for #2441, refactor Limit's constructor

sharding-core/sharding-core-route/src/main/java/org/apache/shardingsphere/core/route/limit/Limit.java

@@ -19,7 +19,6 @@ package org.apache.shardingsphere.core.route.limit;
 
 import lombok.Getter;
 import lombok.ToString;
-import org.apache.shardingsphere.core.parse.exception.SQLParsingException;
 import org.apache.shardingsphere.core.util.NumberUtil;
 
 import java.util.HashMap;
@@ -37,30 +36,19 @@ import java.util.Map;
 @ToString
 public final class Limit {
     
-    private LimitValue offset;
+    private final LimitValue offset;
     
-    private LimitValue rowCount;
+    private final LimitValue rowCount;
     
     public Limit(final LimitValue offset, final LimitValue rowCount, final List<Object> parameters) {
-        this.offset = offset;
-        this.rowCount = rowCount;
-        fillParameters(parameters);
-    }
-    
-    private void fillParameters(final List<Object> parameters) {
-        int offset = 0;
-        if (null != this.offset) {
-            offset = -1 == this.offset.getIndex() ? getOffsetValue() : NumberUtil.roundHalfUp(parameters.get(this.offset.getIndex()));
-            this.offset.setValue(offset);
+        if (null != offset) {
+            offset.setValue(-1 == offset.getIndex() ? getOffsetValue() : NumberUtil.roundHalfUp(parameters.get(offset.getIndex())));
         }
-        int rowCount = 0;
-        if (null != this.rowCount) {
-            rowCount = -1 == this.rowCount.getIndex() ? getRowCountValue() : NumberUtil.roundHalfUp(parameters.get(this.rowCount.getIndex()));
-            this.rowCount.setValue(rowCount);
-        }
-        if (offset < 0 || rowCount < 0) {
-            throw new SQLParsingException("LIMIT offset and row count can not be a negative value.");
+        this.offset = offset;
+        if (null != rowCount) {
+            rowCount.setValue(-1 == rowCount.getIndex() ? getRowCountValue() : NumberUtil.roundHalfUp(parameters.get(rowCount.getIndex())));
         }
+        this.rowCount = rowCount;
     }
     
     /**