bug fixed for dataSource.restart()

src/main/java/com/alibaba/druid/pool/DruidDataSource.java

@@ -286,9 +286,12 @@ public class DruidDataSource extends DruidAbstractDataSource implements DruidDat
         return discardCount;
     }
 
-    public void restart() {
+    public void restart() throws SQLException {
         lock.lock();
         try {
+            if (activeCount > 0) {
+                throw new SQLException("can not restart, activeCount not zero. " + activeCount);
+            }
             if (LOG.isInfoEnabled()) {
                 LOG.info("{dataSource-" + this.getID() + "} restart");
             }

src/test/java/com/alibaba/druid/bvt/pool/DruidDataSourceTest.java

@@ -1,9 +1,11 @@
 package com.alibaba.druid.bvt.pool;
 
 import java.sql.Connection;
+import java.sql.SQLException;
+
+import junit.framework.TestCase;
 
 import org.junit.Assert;
-import junit.framework.TestCase;
 
 import com.alibaba.druid.pool.DruidDataSource;
 
@@ -22,17 +24,34 @@ public class DruidDataSourceTest extends TestCase {
     protected void tearDown() throws Exception {
         dataSource.close();
     }
-    
+
     public void test_getInitStackTrace() {
         String stackTrace = dataSource.getInitStackTrace();
         Assert.assertTrue(stackTrace.indexOf("com.alibaba.druid.bvt.pool.DruidDataSourceTest.setUp") != -1);
     }
-    
+
     public void test_restart() throws Exception {
         Assert.assertEquals(true, dataSource.isInited());
-        dataSource.restart();
+        {
+            Connection conn = dataSource.getConnection();
+            Assert.assertEquals(1, dataSource.getActiveCount());
+
+            Exception error = null;
+            try {
+                dataSource.restart();
+            } catch (SQLException ex) {
+                error = ex;
+            }
+            Assert.assertNotNull(error);
+            Assert.assertEquals(true, dataSource.isInited());
+
+            conn.close();
+            dataSource.restart();
+        }
+
+        Assert.assertEquals(0, dataSource.getActiveCount());
         Assert.assertEquals(false, dataSource.isInited());
-        
+
         Connection conn = dataSource.getConnection();
         conn.close();
     }