[Improvement][remote] Refactor remote module to fix code smell (#4576)

* chore[remote]: Refactor remote module to fix code smell

* chore[remote]: Add licence header

* chore[remote]: Clean code smell

* chore[remote]: Clean code smell

* chore[remote]: Remove unused import

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/NettyRemotingClient.java

@@ -55,7 +55,6 @@ import org.slf4j.LoggerFactory;
 import io.netty.bootstrap.Bootstrap;
 import io.netty.channel.Channel;
 import io.netty.channel.ChannelFuture;
-import io.netty.channel.ChannelFutureListener;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
@@ -84,7 +83,7 @@ public class NettyRemotingClient {
     /**
      * channels
      */
-    private final ConcurrentHashMap<Host, Channel> channels = new ConcurrentHashMap(128);
+    private final ConcurrentHashMap<Host, Channel> channels = new ConcurrentHashMap<>(128);
 
     /**
      * started flag
@@ -130,7 +129,7 @@ public class NettyRemotingClient {
         this.clientConfig = clientConfig;
         if (NettyUtils.useEpoll()) {
             this.workerGroup = new EpollEventLoopGroup(clientConfig.getWorkerThreads(), new ThreadFactory() {
-                private AtomicInteger threadIndex = new AtomicInteger(0);
+                private final AtomicInteger threadIndex = new AtomicInteger(0);
 
                 @Override
                 public Thread newThread(Runnable r) {
@@ -139,7 +138,7 @@ public class NettyRemotingClient {
             });
         } else {
             this.workerGroup = new NioEventLoopGroup(clientConfig.getWorkerThreads(), new ThreadFactory() {
-                private AtomicInteger threadIndex = new AtomicInteger(0);
+                private final AtomicInteger threadIndex = new AtomicInteger(0);
 
                 @Override
                 public Thread newThread(Runnable r) {
@@ -178,13 +177,7 @@ public class NettyRemotingClient {
                                 .addLast(new NettyDecoder(), clientHandler, encoder);
                     }
                 });
-        this.responseFutureExecutor.scheduleAtFixedRate(new Runnable() {
+        this.responseFutureExecutor.scheduleAtFixedRate(ResponseFuture::scanFutureTable, 5000, 1000, TimeUnit.MILLISECONDS);
-            @Override
-            public void run() {
-                ResponseFuture.scanFutureTable();
-            }
-        }, 5000, 1000, TimeUnit.MILLISECONDS);
-        //
         isStarted.compareAndSet(false, true);
     }
 
@@ -195,8 +188,6 @@ public class NettyRemotingClient {
      * @param command command
      * @param timeoutMillis timeoutMillis
      * @param invokeCallback callback function
-     * @throws InterruptedException
-     * @throws RemotingException
      */
     public void sendAsync(final Host host, final Command command,
                           final long timeoutMillis,
@@ -205,18 +196,18 @@ public class NettyRemotingClient {
         if (channel == null) {
             throw new RemotingException("network error");
         }
-        /**
+        /*
          * request unique identification
          */
         final long opaque = command.getOpaque();
-        /**
+        /*
          *  control concurrency number
          */
         boolean acquired = this.asyncSemaphore.tryAcquire(timeoutMillis, TimeUnit.MILLISECONDS);
         if (acquired) {
             final ReleaseSemaphore releaseSemaphore = new ReleaseSemaphore(this.asyncSemaphore);
 
