SCB-1696 Refactoring duplicate code
diff --git a/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/SagaAbortedEvent.java b/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/SagaAbortedEvent.java
index d73f4bb..343cb67 100644
--- a/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/SagaAbortedEvent.java
+++ b/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/SagaAbortedEvent.java
@@ -17,26 +17,12 @@
 
 package org.apache.servicecomb.pack.omega.transaction;
 
-import java.io.PrintWriter;
-import java.io.StringWriter;
 import org.apache.servicecomb.pack.common.EventType;
 
 public class SagaAbortedEvent extends TxEvent {
 
-  private static final int PAYLOADS_MAX_LENGTH = 10240;
-
   public SagaAbortedEvent(String globalTxId, String localTxId, String parentTxId, String compensationMethod, Throwable throwable) {
     super(EventType.SagaAbortedEvent, globalTxId, localTxId, parentTxId, compensationMethod, 0, "", 0,
         0, 0, 0, 0, stackTrace(throwable));
   }
-
-  private static String stackTrace(Throwable e) {
-    StringWriter writer = new StringWriter();
-    e.printStackTrace(new PrintWriter(writer));
-    String stackTrace = writer.toString();
-    if (stackTrace.length() > PAYLOADS_MAX_LENGTH) {
-      stackTrace = stackTrace.substring(0, PAYLOADS_MAX_LENGTH);
-    }
-    return stackTrace;
-  }
 }
\ No newline at end of file
diff --git a/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxAbortedEvent.java b/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxAbortedEvent.java
index 9a3d555..fe0818d 100644
--- a/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxAbortedEvent.java
+++ b/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxAbortedEvent.java
@@ -17,27 +17,12 @@
 
 package org.apache.servicecomb.pack.omega.transaction;
 
-import java.io.PrintWriter;
-import java.io.StringWriter;
-
 import org.apache.servicecomb.pack.common.EventType;
 
 public class TxAbortedEvent extends TxEvent {
 
-  private static final int PAYLOADS_MAX_LENGTH = 10240;
-
   public TxAbortedEvent(String globalTxId, String localTxId, String parentTxId, String compensationMethod, Throwable throwable) {
     super(EventType.TxAbortedEvent, globalTxId, localTxId, parentTxId, compensationMethod, 0, "", 0,
         0, 0, 0, 0, stackTrace(throwable));
   }
-
-  private static String stackTrace(Throwable e) {
-    StringWriter writer = new StringWriter();
-    e.printStackTrace(new PrintWriter(writer));
-    String stackTrace = writer.toString();
-    if (stackTrace.length() > PAYLOADS_MAX_LENGTH) {
-      stackTrace = stackTrace.substring(0, PAYLOADS_MAX_LENGTH);
-    }
-    return stackTrace;
-  }
 }
diff --git a/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxEvent.java b/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxEvent.java
index b7dabaa..4cab583 100644
--- a/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxEvent.java
+++ b/omega/omega-transaction/src/main/java/org/apache/servicecomb/pack/omega/transaction/TxEvent.java
@@ -17,12 +17,14 @@
 
 package org.apache.servicecomb.pack.omega.transaction;
 
+import java.io.PrintWriter;
+import java.io.StringWriter;
 import java.util.Arrays;
 
 import org.apache.servicecomb.pack.common.EventType;
 
 public class TxEvent {
-
+  protected static final int PAYLOADS_MAX_LENGTH = 10240;
   private final long timestamp;
   private final EventType type;
   private final String globalTxId;
@@ -131,4 +133,14 @@
         ", payloads=" + Arrays.toString(payloads) +
         '}';
   }
+
+  protected static String stackTrace(Throwable e) {
+    StringWriter writer = new StringWriter();
+    e.printStackTrace(new PrintWriter(writer));
+    String stackTrace = writer.toString();
+    if (stackTrace.length() > PAYLOADS_MAX_LENGTH) {
+      stackTrace = stackTrace.substring(0, PAYLOADS_MAX_LENGTH);
+    }
+    return stackTrace;
+  }
 }