import otherpackage.OtherPackageClass; import java.io.Serializable; import java.lang.reflect.AccessibleObject; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.lang.reflect.Modifier; import java.lang.reflect.Type; import java.lang.reflect.TypeVariable; import java.util.ArrayList; import java.util.Collections; import java.util.List; public class ClassAttrs { ClassAttrs() { /* local, not anonymous, not member */ class ConsInnerNamed { public void showMe() { printClassAttrs(this.getClass()); } } ConsInnerNamed cinner = new ConsInnerNamed(); cinner.showMe(); } public class PublicInnerClass { } protected class ProtectedInnerClass { } private class PrivateInnerClass { } class PackagePrivateInnerClass { } public interface PublicInnerInterface { } protected interface ProtectedInnerInterface { } private interface PrivateInnerInterface { } interface PackagePrivateInnerInterface { } private static void showModifiers(Class<?> c) { System.out.println(Modifier.toString(c.getModifiers()) + " " + c.getName()); } // https://code.google.com/p/android/issues/detail?id=56267 private static void test56267() { // Primitive classes. showModifiers(int.class); showModifiers(int[].class); // Regular classes. showModifiers(Object.class); showModifiers(Object[].class); // Inner classes. showModifiers(PublicInnerClass.class); showModifiers(PublicInnerClass[].class); showModifiers(ProtectedInnerClass.class); showModifiers(ProtectedInnerClass[].class); showModifiers(PrivateInnerClass.class); showModifiers(PrivateInnerClass[].class); showModifiers(PackagePrivateInnerClass.class); showModifiers(PackagePrivateInnerClass[].class); // Regular interfaces. showModifiers(Serializable.class); showModifiers(Serializable[].class); // Inner interfaces. showModifiers(PublicInnerInterface.class); showModifiers(PublicInnerInterface[].class); showModifiers(ProtectedInnerInterface.class); showModifiers(ProtectedInnerInterface[].class); showModifiers(PrivateInnerInterface.class); showModifiers(PrivateInnerInterface[].class); showModifiers(PackagePrivateInnerInterface.class); showModifiers(PackagePrivateInnerInterface[].class); } public static void main() { test56267(); printClassAttrs(ClassAttrs.class); printClassAttrs(OtherClass.class); printClassAttrs(OtherPackageClass.class); /* local, not anonymous, not member */ class InnerNamed { public void showMe() { printClassAttrs(this.getClass()); } } InnerNamed inner = new InnerNamed(); inner.showMe(); ClassAttrs attrs = new ClassAttrs(); /* anonymous, not local, not member */ printClassAttrs((new OtherClass() { int i = 5; }).getClass()); /* member, not anonymous, not local */ printClassAttrs(MemberClass.class); /* fancy */ printClassAttrs(FancyClass.class); try { Constructor cons; cons = MemberClass.class.getConstructor( new Class[] { MemberClass.class }); System.out.println("constructor signature: " + getSignatureAttribute(cons)); Method meth; meth = MemberClass.class.getMethod("foo", (Class[]) null); System.out.println("method signature: " + getSignatureAttribute(meth)); Field field; field = MemberClass.class.getField("mWha"); System.out.println("field signature: " + getSignatureAttribute(field)); } catch (NoSuchMethodException nsme) { System.err.println("FAILED: " + nsme); } catch (NoSuchFieldException nsfe) { System.err.println("FAILED: " + nsfe); } catch (RuntimeException re) { System.err.println("FAILED: " + re); re.printStackTrace(); } test_isAssignableFrom(); test_isInstance(); } private static void test_isAssignableFrom() { // Can always assign to things of the same type. assertTrue(String.class.isAssignableFrom(String.class)); // Can assign any reference to java.lang.Object. assertTrue(Object.class.isAssignableFrom(Object.class)); assertTrue(Object.class.isAssignableFrom(Class.class)); assertTrue(Object.class.isAssignableFrom(String.class)); assertFalse(Object.class.isAssignableFrom(int.class)); assertFalse(Object.class.isAssignableFrom(long.class)); // Interfaces. assertTrue(CharSequence.class.isAssignableFrom(String.class)); assertFalse(CharSequence.class.isAssignableFrom(Object.class)); // Superclasses. assertTrue(AccessibleObject.class.isAssignableFrom(Method.class)); assertFalse(Method.class.isAssignableFrom(AccessibleObject.class)); // Arrays. assertTrue(int[].class.isAssignableFrom(int[].class)); assertFalse(int[].class.isAssignableFrom(char[].class)); assertFalse(char[].class.isAssignableFrom(int[].class)); assertTrue(Object.class.isAssignableFrom(int[].class)); assertFalse(int[].class.isAssignableFrom(Object.class)); try { assertFalse(Object.class.isAssignableFrom(null)); fail(); } catch (NullPointerException expected) { } } private static void