Code enhancement for #161

Signed-off-by: Eric Zhao <sczyh16@gmail.com>

sentinel-core/src/main/java/com/alibaba/csp/sentinel/config/SentinelConfig.java

@@ -69,7 +69,7 @@ public class SentinelConfig {
             String fileName = LogBase.getLogBaseDir() + appName + ".properties";
             File file = new File(fileName);
             if (file.exists()) {
-                RecordLog.info("read SentinelConfig from " + fileName);
+                RecordLog.info("[SentinelConfig] Reading config from " + fileName);
                 FileInputStream fis = new FileInputStream(fileName);
                 Properties fileProps = new Properties();
                 fileProps.load(fis);
@@ -90,7 +90,7 @@ public class SentinelConfig {
             String configValueOld = getConfig(configKey);
             SentinelConfig.setConfig(configKey, configValue);
             if (configValueOld != null) {
-                RecordLog.info("JVM parameter overrides {0}: {1} -> {2}", configKey, configValueOld, configValue);
+                RecordLog.info("[SentinelConfig] JVM parameter overrides {0}: {1} -> {2}", configKey, configValueOld, configValue);
             }
         }
     }
@@ -128,7 +128,7 @@ public class SentinelConfig {
         try {
             return Long.parseLong(props.get(SINGLE_METRIC_FILE_SIZE));
         } catch (Throwable throwable) {
-            RecordLog.info("SentinelConfig get singleMetricFileSize fail, use default value: "
+            RecordLog.info("[SentinelConfig] Parse singleMetricFileSize fail, use default value: "
                 + DEFAULT_SINGLE_METRIC_FILE_SIZE, throwable);
             return DEFAULT_SINGLE_METRIC_FILE_SIZE;
         }
@@ -138,7 +138,7 @@ public class SentinelConfig {
         try {
             return Integer.parseInt(props.get(TOTAL_METRIC_FILE_COUNT));
         } catch (Throwable throwable) {
-            RecordLog.info("SentinelConfig get totalMetricFileCount fail, use default value: "
+            RecordLog.info("[SentinelConfig] Parse totalMetricFileCount fail, use default value: "
                 + DEFAULT_TOTAL_METRIC_FILE_COUNT, throwable);
             return DEFAULT_TOTAL_METRIC_FILE_COUNT;
         }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/log/CommandCenterLog.java

@@ -32,7 +32,6 @@ public class CommandCenterLog extends LogBase {
         logHandler = makeLogger(FILE_NAME, heliumRecordLog);
     }
 
-
     public static void info(String detail, Object... params) {
         log(heliumRecordLog, logHandler, Level.INFO, detail, params);
     }

sentinel-core/src/main/java/com/alibaba/csp/sentinel/util/VersionUtil.java

@@ -18,19 +18,22 @@ package com.alibaba.csp.sentinel.util;
 import com.alibaba.csp.sentinel.log.RecordLog;
 
 /**
- * Get Sentinel version from MANIFEST.MF
+ * Get version of Sentinel from {@code MANIFEST.MF} file.
  * 
  * @author jason
  * @since 0.2.1
  */
-public class VersionUtil {
+public final class VersionUtil {
+
     public static String getVersion(String defaultVersion) {
         try {
             String version = VersionUtil.class.getPackage().getImplementationVersion();
-            return version == null || version.length() == 0 ? defaultVersion : version;
+            return StringUtil.isBlank(version) ? defaultVersion : version;
         } catch (Throwable e) {
-            RecordLog.warn("return default version, ignore exception", e);
+            RecordLog.warn("Using default version, ignore exception", e);
             return defaultVersion;
         }
     }
+
+    private VersionUtil() {}
 }

sentinel-core/src/test/java/com/alibaba/csp/sentinel/util/VersionUtilTest.java

@@ -1,15 +1,30 @@
+/*
+ * Copyright 1999-2018 Alibaba Group Holding Ltd.
+ *
+ * Licensed 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 com.alibaba.csp.sentinel.util;
 
 import org.junit.Assert;
 import org.junit.Test;
 
 public class VersionUtilTest {
+
     @Test
-    public void versionTest() {
-        String version = VersionUtil.getVersion("1.0");
-        /**
-         * manifest cannot be load before package
-         */
-        Assert.assertEquals("1.0", version);
+    public void testGetDefaultVersion() {
+        String defaultVersion = "1.0";
+        String version = VersionUtil.getVersion(defaultVersion);
+        // Manifest cannot be load before package.
+        Assert.assertEquals(defaultVersion, version);
     }
 }

sentinel-transport/sentinel-transport-netty-http/src/main/java/com/alibaba/csp/sentinel/transport/command/netty/HttpServer.java

@@ -62,6 +62,7 @@ public final class HttpServer {
                     port = Integer.parseInt(TransportConfig.getPort());
                 }
             } catch (Exception e) {
+                // Will cause the application exit.
                 throw new IllegalArgumentException("Illegal port: " + TransportConfig.getPort());
             }
             
@@ -73,10 +74,11 @@ public final class HttpServer {
                 try {
                     channelFuture = b.bind(newPort).sync();
                     TransportConfig.setRuntimePort(newPort);
+                    CommandCenterLog.info("[NettyHttpCommandCenter] Begin listening at port " + newPort);
                     break;
                 } catch (Exception e) {
                     TimeUnit.MILLISECONDS.sleep(30);
-                    RecordLog.warn("netty server bind error, port={0}, retry={1}", newPort, retryCount);
+                    RecordLog.warn("[HttpServer] Netty server bind error, port={0}, retry={1}", newPort, retryCount);
                     retryCount ++;
                 }
             }
@@ -89,11 +91,11 @@ public final class HttpServer {
     }
     
     /**
-     * increase port number every 3 tries
+     * Increase port number every 3 tries.
      * 
-     * @param basePort
-     * @param retryCount
-     * @return
+     * @param basePort base port to start
+     * @param retryCount retry count
+     * @return next calculated port
      */
     private int getNewPort(int basePort, int retryCount) {
         return basePort + retryCount / 3;
@@ -109,7 +111,7 @@ public final class HttpServer {
         }
 
         if (handlerMap.containsKey(commandName)) {
-            CommandCenterLog.info("Register failed (duplicate command): " + commandName);
+            CommandCenterLog.warn("[NettyHttpCommandCenter] Register failed (duplicate command): " + commandName);
             return;
         }
 

sentinel-transport/sentinel-transport-simple-http/src/main/java/com/alibaba/csp/sentinel/transport/command/SimpleHttpCommandCenter.java

@@ -121,12 +121,11 @@ public class SimpleHttpCommandCenter implements CommandCenter {
     }
     
     /**
-     * Get a server socket from an avaliable port from a base port.<br>
-     * Increasement on port number will happen when the port has already been
-     * used.<br>
+     * Get a server socket from an available port from a base port.<br>
+     * Increasing on port number will occur when the port has already been used.
      * 
-     * @param basePort
-     * @return
+     * @param basePort base port to start
+     * @return new socket with available port
      */
     private static ServerSocket getServerSocketFromBasePort(int basePort) {
         int tryCount = 0;
@@ -229,7 +228,7 @@ public class SimpleHttpCommandCenter implements CommandCenter {
         }
 
         if (handlerMap.containsKey(commandName)) {
-            CommandCenterLog.info("Register failed (duplicate command): " + commandName);
+            CommandCenterLog.warn("Register failed (duplicate command): " + commandName);
             return;
         }