-            /**
+            /*
              *  response future
              */
             final ResponseFuture responseFuture = new ResponseFuture(opaque,
@@ -224,10 +215,7 @@ public class NettyRemotingClient {
                     invokeCallback,
                     releaseSemaphore);
             try {
-                channel.writeAndFlush(command).addListener(new ChannelFutureListener() {
+                channel.writeAndFlush(command).addListener(future -> {
-
-                    @Override
-                    public void operationComplete(ChannelFuture future) throws Exception {
                     if (future.isSuccess()) {
                         responseFuture.setSendOk(true);
                         return;
@@ -238,14 +226,13 @@ public class NettyRemotingClient {
                     responseFuture.putResponse(null);
                     try {
                         responseFuture.executeInvokeCallback();
-                        } catch (Throwable ex) {
+                    } catch (Exception ex) {
                         logger.error("execute callback error", ex);
                     } finally {
                         responseFuture.release();
                     }
-                    }
                 });
-            } catch (Throwable ex) {
+            } catch (Exception ex) {
                 responseFuture.release();
                 throw new RemotingException(String.format("send command to host: %s failed", host), ex);
             }
@@ -263,8 +250,6 @@ public class NettyRemotingClient {
      * @param command command
      * @param timeoutMillis timeoutMillis
      * @return command
-     * @throws InterruptedException
-     * @throws RemotingException
      */
     public Command sendSync(final Host host, final Command command, final long timeoutMillis) throws InterruptedException, RemotingException {
         final Channel channel = getChannel(host);
@@ -273,9 +258,7 @@ public class NettyRemotingClient {
         }
         final long opaque = command.getOpaque();
         final ResponseFuture responseFuture = new ResponseFuture(opaque, timeoutMillis, null, null);
-        channel.writeAndFlush(command).addListener(new ChannelFutureListener() {
+        channel.writeAndFlush(command).addListener(future -> {
-            @Override
-            public void operationComplete(ChannelFuture future) throws Exception {
             if (future.isSuccess()) {
                 responseFuture.setSendOk(true);
                 return;
@@ -285,9 +268,8 @@ public class NettyRemotingClient {
             responseFuture.setCause(future.cause());
             responseFuture.putResponse(null);
             logger.error("send command {} to host {} failed", command, host);
-            }
         });
-        /**
+        /*
          * sync wait for result
          */
         Command result = responseFuture.waitResponse();
@@ -306,7 +288,6 @@ public class NettyRemotingClient {
      *
      * @param host host
      * @param command command
-     * @throws RemotingException
      */
     public void send(final Host host, final Command command) throws RemotingException {
         Channel channel = getChannel(host);
@@ -351,9 +332,6 @@ public class NettyRemotingClient {
 
     /**
      * get channel
-     *
-     * @param host
-     * @return
      */
     public Channel getChannel(Host host) {
         Channel channel = channels.get(host);

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/NettyRemotingServer.java

@@ -21,6 +21,7 @@ import org.apache.dolphinscheduler.remote.codec.NettyDecoder;
 import org.apache.dolphinscheduler.remote.codec.NettyEncoder;
 import org.apache.dolphinscheduler.remote.command.CommandType;
 import org.apache.dolphinscheduler.remote.config.NettyServerConfig;
+import org.apache.dolphinscheduler.remote.exceptions.RemoteException;
 import org.apache.dolphinscheduler.remote.handler.NettyServerHandler;
 import org.apache.dolphinscheduler.remote.processor.NettyRequestProcessor;
 import org.apache.dolphinscheduler.remote.utils.Constants;
@@ -93,6 +94,11 @@ public class NettyRemotingServer {
      */
     private final AtomicBoolean isStarted = new AtomicBoolean(false);
 
+    /**
+     * Netty server bind fail message
+     */
+    private static final String NETTY_BIND_FAILURE_MSG = "NettyRemotingServer bind %s fail";
+
     /**
      * server init
      *
@@ -102,7 +108,7 @@ public class NettyRemotingServer {
         this.serverConfig = serverConfig;
         if (NettyUtils.useEpoll()) {
             this.bossGroup = new EpollEventLoopGroup(1, new ThreadFactory() {
-                private AtomicInteger threadIndex = new AtomicInteger(0);
+                private final AtomicInteger threadIndex = new AtomicInteger(0);
 
                 @Override
                 public Thread newThread(Runnable r) {
@@ -111,7 +117,7 @@ public class NettyRemotingServer {
             });
 
             this.workGroup = new EpollEventLoopGroup(serverConfig.getWorkerThread(), new ThreadFactory() {
-                private AtomicInteger threadIndex = new AtomicInteger(0);
+                private final AtomicInteger threadIndex = new AtomicInteger(0);
 
                 @Override
                 public Thread newThread(Runnable r) {
@@ -120,7 +126,7 @@ public class NettyRemotingServer {
             });
         } else {
             this.bossGroup = new NioEventLoopGroup(1, new ThreadFactory() {
-                private AtomicInteger threadIndex = new AtomicInteger(0);
+                private final AtomicInteger threadIndex = new AtomicInteger(0);
 
