// Copyright 2006 The Android Open Source Project import java.lang.reflect.*; import java.io.IOException; import java.util.Collections; /** * Reflection test. */ public class Main { void printMethodInfo(Method meth) { Class[] params, exceptions; int i; System.out.println("Method name is " + meth.getName()); System.out.println(" Declaring class is " + meth.getDeclaringClass().getName()); params = meth.getParameterTypes(); for (i = 0; i < params.length; i++) System.out.println(" Arg " + i + ": " + params[i].getName()); exceptions = meth.getExceptionTypes(); for (i = 0; i < exceptions.length; i++) System.out.println(" Exc " + i + ": " + exceptions[i].getName()); System.out.println(" Return type is " + meth.getReturnType().getName()); System.out.println(" Access flags are 0x" + Integer.toHexString(meth.getModifiers())); //System.out.println(" GenericStr is " + meth.toGenericString()); } void printFieldInfo(Field field) { System.out.println("Field name is " + field.getName()); System.out.println(" Declaring class is " + field.getDeclaringClass().getName()); System.out.println(" Field type is " + field.getType().getName()); System.out.println(" Access flags are 0x" + Integer.toHexString(field.getModifiers())); } private void showStrings(Target instance) throws NoSuchFieldException, IllegalAccessException { Class target = Target.class; String one, two, three, four; Field field = null; field = target.getField("string1"); one = (String) field.get(instance); field = target.getField("string2"); two = (String) field.get(instance); field = target.getField("string3"); three = (String) field.get(instance); System.out.println(" ::: " + one + ":" + two + ":" + three); } public void run() { Class target = Target.class; Method meth = null; Field field = null; boolean excep; try { meth = target.getMethod("myMethod", new Class[] { int.class }); if (meth.getDeclaringClass() != target) throw new RuntimeException(); printMethodInfo(meth); meth = target.getMethod("myMethod", new Class[] { float.class }); printMethodInfo(meth); meth = target.getMethod("myNoargMethod", (Class[]) null); printMethodInfo(meth); meth = target.getMethod("myMethod", new Class[] { String[].class, float.class, char.class }); printMethodInfo(meth); Target instance = new Target(); Object[] argList = new Object[] { new String[] { "hi there" }, new Float(3.1415926f), new Character('Q') }; System.out.println("Before, float is " + ((Float)argList[1]).floatValue()); Integer boxval; boxval = (Integer) meth.invoke(instance, argList); System.out.println("Result of invoke: " + boxval.intValue()); System.out.println("Calling no-arg void-return method"); meth = target.getMethod("myNoargMethod", (Class[]) null); meth.invoke(instance, (Object[]) null); /* try invoking a method that throws an exception */ meth = target.getMethod("throwingMethod", (Class[]) null); try { meth.invoke(instance, (Object[]) null); System.out.println("GLITCH: didn't throw"); } catch (InvocationTargetException ite) { System.out.println("Invoke got expected exception:"); System.out.println(ite.getClass().getName()); System.out.println(ite.getCause()); } catch (Exception ex) { System.out.println("GLITCH: invoke got wrong exception:"); ex.printStackTrace(); } System.out.println(""); field = target.getField("string1"); if (field.getDeclaringClass() != target) throw new RuntimeException(); printFieldInfo(field); String strVal = (String) field.get(instance); System.out.println(" string1 value is '" + strVal + "'"); showStrings(instance); field.set(instance, new String("a new string")); strVal = (String) field.get(instance); System.out.println(" string1 value is now '" + strVal + "'"); showStrings(instance); try { field.set(instance, new Object()); System.out.println("WARNING: able to store Object into String"); } catch (IllegalArgumentException iae) { System.out.println(" got expected illegal obj store exc"); } try { String four; field = target.getField("string4"); four = (String) field.get(instance); System.out.println("WARNING: able to access string4: " + four); } catch (IllegalAccessException iae) { System.out.println(" got expected access exc"); } catch (NoSuchFieldException nsfe) { System.out.println(" got the other expected access exc"); } try { String three; field = target.getField("string3"); three = (String) field.get(this); System.out.println("WARNING: able to get string3 in wrong obj: " + three); } catch (IllegalArgumentException iae) { System.out.println(" got expected arg exc"); } /* * Try setting a field to null. */ String four; field = target.getDeclaredField("string3"); field.set(instance, null); /* * Do some stuff with long. */ long longVal; field = target.getField("pubLong"); longVal = field.getLong(instance); System.out.println("pubLong initial value is " + Long.toHexString(longVal)); field.setLong(instance, 0x9988776655443322L); longVal = field.getLong(instance); System.out.println("pubLong new value is " + Long.toHexString(longVal)); field = target.getField("superInt"); if (field.getDeclaringClass() == target) throw new RuntimeException(); printFieldInfo(field); int intVal = field.getInt(instance); System.out.println(" superInt value is " + intVal); Integer boxedIntVal = (Integer) field.get(instance); System.out.println(" superInt boxed is " + boxedIntVal); field.set(instance, new Integer(20202)); intVal = field.getInt(instance); System.out.println(" superInt value is now " + intVal); field.setShort(instance, (short)30303); intVal = field.getInt(instance); System.out.println(" superInt value (from short) is now " +intVal); field.setInt(instance, 40404); intVal = field.getInt(instance); System.out.println(" superInt value is now " + intVal); try { field.set(instance, new Long(123)); System.out.println("FAIL: expected exception not thrown"); } catch (IllegalArgumentException iae) { System.out.println(" got expected long->int failure"); } try { field.setLong(instance, 123); System.out.println("FAIL: expected exception not thrown"); } catch (IllegalArgumentException iae) { System.out.println(" got expected long->int failure"); } try { field.set(instance, new String("abc")); System.out.println("FAIL: expected exception not thrown"); } catch (IllegalArgumentException iae) { System.out.println(" got expected string->int failure"); } try { field.getShort(instance); System.out.println("FAIL: expected exception not thrown"); } catch (IllegalArgumentException iae) { System.out.println(" got expected int->short failure"); } field = target.getField("superClassInt"); printFieldInfo(field); int superClassIntVal = field.getInt(instance); System.out.println(" superClassInt value is " + superClassIntVal); field = target.getField("staticDouble"); printFieldInfo(field); double staticDoubleVal = field.getDouble(null); System.out.println(" staticDoubleVal value is " + staticDoubleVal); try { field.getLong(instance); System.out.println("FAIL: expected exception not thrown"); } catch (IllegalArgumentException iae) { System.out.println(" got expected double->long failure"); } excep = false; try { field = target.getField("aPrivateInt"); printFieldInfo(field); } catch (NoSuchFieldException nsfe) { System.out.println("as expected: aPrivateInt not found"); excep = true; } if (!excep) System.out.println("BUG: got aPrivateInt"); field = target.getField("constantString"); printFieldInfo(field); String val = (String) field.get(instance); System.out.println(" Constant test value is " + val); field = target.getField("cantTouchThis"); printFieldInfo(field); intVal = field.getInt(instance); System.out.println(" cantTouchThis is " + intVal); try { field.setInt(instance, 99); System.out.println("ERROR: set-final succeeded\n"); } catch (IllegalAccessException iae) { System.out.println(" got expected set-final failure\n"); } intVal = field.getInt(instance); System.out.println(" cantTouchThis is now " + intVal); Constructor<Target> cons; Target targ; Object[] args; cons = target.getConstructor(new Class[] { int.class,float.class }); args = new Object[] { new Integer(7), new Float(3.3333) }; System.out.println("cons modifiers=" + cons.getModifiers()); targ = cons.newInstance(args); targ.myMethod(17); } catch (Exception ex) { System.out.println("----- unexpected exception -----"); ex.printStackTrace(); } System.out.println("ReflectTest done!"); } public static void checkType() { Method m; try { m = Collections.class.getDeclaredMethod("checkType", Object.class, Class.class); } catch (NoSuchMethodException nsme) { nsme.printStackTrace(); return; } m.setAccessible(true); try { m.invoke(null, new Object(), Object.class); } catch (IllegalAccessException iae) { iae.printStackTrace(); return; } catch (InvocationTargetException ite) { ite.printStackTrace(); return; } try { System.out.println("checkType invoking null"); m.invoke(null, new Object(), int.class); System.out.println("ERROR: should throw InvocationTargetException"); } catch (InvocationTargetException ite) { System.out.println("checkType got expected exception"); } catch (IllegalAccessException iae) { iae.printStackTrace(); return; } } public static void checkInit() { Class niuClass = NoisyInitUser.class; Method[] methods; methods = niuClass.getDeclaredMethods(); System.out.println("got methods"); /* neither NoisyInit nor NoisyInitUser should be initialized yet */ NoisyInitUser niu = new NoisyInitUser(); NoisyInit ni = new NoisyInit(); } public static void main(String[] args) { Main test = new Main(); test.run(); checkType(); checkInit(); } } class SuperTarget { public SuperTarget() { System.out.println("SuperTarget constructor ()V"); superInt = 1010101; superClassInt = 1010102; } public int myMethod(float floatArg) { System.out.println("myMethod (F)I " + floatArg); return 6; } public int superInt; public static int superClassInt; } class Target extends SuperTarget { public Target() { System.out.println("Target constructor ()V"); } public Target(int ii, float ff) { System.out.println("Target constructor (IF)V : ii=" + ii + " ff=" + ff); anInt = ii; } public int myMethod(int intarg) throws NullPointerException, IOException { System.out.println("myMethod (I)I"); System.out.println(" arg=" + intarg + " anInt=" + anInt); return 5; } public int myMethod(String[] strarg, float f, char c) { System.out.println("myMethod: " + strarg[0] + " " + f + " " + c + " !"); return 7; } public static void myNoargMethod() { System.out.println("myNoargMethod ()V"); } public void throwingMethod() { System.out.println("throwingMethod"); throw new NullPointerException("gratuitous throw!"); } public void misc() { System.out.println("misc"); } public int anInt; public String string1 = "hey"; public String string2 = "yo"; public String string3 = "there"; private String string4 = "naughty"; public static final String constantString = "a constant string"; private int aPrivateInt; public final int cantTouchThis = 77; public long pubLong = 0x1122334455667788L; public static double staticDouble = 3.3; } class NoisyInit { static { System.out.println("NoisyInit is initializing"); //Throwable th = new Throwable(); //th.printStackTrace(); } } class NoisyInitUser { static { System.out.println("NoisyInitUser is initializing"); } public void createNoisyInit(NoisyInit ni) {} }