add clob open stat support

src/main/java/com/alibaba/druid/filter/stat/StatFilter.java

@@ -822,6 +822,8 @@ public class StatFilter extends FilterEventAdapter implements StatFilterMBean {
 
     private void clobOpenAfter(JdbcDataSourceStat dataSourceStat, ClobProxy clob) {
         dataSourceStat.incrementClobOpenCount();
+
+        StatFilterContext.getInstance().clob_open();
     }
 
     @Override
@@ -830,6 +832,8 @@ public class StatFilter extends FilterEventAdapter implements StatFilterMBean {
 
         JdbcDataSourceStat dataSourceStat = chain.getDataSource().getDataSourceStat();
         dataSourceStat.incrementClobFreeCount();
+
+        StatFilterContext.getInstance().clob_free();
     }
 
 }

src/main/java/com/alibaba/druid/filter/stat/StatFilterContext.java

@@ -110,10 +110,16 @@ public class StatFilterContext {
     }
 
     public void clob_open() {
-
+        for (int i = 0; i < listeners.size(); ++i) {
+            StatFilterContextListener listener = listeners.get(i);
+            listener.clob_open();
+        }
     }
 
-    public void clobFree() {
-
+    public void clob_free() {
+        for (int i = 0; i < listeners.size(); ++i) {
+            StatFilterContextListener listener = listeners.get(i);
+            listener.clob_free();
+        }
     }
 }

src/main/java/com/alibaba/druid/filter/stat/StatFilterContextListener.java

@@ -25,4 +25,8 @@ public interface StatFilterContextListener {
     void resultSet_open();
     
     void resultSet_close(long nanos);
+    
+    void clob_open();
+    
+    void clob_free();
 }

src/main/java/com/alibaba/druid/filter/stat/StatFilterContextListenerAdapter.java

@@ -62,5 +62,15 @@ public class StatFilterContextListenerAdapter implements StatFilterContextListen
         
     }
 
+    @Override
+    public void clob_open() {
+        
+    }
+
+    @Override
+    public void clob_free() {
+        
+    }
+
     
 }