                 @Override
                 public Thread newThread(Runnable r) {
@@ -129,7 +135,7 @@ public class NettyRemotingServer {
             });
 
             this.workGroup = new NioEventLoopGroup(serverConfig.getWorkerThread(), new ThreadFactory() {
-                private AtomicInteger threadIndex = new AtomicInteger(0);
+                private final AtomicInteger threadIndex = new AtomicInteger(0);
 
                 @Override
                 public Thread newThread(Runnable r) {
@@ -156,7 +162,7 @@ public class NettyRemotingServer {
                     .childHandler(new ChannelInitializer<SocketChannel>() {
 
                         @Override
-                    protected void initChannel(SocketChannel ch) throws Exception {
+                        protected void initChannel(SocketChannel ch) {
                             initNettyChannel(ch);
                         }
                     });
@@ -166,14 +172,14 @@ public class NettyRemotingServer {
                 future = serverBootstrap.bind(serverConfig.getListenPort()).sync();
             } catch (Exception e) {
                 logger.error("NettyRemotingServer bind fail {}, exit", e.getMessage(), e);
-                throw new RuntimeException(String.format("NettyRemotingServer bind %s fail", serverConfig.getListenPort()));
+                throw new RemoteException(String.format(NETTY_BIND_FAILURE_MSG, serverConfig.getListenPort()));
             }
             if (future.isSuccess()) {
                 logger.info("NettyRemotingServer bind success at port : {}", serverConfig.getListenPort());
             } else if (future.cause() != null) {
-                throw new RuntimeException(String.format("NettyRemotingServer bind %s fail", serverConfig.getListenPort()), future.cause());
+                throw new RemoteException(String.format(NETTY_BIND_FAILURE_MSG, serverConfig.getListenPort()), future.cause());
             } else {
-                throw new RuntimeException(String.format("NettyRemotingServer bind %s fail", serverConfig.getListenPort()));
+                throw new RemoteException(String.format(NETTY_BIND_FAILURE_MSG, serverConfig.getListenPort()));
             }
         }
     }

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/codec/NettyEncoder.java

@@ -14,13 +14,16 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
 package org.apache.dolphinscheduler.remote.codec;
 
+import org.apache.dolphinscheduler.remote.command.Command;
+import org.apache.dolphinscheduler.remote.exceptions.RemotingException;
+
 import io.netty.buffer.ByteBuf;
 import io.netty.channel.ChannelHandler.Sharable;
 import io.netty.channel.ChannelHandlerContext;
 import io.netty.handler.codec.MessageToByteEncoder;
-import org.apache.dolphinscheduler.remote.command.Command;
 
 /**
  * netty encoder
@@ -34,12 +37,11 @@ public class NettyEncoder extends MessageToByteEncoder<Command> {
      * @param ctx channel handler context
      * @param msg command
      * @param out byte buffer
-     * @throws Exception
      */
     @Override
     protected void encode(ChannelHandlerContext ctx, Command msg, ByteBuf out) throws Exception {
-        if(msg == null){
+        if (msg == null) {
-            throw new Exception("encode msg is null");
+            throw new RemotingException("encode msg is null");
         }
         out.writeByte(Command.MAGIC);
         out.writeByte(Command.VERSION);

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/command/TaskKillResponseCommand.java

@@ -51,7 +51,7 @@ public class TaskKillResponseCommand implements Serializable {
     /**
      * other resource manager appId , for example : YARN etc
      */
-    protected List<String> appIds;
+    private List<String> appIds;
 
     public int getTaskInstanceId() {
         return taskInstanceId;

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/exceptions/RemoteException.java

@@ -0,0 +1,42 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.dolphinscheduler.remote.exceptions;
+
+/**
+ * Custom runtime exception
+ */
+public class RemoteException extends RuntimeException {
+
+    /**
+     * Construct a new runtime exception with the detail message
+     *
+     * @param   message  detail message
+     */
+    public RemoteException(String message) {
+        super(message);
+    }
+
+    /**
+     * Construct a new runtime exception with the detail message and cause
+     *
+     * @param   message  detail message
+     */
+    public RemoteException(String message, Throwable cause) {
+        super(message, cause);
+    }
+}

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/future/ResponseFuture.java

@@ -18,14 +18,17 @@
 package org.apache.dolphinscheduler.remote.future;
 
 import org.apache.dolphinscheduler.remote.command.Command;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.*;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * response future
@@ -34,7 +37,7 @@ public class ResponseFuture {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(ResponseFuture.class);
 
