void startHeartbeatTimer() {
         heartbeatTimer.newTimeout(reconnectTimerTask, heartbeatTimeoutTick, TimeUnit.MILLISECONDS);
     }
 
-    /**
-     * Each interval cannot be less than 1000ms.
-     */
-    private long calcLeastTick(int time) {
-        if (time / Constants.HEARTBEAT_TICK <= 0) {
-            return Constants.LEAST_HEARTBEAT_TICK;
-        } else {
-            return time / Constants.HEARTBEAT_TICK;
-        }
-    }
-
     private void stopHeartbeatTimer() {
         if (heartbeatTimer != null) {
             heartbeatTimer.stop();

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/HeartbeatTimerTask.java

@@ -32,7 +32,7 @@ public class HeartbeatTimerTask extends AbstractTimerTask {
 
     private final int heartbeat;
 
-    protected HeartbeatTimerTask(ChannelProvider channelProvider, Long heartbeatTick, int heartbeat) {
+    HeartbeatTimerTask(ChannelProvider channelProvider, Long heartbeatTick, int heartbeat) {
         super(channelProvider, heartbeatTick);
         this.heartbeat = heartbeat;
     }
@@ -51,7 +51,8 @@ protected void doTask(Channel channel) {
                 channel.send(req);
                 if (logger.isDebugEnabled()) {
                     logger.debug("Send heartbeat to remote channel " + channel.getRemoteAddress()
-                            + ", cause: The channel has no data-transmission exceeds a heartbeat period: " + heartbeat + "ms");
+                            + ", cause: The channel has no data-transmission exceeds a heartbeat period: "
+                            + heartbeat + "ms");
                 }
             }
         } catch (Throwable t) {

dubbo-remoting/dubbo-remoting-api/src/main/java/org/apache/dubbo/remoting/exchange/support/header/ReconnectTimerTask.java

@@ -31,7 +31,7 @@ public class ReconnectTimerTask extends AbstractTimerTask {
 
     private final int heartbeatTimeout;
 
-    protected ReconnectTimerTask(ChannelProvider channelProvider, Long heartbeatTimeoutTick, int heartbeatTimeout1) {
+    ReconnectTimerTask(ChannelProvider channelProvider, Long heartbeatTimeoutTick, int heartbeatTimeout1) {
         super(channelProvider, heartbeatTimeoutTick);
         this.heartbeatTimeout = heartbeatTimeout1;
     }
@@ -42,8 +42,8 @@ protected void doTask(Channel channel) {
             Long lastRead = lastRead(channel);
             Long now = now();
             if (lastRead != null && now - lastRead > heartbeatTimeout) {
-                logger.warn("Close channel " + channel
-                        + ", because heartbeat read idle time out: " + heartbeatTimeout + "ms");
+                logger.warn("Close channel " + channel + ", because heartbeat read idle time out: "
+                        + heartbeatTimeout + "ms");
                 if (channel instanceof Client) {
                     try {
                         ((Client) channel).reconnect();

dubbo-remoting/dubbo-remoting-api/src/test/java/org/apache/dubbo/remoting/exchange/support/header/HeartBeatTaskTest.java

@@ -42,7 +42,7 @@ public class HeartBeatTaskTest {
     @Before
     public void setup() throws Exception {
         long tickDuration = 1000;
-        heartbeatTimer = new HashedWheelTimer(tickDuration / Constants.HEARTBEAT_TICK, TimeUnit.MILLISECONDS);
+        heartbeatTimer = new HashedWheelTimer(tickDuration / Constants.HEARTBEAT_CHECK_TICK, TimeUnit.MILLISECONDS);
 
         channel = new MockChannel() {
 
@@ -53,7 +53,7 @@ public URL getUrl() {
         };
 
         AbstractTimerTask.ChannelProvider cp = () -> Collections.<Channel>singletonList(channel);
-        heartbeatTimerTask = new HeartbeatTimerTask(cp, tickDuration / Constants.HEARTBEAT_TICK, (int) tickDuration);
+        heartbeatTimerTask = new HeartbeatTimerTask(cp, tickDuration / Constants.HEARTBEAT_CHECK_TICK, (int) tickDuration);
     }
 
     @Test