fixed issue #782 , 重复了exception

parse/src/main/java/com/alibaba/otter/canal/parse/inbound/mysql/MysqlMultiStageCoprocessor.java

@@ -4,7 +4,6 @@ import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.locks.LockSupport;
 
-import com.alibaba.otter.canal.common.CanalException;
 import org.apache.commons.lang.StringUtils;
 
 import com.alibaba.otter.canal.common.AbstractCanalLifeCycle;
@@ -64,7 +63,6 @@ public class MysqlMultiStageCoprocessor extends AbstractCanalLifeCycle implement
     private ExecutorService              stageExecutor;
     private String                       destination;
     private volatile CanalParseException exception;
-    private volatile RuntimeException    incident;
 
     public MysqlMultiStageCoprocessor(int ringBufferSize, int parserThreadCount, LogEventConvert logEventConvert,
                                       EventTransactionBuffer transactionBuffer, String destination){
@@ -79,7 +77,6 @@ public class MysqlMultiStageCoprocessor extends AbstractCanalLifeCycle implement
     public void start() {
         super.start();
         this.exception = null;
-        this.incident = null;
         this.disruptorMsgBuffer = RingBuffer.createSingleProducer(new MessageEventFactory(),
             ringBufferSize,
             new BlockingWaitStrategy());
@@ -156,13 +153,13 @@ public class MysqlMultiStageCoprocessor extends AbstractCanalLifeCycle implement
             return false;
         }
 
-        /* 由于改为processor仅终止自身stage而不是stop，那么需要由incident标识coprocessor是否正常工作。
+        /**
+         * 由于改为processor仅终止自身stage而不是stop，那么需要由incident标识coprocessor是否正常工作。
          * 让dump线程能够及时感知
          */
-        if (incident != null) {
-            throw incident;
+        if (exception != null) {
+            throw exception;
         }
-
         boolean interupted = false;
         do {
             try {
@@ -180,11 +177,6 @@ public class MysqlMultiStageCoprocessor extends AbstractCanalLifeCycle implement
                 interupted = Thread.interrupted();
             }
         } while (!interupted && isStart());
-
-        if (exception != null) {
-            throw exception;
-        }
-
         return isStart();
     }
 
@@ -405,12 +397,6 @@ public class MysqlMultiStageCoprocessor extends AbstractCanalLifeCycle implement
 
         @Override
         public void handleEventException(final Throwable ex, final long sequence, final Object event) {
-            /*
-             * 若异常不是onEvent body里产生的。如果仅仅抛出去，onShutdown会调用stop()，与dump线程的reset()产生竞争，导致向terminated ExecutorService提交新task
-             * #771场景中的异常是InterruptedException，由shutdownNow产生。
-             */
-            incident = new RuntimeException(ex);
-            throw incident;
         }
 
         @Override