-    private static final ConcurrentHashMap<Long,ResponseFuture> FUTURE_TABLE = new ConcurrentHashMap<>(256);
+    private static final ConcurrentHashMap<Long, ResponseFuture> FUTURE_TABLE = new ConcurrentHashMap<>(256);
 
     /**
      * request unique identification
@@ -81,7 +84,6 @@ public class ResponseFuture {
      * wait for response
      *
      * @return command
-     * @throws InterruptedException
      */
     public Command waitResponse() throws InterruptedException {
         this.latch.await(timeoutMillis, TimeUnit.MILLISECONDS);
@@ -99,12 +101,13 @@ public class ResponseFuture {
         FUTURE_TABLE.remove(opaque);
     }
 
-    public static ResponseFuture getFuture(long opaque){
+    public static ResponseFuture getFuture(long opaque) {
         return FUTURE_TABLE.get(opaque);
     }
 
     /**
      * whether timeout
+     *
      * @return timeout
      */
     public boolean isTimeout() {
@@ -165,7 +168,7 @@ public class ResponseFuture {
      * release
      */
     public void release() {
-        if(this.releaseSemaphore != null){
+        if (this.releaseSemaphore != null) {
             this.releaseSemaphore.release();
         }
     }
@@ -173,7 +176,7 @@ public class ResponseFuture {
     /**
      * scan future table
      */
-    public static void scanFutureTable(){
+    public static void scanFutureTable() {
         final List<ResponseFuture> futureList = new LinkedList<>();
         Iterator<Map.Entry<Long, ResponseFuture>> it = FUTURE_TABLE.entrySet().iterator();
         while (it.hasNext()) {
@@ -189,7 +192,7 @@ public class ResponseFuture {
             try {
                 future.release();
                 future.executeInvokeCallback();
-            } catch (Throwable ex) {
+            } catch (Exception ex) {
                 LOGGER.warn("scanFutureTable, execute callback error", ex);
             }
         }
@@ -197,16 +200,16 @@ public class ResponseFuture {
 
     @Override
     public String toString() {
-        return "ResponseFuture{" +
+        return "ResponseFuture{"
-                "opaque=" + opaque +
+                + "opaque=" + opaque
-                ", timeoutMillis=" + timeoutMillis +
+                + ", timeoutMillis=" + timeoutMillis
-                ", invokeCallback=" + invokeCallback +
+                + ", invokeCallback=" + invokeCallback
-                ", releaseSemaphore=" + releaseSemaphore +
+                + ", releaseSemaphore=" + releaseSemaphore
-                ", latch=" + latch +
+                + ", latch=" + latch
-                ", beginTimestamp=" + beginTimestamp +
+                + ", beginTimestamp=" + beginTimestamp
-                ", responseCommand=" + responseCommand +
+                + ", responseCommand=" + responseCommand
-                ", sendOk=" + sendOk +
+                + ", sendOk=" + sendOk
-                ", cause=" + cause +
+                + ", cause=" + cause
-                '}';
+                + '}';
     }
 }

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/handler/NettyClientHandler.java

@@ -74,7 +74,7 @@ public class NettyClientHandler extends ChannelInboundHandlerAdapter {
     public NettyClientHandler(NettyRemotingClient nettyRemotingClient, ExecutorService callbackExecutor) {
         this.nettyRemotingClient = nettyRemotingClient;
         this.callbackExecutor = callbackExecutor;
-        this.processors = new ConcurrentHashMap();
+        this.processors = new ConcurrentHashMap<>();
     }
 
     /**
@@ -82,10 +82,9 @@ public class NettyClientHandler extends ChannelInboundHandlerAdapter {
      * the current channel has reached the end of its life cycle
      *
      * @param ctx channel handler context
-     * @throws Exception
      */
     @Override
-    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
+    public void channelInactive(ChannelHandlerContext ctx) {
         nettyRemotingClient.closeChannel(ChannelUtils.toAddress(ctx.channel()));
         ctx.channel().close();
     }
@@ -95,10 +94,9 @@ public class NettyClientHandler extends ChannelInboundHandlerAdapter {
      *
      * @param ctx channel handler context
      * @param msg message
-     * @throws Exception
      */
     @Override
-    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+    public void channelRead(ChannelHandlerContext ctx, Object msg) {
         processReceived(ctx.channel(), (Command) msg);
     }
 
