improve WallFilter, support intersectAllow

src/main/java/com/alibaba/druid/wall/WallConfig.java

@@ -45,6 +45,7 @@ public class WallConfig implements WallConfigMBean {
     private boolean             insertAllow                = true;
     private boolean             mergeAllow                 = true;
     private boolean             minusAllow                 = false;
+    private boolean             intersectAllow                  = false;
 
     private boolean             multiStatementAllow        = false;
 
@@ -91,10 +92,18 @@ public class WallConfig implements WallConfigMBean {
 
     }
     
+    public boolean isIntersectAllow() {
+        return intersectAllow;
+    }
+    
+    public void setIntersectAllow(boolean intersectAllow) {
+        this.intersectAllow = intersectAllow;
+    }
+
     public boolean isMinusAllow() {
         return minusAllow;
     }
-    
+
     public void setMinusAllow(boolean minusAllow) {
         this.minusAllow = minusAllow;
     }

src/main/java/com/alibaba/druid/wall/spi/WallVisitorUtils.java

@@ -753,6 +753,11 @@ public class WallVisitorUtils {
             return;
         }
 
+        if (x.getOperator() == SQLUnionOperator.INTERSECT && !visitor.getConfig().isIntersectAllow()) {
+            addViolation(visitor, x);
+            return;
+        }
+
         if (!visitor.getConfig().isSelectUnionCheck()) {
             return;
         }

src/test/java/com/alibaba/druid/bvt/filter/wall/IntersectTest.java

@@ -0,0 +1,23 @@
+package com.alibaba.druid.bvt.filter.wall;
+
+import junit.framework.TestCase;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.wall.WallConfig;
+import com.alibaba.druid.wall.WallUtils;
+
+public class IntersectTest extends TestCase {
+
+    public void test_false() throws Exception {
+        Assert.assertFalse(WallUtils.isValidateOracle(//
+        "SELECT * FROM A MINUS SELECT * FROM B")); //
+    }
+
+    public void test_true() throws Exception {
+        WallConfig config = new WallConfig();
+        config.setMinusAllow(true);
+        Assert.assertTrue(WallUtils.isValidateOracle(//
+        "SELECT * FROM A MINUS SELECT * FROM B", config)); //
+    }
+}

src/test/java/com/alibaba/druid/bvt/filter/wall/MinusTest.java

@@ -11,13 +11,13 @@ public class MinusTest extends TestCase {
 
     public void test_false() throws Exception {
         Assert.assertFalse(WallUtils.isValidateOracle(//
-        "SELECT * FROM A MINUS SELECT * FROM B")); //
+        "SELECT * FROM A Intersect SELECT * FROM B")); //
     }
 
     public void test_true() throws Exception {
         WallConfig config = new WallConfig();
-        config.setMinusAllow(true);
+        config.setIntersectAllow(true);
         Assert.assertTrue(WallUtils.isValidateOracle(//
-        "SELECT * FROM A MINUS SELECT * FROM B", config)); //
+        "SELECT * FROM A Intersect SELECT * FROM B", config)); //
     }
 }