make canal server become a single instance

deployer/src/main/java/com/alibaba/otter/canal/deployer/CanalController.java

@@ -88,9 +88,9 @@ public class CanalController {
         cid = Long.valueOf(getProperty(properties, CanalConstants.CANAL_ID));
         ip = getProperty(properties, CanalConstants.CANAL_IP);
         port = Integer.valueOf(getProperty(properties, CanalConstants.CANAL_PORT));
-        embededCanalServer = new CanalServerWithEmbedded();
+        embededCanalServer = CanalServerWithEmbedded.instance();
         embededCanalServer.setCanalInstanceGenerator(instanceGenerator);// 设置自定义的instanceGenerator
-        canalServer = new CanalServerWithNetty(embededCanalServer);
+        canalServer = CanalServerWithNetty.instance();
         canalServer.setIp(ip);
         canalServer.setPort(port);
 

server/src/main/java/com/alibaba/otter/canal/server/embedded/CanalServerWithEmbedded.java

@@ -6,6 +6,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 
+import com.alibaba.otter.canal.server.CanalService;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.MDC;
@@ -37,24 +38,39 @@ import com.google.common.collect.MigrateMap;
  * @author zebin.xuzb
  * @version 1.0.0
  */
-public class CanalServerWithEmbedded extends AbstractCanalLifeCycle implements CanalServer, com.alibaba.otter.canal.server.CanalService {
+public class CanalServerWithEmbedded extends AbstractCanalLifeCycle implements CanalServer, CanalService {
 
     private static final Logger        logger = LoggerFactory.getLogger(CanalServerWithEmbedded.class);
     private Map<String, CanalInstance> canalInstances;
     // private Map<ClientIdentity, Position> lastRollbackPostions;
     private CanalInstanceGenerator     canalInstanceGenerator;
 
+
+    private static class SingletonHolder {
+        private static final CanalServerWithEmbedded CANAL_SERVER_WITH_EMBEDDED = new CanalServerWithEmbedded();
+    }
+
+    private CanalServerWithEmbedded() {
+
+    }
+
+    public static CanalServerWithEmbedded instance() {
+        return SingletonHolder.CANAL_SERVER_WITH_EMBEDDED;
+    }
+
     public void start() {
-        super.start();
+        if (!isStart()) {
+            super.start();
 
-        canalInstances = MigrateMap.makeComputingMap(new Function<String, CanalInstance>() {
+            canalInstances = MigrateMap.makeComputingMap(new Function<String, CanalInstance>() {
 
-            public CanalInstance apply(String destination) {
-                return canalInstanceGenerator.generate(destination);
-            }
-        });
+                public CanalInstance apply(String destination) {
+                    return canalInstanceGenerator.generate(destination);
+                }
+            });
 
-        // lastRollbackPostions = new MapMaker().makeMap();
+            // lastRollbackPostions = new MapMaker().makeMap();
+        }
     }
 
     public void stop() {

server/src/main/java/com/alibaba/otter/canal/server/netty/CanalServerWithNetty.java

@@ -33,11 +33,16 @@ public class CanalServerWithNetty extends AbstractCanalLifeCycle implements Cana
     private Channel                 serverChannel = null;
     private ServerBootstrap         bootstrap     = null;
 
-    public CanalServerWithNetty(){
+    private static class SingletonHolder {
+        private static final CanalServerWithNetty CANAL_SERVER_WITH_NETTY = new CanalServerWithNetty();
     }
 
-    public CanalServerWithNetty(CanalServerWithEmbedded embeddedServer){
-        this.embeddedServer = embeddedServer;
+    private CanalServerWithNetty(){
+        this.embeddedServer = CanalServerWithEmbedded.instance();
+    }
+
+    public static CanalServerWithNetty instance() {
+        return SingletonHolder.CANAL_SERVER_WITH_NETTY;
     }
 
     public void start() {
@@ -98,8 +103,4 @@ public class CanalServerWithNetty extends AbstractCanalLifeCycle implements Cana
         this.port = port;
     }
 
-    public void setEmbeddedServer(CanalServerWithEmbedded embeddedServer) {
-        this.embeddedServer = embeddedServer;
-    }
-
 }

server/src/test/java/com/alibaba/otter/canal/server/BaseCanalServerWithEmbededTest.java

@@ -31,7 +31,7 @@ public abstract class BaseCanalServerWithEmbededTest {
 
     @Before
     public void setUp() {
-        server = new CanalServerWithEmbedded();
+        server = CanalServerWithEmbedded.instance();
         server.setCanalInstanceGenerator(new CanalInstanceGenerator() {
 
             public CanalInstance generate(String destination) {

server/src/test/java/com/alibaba/otter/canal/server/CanalServerWithNettyTest.java

@@ -49,7 +49,7 @@ public class CanalServerWithNettyTest {
 
     @Before
     public void setUp() {
-        CanalServerWithEmbedded embeddedServer = new CanalServerWithEmbedded();
+        CanalServerWithEmbedded embeddedServer = CanalServerWithEmbedded.instance();
         embeddedServer.setCanalInstanceGenerator(new CanalInstanceGenerator() {
 
             public CanalInstance generate(String destination) {