Implemented issue: #82

jse/src/main/java/org/luaj/vm2/libs/jse/JavaClass.java

@@ -56,6 +56,10 @@ class JavaClass extends JavaInstance implements CoerceJavaToLua.Coercion {
 	Map methods;
 	Map innerclasses;
 
+	static void flushClassCache() {
+		classes.clear();
+	}
+
 	static JavaClass forClass(Class c) {
 		JavaClass j = (JavaClass) classes.get(c);
 		if ( j == null )
@@ -75,10 +79,11 @@ class JavaClass extends JavaInstance implements CoerceJavaToLua.Coercion {
 	Field getField(LuaValue key) {
 		if ( fields == null ) {
 			Map m = new HashMap();
-			Field[] f = ((Class)m_instance).getFields();
+			Class clazz = (Class) m_instance;
+			Field[] f = clazz.getFields();
 			for ( int i=0; i<f.length; i++ ) {
 				Field fi = f[i];
-				if ( Modifier.isPublic(fi.getModifiers()) ) {
+				if ( Modifier.isPublic(fi.getModifiers()) && LuajavaLib.isFieldVisible(clazz, fi) ) {
 					m.put(LuaValue.valueOf(fi.getName()), fi);
 					try {
 						if (!fi.isAccessible())
@@ -95,10 +100,11 @@ class JavaClass extends JavaInstance implements CoerceJavaToLua.Coercion {
 	LuaValue getMethod(LuaValue key) {
 		if ( methods == null ) {
 			Map namedlists = new HashMap();
-			Method[] m = ((Class)m_instance).getMethods();
+			Class clazz = (Class) m_instance;
+			Method[] m = clazz.getMethods();
 			for ( int i=0; i<m.length; i++ ) {
 				Method mi = m[i];
-				if ( Modifier.isPublic( mi.getModifiers()) ) {
+				if ( Modifier.isPublic( mi.getModifiers()) && LuajavaLib.isMethodVisible(clazz, mi) ) {
 					String name = mi.getName();
 					List list = (List) namedlists.get(name);
 					if ( list == null )
@@ -107,10 +113,10 @@ class JavaClass extends JavaInstance implements CoerceJavaToLua.Coercion {
 				}
 			}
 			Map map = new HashMap();
-			Constructor[] c = ((Class)m_instance).getConstructors();
+			Constructor[] c = clazz.getConstructors();
 			List list = new ArrayList();
 			for ( int i=0; i<c.length; i++ ) 
-				if ( Modifier.isPublic(c[i].getModifiers()) )
+				if ( Modifier.isPublic(c[i].getModifiers()) && LuajavaLib.isConstructorVisible(clazz, c[i]) )
 					list.add( JavaConstructor.forConstructor(c[i]) );
 			switch ( list.size() ) {
 			case 0: break;
@@ -135,13 +141,16 @@ class JavaClass extends JavaInstance implements CoerceJavaToLua.Coercion {
 	Class getInnerClass(LuaValue key) {
 		if ( innerclasses == null ) {
 			Map m = new HashMap();
-			Class[] c = ((Class)m_instance).getClasses();
+			Class clazz = (Class) m_instance;
+			Class[] c = clazz.getClasses();
 			for ( int i=0; i<c.length; i++ ) {
 				Class ci = c[i];
+				if (LuajavaLib.isInnerClassVisible(clazz, ci)) {
 					String name = ci.getName();
 					String stub = name.substring(Math.max(name.lastIndexOf('$'), name.lastIndexOf('.'))+1);
 					m.put(LuaValue.valueOf(stub), ci);
 				}
+			}
 			innerclasses = m;
 		}
 		return (Class) innerclasses.get(key);

jse/src/main/java/org/luaj/vm2/libs/jse/LuajavaLib.java

@@ -23,6 +23,8 @@ package org.luaj.vm2.libs.jse;
 
 
 import java.lang.reflect.Array;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
@@ -83,6 +85,38 @@ import org.luaj.vm2.libs.VarArgFunction;
  */
 public class LuajavaLib extends VarArgFunction {
 
+	public interface VisibilityPolicy {
+		boolean isClassVisible(Class clazz);
+		boolean isInnerClassVisible(Class owner, Class innerClass);
+		boolean isFieldVisible(Class owner, Field field);
+		boolean isMethodVisible(Class owner, Method method);
+		boolean isConstructorVisible(Class owner, Constructor constructor);
+	}
+
+	private static final VisibilityPolicy PUBLIC_MEMBERS_POLICY = new VisibilityPolicy() {
+		public boolean isClassVisible(Class clazz) {
+			return true;
+		}
+
+		public boolean isInnerClassVisible(Class owner, Class innerClass) {
+			return true;
+		}
+
+		public boolean isFieldVisible(Class owner, Field field) {
+			return true;
+		}
+
+		public boolean isMethodVisible(Class owner, Method method) {
+			return true;
+		}
+
+		public boolean isConstructorVisible(Class owner, Constructor constructor) {
+			return true;
+		}
+	};
+
+	private static volatile VisibilityPolicy visibilityPolicy = PUBLIC_MEMBERS_POLICY;
+
 	static final int INIT           = 0;
 	static final int BINDCLASS      = 1;
 	static final int NEWINSTANCE	= 2;
@@ -103,6 +137,35 @@ public class LuajavaLib extends VarArgFunction {
 	public LuajavaLib() {
 	}
 