@@ -138,12 +136,7 @@ public class NettyClientHandler extends ChannelInboundHandlerAdapter {
             future.setResponseCommand(command);
             future.release();
             if (future.getInvokeCallback() != null) {
-                this.callbackExecutor.submit(new Runnable() {
+                this.callbackExecutor.submit(future::executeInvokeCallback);
-                    @Override
-                    public void run() {
-                        future.executeInvokeCallback();
-                    }
-                });
             } else {
                 future.putResponse(command);
             }
@@ -158,7 +151,7 @@ public class NettyClientHandler extends ChannelInboundHandlerAdapter {
             Runnable run = () -> {
                 try {
                     pair.getLeft().process(channel, command);
-                } catch (Throwable e) {
+                } catch (Exception e) {
                     logger.error(String.format("process command %s exception", command), e);
                 }
             };
@@ -177,11 +170,10 @@ public class NettyClientHandler extends ChannelInboundHandlerAdapter {
      *
      * @param ctx channel handler context
      * @param cause cause
-     * @throws Exception
      */
     @Override
-    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
+    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
-        logger.error("exceptionCaught : {}", cause);
+        logger.error("exceptionCaught : {}", cause.getMessage(), cause);
         nettyRemotingClient.closeChannel(ChannelUtils.toAddress(ctx.channel()));
         ctx.channel().close();
     }

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/handler/NettyServerHandler.java

@@ -55,7 +55,7 @@ public class NettyServerHandler extends ChannelInboundHandlerAdapter {
     /**
      * server processors queue
      */
-    private final ConcurrentHashMap<CommandType, Pair<NettyRequestProcessor, ExecutorService>> processors = new ConcurrentHashMap();
+    private final ConcurrentHashMap<CommandType, Pair<NettyRequestProcessor, ExecutorService>> processors = new ConcurrentHashMap<>();
 
     public NettyServerHandler(NettyRemotingServer nettyRemotingServer) {
         this.nettyRemotingServer = nettyRemotingServer;
@@ -66,10 +66,9 @@ public class NettyServerHandler extends ChannelInboundHandlerAdapter {
      * the current channel has reached the end of its life cycle
      *
      * @param ctx channel handler context
-     * @throws Exception
      */
     @Override
-    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
+    public void channelInactive(ChannelHandlerContext ctx) {
         ctx.channel().close();
     }
 
@@ -78,10 +77,9 @@ public class NettyServerHandler extends ChannelInboundHandlerAdapter {
      *
      * @param ctx channel handler context
      * @param msg message
-     * @throws Exception
      */
     @Override
-    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
+    public void channelRead(ChannelHandlerContext ctx, Object msg) {
         processReceived(ctx.channel(), (Command) msg);
     }
 
@@ -120,16 +118,12 @@ public class NettyServerHandler extends ChannelInboundHandlerAdapter {
         final CommandType commandType = msg.getType();
         final Pair<NettyRequestProcessor, ExecutorService> pair = processors.get(commandType);
         if (pair != null) {
-            Runnable r = new Runnable() {
+            Runnable r = () -> {
-
-                @Override
-                public void run() {
                 try {
                     pair.getLeft().process(channel, msg);
-                    } catch (Throwable ex) {
+                } catch (Exception ex) {
                     logger.error("process msg {} error", msg, ex);
                 }
-                }
             };
             try {
                 pair.getRight().submit(r);
@@ -146,7 +140,6 @@ public class NettyServerHandler extends ChannelInboundHandlerAdapter {
      *
      * @param ctx channel handler context
      * @param cause cause
-     * @throws Exception
      */
     @Override
     public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
@@ -158,7 +151,6 @@ public class NettyServerHandler extends ChannelInboundHandlerAdapter {
      * channel write changed
      *
      * @param ctx channel handler context
-     * @throws Exception
      */
     @Override
     public void channelWritabilityChanged(ChannelHandlerContext ctx) throws Exception {

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/utils/ChannelUtils.java

@@ -14,43 +14,50 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.dolphinscheduler.remote.utils;
 
-import io.netty.channel.Channel;
+package org.apache.dolphinscheduler.remote.utils;
 
 import java.net.InetSocketAddress;
 
+import io.netty.channel.Channel;
+
 /**
  * channel utils
  */
 public class ChannelUtils {
 
