0006203: Added hashCode() method to TriggerHistory to fix selection o…

…n Manage Installed Triggers Screen

symmetric-core/src/main/java/org/jumpmind/symmetric/model/TriggerHistory.java

@@ -344,6 +344,14 @@ protected String[] parseColumnNames(String argColumnNames) {
         }
     }
 
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + triggerHistoryId;
+        return result;
+    }
+
     @Override
     public boolean equals(Object obj) {
         return obj != null && obj instanceof TriggerHistory && ((TriggerHistory) obj).triggerHistoryId == triggerHistoryId;