test_isInstance() { // Can always assign to things of the same type. assertTrue(String.class.isInstance("hello")); // Can assign any reference to java.lang.Object. assertTrue(Object.class.isInstance(new Object())); assertTrue(Object.class.isInstance(Class.class)); assertTrue(Object.class.isInstance("hello")); // Interfaces. assertTrue(CharSequence.class.isInstance("hello")); assertFalse(CharSequence.class.isInstance(new Object())); // Superclasses. assertTrue(AccessibleObject.class.isInstance(Method.class.getDeclaredMethods()[0])); assertFalse(Method.class.isInstance(Method.class.getDeclaredFields()[0])); // Arrays. assertTrue(int[].class.isInstance(new int[0])); assertFalse(int[].class.isInstance(new char[0])); assertFalse(char[].class.isInstance(new int[0])); assertTrue(Object.class.isInstance(new int[0])); assertFalse(int[].class.isInstance(new Object())); assertFalse(Object.class.isInstance(null)); } private static void assertTrue(boolean b) { if (!b) throw new RuntimeException(); } private static void assertFalse(boolean b) { if (b) throw new RuntimeException(); } private static void fail() { throw new RuntimeException(); } /* to call the (out-of-scope) <code>getSignatureAttribute</code> methods */ public static String getSignatureAttribute(Object obj) { Method method; try { Class c = Class.forName("libcore.reflect.AnnotationAccess"); method = c.getDeclaredMethod("getSignature", java.lang.reflect.AnnotatedElement.class); method.setAccessible(true); } catch (Exception ex) { ex.printStackTrace(); return "<unknown>"; } try { return (String) method.invoke(null, obj); } catch (IllegalAccessException ex) { throw new RuntimeException(ex); } catch (InvocationTargetException ex) { throw new RuntimeException(ex); } } /* for reflection testing */ static class MemberClass<XYZ> { public MemberClass<XYZ> mWha; public MemberClass(MemberClass<XYZ> memb) { mWha = memb; } public Class<XYZ> foo() throws NoSuchMethodException { return null; } } /* for reflection testing (getClasses vs getDeclaredClasses) */ static public class PublicMemberClass { float mBlah; } /* * Dump a variety of class attributes. */ public static void printClassAttrs(Class clazz) { Class clazz2; System.out.println("***** " + clazz + ":"); System.out.println(" name: " + clazz.getName()); System.out.println(" canonical: " + clazz.getCanonicalName()); System.out.println(" simple: " + clazz.getSimpleName()); System.out.println(" genericSignature: " + getSignatureAttribute(clazz)); System.out.println(" super: " + clazz.getSuperclass()); System.out.println(" genericSuperclass: " + clazz.getGenericSuperclass()); System.out.println(" declaring: " + clazz.getDeclaringClass()); System.out.println(" enclosing: " + clazz.getEnclosingClass()); System.out.println(" enclosingCon: " + clazz.getEnclosingConstructor()); System.out.println(" enclosingMeth: " + clazz.getEnclosingMethod()); System.out.println(" modifiers: " + clazz.getModifiers()); System.out.println(" package: " + clazz.getPackage()); System.out.println(" declaredClasses: " + stringifyTypeArray(clazz.getDeclaredClasses())); System.out.println(" member classes: " + stringifyTypeArray(clazz.getClasses())); System.out.println(" isAnnotation: " + clazz.isAnnotation()); System.out.println(" isAnonymous: " + clazz.isAnonymousClass()); System.out.println(" isArray: " + clazz.isArray()); System.out.println(" isEnum: " + clazz.isEnum()); System.out.println(" isInterface: " + clazz.isInterface()); System.out.println(" isLocalClass: " + clazz.isLocalClass()); System.out.println(" isMemberClass: " + clazz.isMemberClass()); System.out.println(" isPrimitive: " + clazz.isPrimitive()); System.out.println(" isSynthetic: " + clazz.isSynthetic()); System.out.println(" genericInterfaces: " + stringifyTypeArray(clazz.getGenericInterfaces())); TypeVariable<Class<?>>[] typeParameters = clazz.getTypeParameters(); System.out.println(" typeParameters: " + stringifyTypeArray(typeParameters)); } /* * Convert an array of Type into a string. Start with an array count. */ private static String stringifyTypeArray(Type[] types) { List<String> typeStringList = new ArrayList<String>(); for (Type t : types) { typeStringList.add(t.toString()); } // Sort types alphabetically so they're always printed in the same order. // For instance, Class.getClasses() does not guarantee any order for the // returned Class[]. Collections.sort(typeStringList); StringBuilder stb = new StringBuilder(); boolean first = true; stb.append("[" + types.length + "]"); for (String typeString : typeStringList) { if (first) { stb.append(" "); first = false; } else { stb.append(", "); } stb.append(typeString); } return stb.toString(); } }