+    private ChannelUtils() {
+        throw new IllegalStateException(ChannelUtils.class.getName());
+    }
+
     /**
      * get local address
      *
      * @param channel channel
      * @return local address
      */
-    public static String getLocalAddress(Channel channel){
+    public static String getLocalAddress(Channel channel) {
-        return ((InetSocketAddress)channel.localAddress()).getAddress().getHostAddress();
+        return ((InetSocketAddress) channel.localAddress()).getAddress().getHostAddress();
     }
 
     /**
      * get remote address
+     *
      * @param channel channel
      * @return remote address
      */
-    public static String getRemoteAddress(Channel channel){
+    public static String getRemoteAddress(Channel channel) {
-        return ((InetSocketAddress)channel.remoteAddress()).getAddress().getHostAddress();
+        return ((InetSocketAddress) channel.remoteAddress()).getAddress().getHostAddress();
     }
 
     /**
      * channel to address
+     *
      * @param channel channel
      * @return address
      */
-    public static Host toAddress(Channel channel){
+    public static Host toAddress(Channel channel) {
-        InetSocketAddress socketAddress = ((InetSocketAddress)channel.remoteAddress());
+        InetSocketAddress socketAddress = ((InetSocketAddress) channel.remoteAddress());
         return new Host(socketAddress.getAddress().getHostAddress(), socketAddress.getPort());
     }
 

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/utils/Constants.java

@@ -25,6 +25,10 @@ import java.nio.charset.StandardCharsets;
  */
 public class Constants {
 
+    private Constants() {
+        throw new IllegalStateException(Constants.class.getName());
+    }
+
     public static final String COMMA = ",";
 
     public static final String SLASH = "/";

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/utils/IPUtils.java

@@ -16,6 +16,8 @@
  */
 package org.apache.dolphinscheduler.remote.utils;
 
+import org.apache.dolphinscheduler.remote.exceptions.RemoteException;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -28,22 +30,24 @@ import java.util.regex.Pattern;
 
 public class IPUtils {
 
-    private static final Logger logger = LoggerFactory.getLogger(IPUtils.class);
+    private IPUtils() {
+        throw new IllegalStateException(IPUtils.class.getName());
+    }
 
-    private static String IP_REGEX = "([1-9]|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3}";
+    private static final Logger logger = LoggerFactory.getLogger(IPUtils.class);
 
-    private static String LOCAL_HOST = "unknown";
+    private static String localHost = "unknown";
 
     static {
         String host = System.getenv("HOSTNAME");
         if (isNotEmpty(host)) {
-            LOCAL_HOST = host;
+            localHost = host;
         } else {
 
             try {
                 String hostName = InetAddress.getLocalHost().getHostName();
                 if (isNotEmpty(hostName)) {
-                    LOCAL_HOST = hostName;
+                    localHost = hostName;
                 }
             } catch (UnknownHostException e) {
                 logger.error("get hostName error!", e);
@@ -52,7 +56,7 @@ public class IPUtils {
     }
 
     public static String getLocalHost() {
-        return LOCAL_HOST;
+        return localHost;
     }
 
 
@@ -100,7 +104,7 @@ public class IPUtils {
 
             return addresses;
         } catch (SocketException e) {
-            throw new RuntimeException(e.getMessage(), e);
+            throw new RemoteException(e.getMessage(), e);
         }
     }
 
@@ -131,12 +135,11 @@ public class IPUtils {
             return false;
         }
 
-        Pattern pat = Pattern.compile(IP_REGEX);
+        String ipRegex = "([1-9]|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])(\\.(\\d|[1-9]\\d|1\\d{2}|2[0-4]\\d|25[0-5])){3}";
+        Pattern pat = Pattern.compile(ipRegex);
 
         Matcher mat = pat.matcher(addr);
 
-        boolean ipAddress = mat.find();
+        return mat.find();
-
-        return ipAddress;
     }
 }

dolphinscheduler-remote/src/main/java/org/apache/dolphinscheduler/remote/utils/Pair.java

@@ -17,7 +17,6 @@
 
 package org.apache.dolphinscheduler.remote.utils;
 
-
 /**
  * key value pair
  *
@@ -51,7 +50,7 @@ public class Pair<L, R> {
         this.right = right;
     }
 
-    public static <L, R> Pair of(L left, R right){
+    public static <L, R> Pair<L, R> of(L left, R right) {
-        return new Pair(left, right);
+        return new Pair<>(left, right);
     }
 }