+	public static void setVisibilityPolicy(VisibilityPolicy policy) {
+		visibilityPolicy = policy != null ? policy : PUBLIC_MEMBERS_POLICY;
+		JavaClass.flushClassCache();
+	}
+
+	public static VisibilityPolicy getVisibilityPolicy() {
+		return visibilityPolicy;
+	}
+
+	static boolean isClassVisible(Class clazz) {
+		return visibilityPolicy.isClassVisible(clazz);
+	}
+
+	static boolean isInnerClassVisible(Class owner, Class innerClass) {
+		return visibilityPolicy.isInnerClassVisible(owner, innerClass);
+	}
+
+	static boolean isFieldVisible(Class owner, Field field) {
+		return visibilityPolicy.isFieldVisible(owner, field);
+	}
+
+	static boolean isMethodVisible(Class owner, Method method) {
+		return visibilityPolicy.isMethodVisible(owner, method);
+	}
+
+	static boolean isConstructorVisible(Class owner, Constructor constructor) {
+		return visibilityPolicy.isConstructorVisible(owner, constructor);
+	}
+
 	public Varargs invoke(Varargs args) {
 		try {
 			switch ( opcode ) {
@@ -117,6 +180,8 @@ public class LuajavaLib extends VarArgFunction {
 			}
 			case BINDCLASS: {
 				final Class clazz = classForName(args.checkjstring(1));
+				if (!isClassVisible(clazz))
+					throw new LuaError("class is not visible: " + clazz.getName());
 				return JavaClass.forClass(clazz);
 			}
 			case NEWINSTANCE:
@@ -124,6 +189,8 @@ public class LuajavaLib extends VarArgFunction {
 				// get constructor
 				final LuaValue c = args.checkvalue(1);
 				final Class clazz = (opcode==NEWINSTANCE? classForName(c.tojstring()): (Class) c.checkuserdata(Class.class));
+				if (!isClassVisible(clazz))
+					throw new LuaError("class is not visible: " + clazz.getName());
 				final Varargs consargs = args.subargs(2);
 				return JavaClass.forClass(clazz).getConstructor().invoke(consargs);
 			}
@@ -175,7 +242,10 @@ public class LuajavaLib extends VarArgFunction {
 
 	// load classes using app loader to allow luaj to be used as an extension
 	protected Class classForName(String name) throws ClassNotFoundException {
-		return Class.forName(name, true, ClassLoader.getSystemClassLoader());
+		Class clazz = Class.forName(name, true, ClassLoader.getSystemClassLoader());
+		if (!isClassVisible(clazz))
+			throw new ClassNotFoundException("class is not visible: " + name);
+		return clazz;
 	}
 	
 	private static final class ProxyInvocationHandler implements InvocationHandler {

jse/src/test/java/org/luaj/vm2/libs/jse/LuajavaClassMembersTest.java

@@ -1,5 +1,9 @@
 package org.luaj.vm2.libs.jse;
 
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+
 import junit.framework.TestCase;
 
 import org.luaj.vm2.LuaError;
@@ -235,4 +239,49 @@ public class LuajavaClassMembersTest extends TestCase {
 		LuaValue e = ic.get("E");
 		assertTrue(e.isnil());
 	}
+
+	public void testVisibilityPolicyCanRestrictVisibleMembers() {
+		LuajavaLib.VisibilityPolicy previous = LuajavaLib.getVisibilityPolicy();
+		try {
+			LuajavaLib.setVisibilityPolicy(new LuajavaLib.VisibilityPolicy() {
+				public boolean isClassVisible(Class clazz) {
+					return clazz == B.class || clazz == C.class || clazz == C.D.class;
+				}
+
+				public boolean isInnerClassVisible(Class owner, Class innerClass) {
+					return innerClass == C.D.class;
+				}
+
+				public boolean isFieldVisible(Class owner, Field field) {
+					return "m_int_field".equals(field.getName());
+				}
+
+				public boolean isMethodVisible(Class owner, Method method) {
+					String name = method.getName();
+					return "getint".equals(name) || "pick".equals(name);
+				}
+
+				public boolean isConstructorVisible(Class owner, Constructor constructor) {
+					return owner == B.class && constructor.getParameterTypes().length == 0;
+				}
+			});
+
+			JavaInstance instance = new JavaInstance(new B());
+			assertFalse(instance.get("m_int_field").isnil());
+			assertTrue(instance.get("m_string_field").isnil());
+			assertFalse(instance.get("getint").isnil());
+			assertTrue(instance.get("getString").isnil());
+
+			JavaClass bClass = JavaClass.forClass(B.class);
+			assertFalse(bClass.get("new").isnil());
+
+			JavaClass cClass = JavaClass.forClass(C.class);
+			assertTrue(cClass.get("new").isnil());
+
+			JavaInstance cInstance = new JavaInstance(new C());
+			assertFalse(cInstance.get("D").isnil());
+		} finally {
+			LuajavaLib.setVisibilityPolicy(previous);
+		}
+	}
 }