import java.util.*; import java.util.zip.*; import java.util.List; import java.util.regex.*; import java.util.concurrent.*; import java.util.concurrent.atomic.*; import java.util.concurrent.locks.*; import javax.swing.*; import javax.swing.event.*; import javax.swing.text.*; import javax.swing.table.*; import java.io.*; import java.net.*; import java.lang.reflect.*; import java.lang.ref.*; import java.lang.management.*; import java.security.*; import java.security.spec.*; import java.awt.*; import java.awt.event.*; import java.awt.image.*; import javax.imageio.*; import java.math.*; class main { public static void main(final String[] args) throws Exception { typeWriterConsole(); gc(); long totalCommitted = 0; for (MemoryPoolMXBean b : ManagementFactory.getMemoryPoolMXBeans()) { long committed = b.getUsage().getCommitted(); print(padLeft(str(toK(committed)), 7) + "K committed: " + b.getName() + ": " + b.getUsage()); totalCommitted += committed; } print("\nTotal committed memory: " + toK(totalCommitted) + "K"); } static String str(Object o) { return o == null ? "null" : o.toString(); } static String str(char[] c) { return new String(c); } static long toK(long l) { return (l+1023)/1024; } static volatile StringBuffer local_log = new StringBuffer(); // not redirected static volatile StringBuffer print_log = local_log; // might be redirected, e.g. to main bot // in bytes - will cut to half that static volatile int print_log_max = 1024*1024; static volatile int local_log_max = 100*1024; //static int print_maxLineLength = 0; // 0 = unset static boolean print_silent; // total mute if set static Object print_byThread_lock = new Object(); static volatile ThreadLocal> print_byThread; // special handling by thread static void print() { print(""); } // slightly overblown signature to return original object... static A print(A o) { ping(); if (print_silent) return o; String s = String.valueOf(o) + "\n"; print_noNewLine(s); return o; } static void print_noNewLine(String s) { if (print_byThread != null) { F1 f = print_byThread.get(); if (f != null) if (isFalse(f.get(s))) return; } print_raw(s); } static void print_raw(String s) { s = fixNewLines(s); // TODO if (print_maxLineLength != 0) StringBuffer loc = local_log; StringBuffer buf = print_log; int loc_max = print_log_max; if (buf != loc && buf != null) { print_append(buf, s, print_log_max); loc_max = local_log_max; } if (loc != null) print_append(loc, s, loc_max); System.out.print(s); } static void print(long l) { print(String.valueOf(l)); } static void print(char c) { print(String.valueOf(c)); } static void print_append(StringBuffer buf, String s, int max) { synchronized(buf) { buf.append(s); max /= 2; if (buf.length() > max) try { int newLength = max/2; int ofs = buf.length()-newLength; String newString = buf.substring(ofs); buf.setLength(0); buf.append("[...] ").append(newString); } catch (Exception e) { buf.setLength(0); } } } static Map _registerThread_threads = Collections.synchronizedMap(new WeakHashMap()); static Thread _registerThread(Thread t) { _registerThread_threads.put(t, true); return t; } static void _registerThread() { _registerThread(Thread.currentThread()); } static void gc() { System.gc(); } static String padLeft(String s, char c, int n) { return rep(c, n-l(s)) + s; } // default to space static String padLeft(String s, int n) { return padLeft(s, ' ', n); } static String fixNewLines(String s) { return s.replace("\r\n", "\n").replace("\r", "\n"); } static volatile boolean ping_pauseAll; static int ping_sleep = 100; // poll pauseAll flag every 100 static volatile boolean ping_anyActions; static Map ping_actions = synchroMap(new WeakHashMap()); // always returns true static boolean ping() { if (ping_pauseAll || ping_anyActions) ping_impl(); return true; } // returns true when it slept static boolean ping_impl() { try { if (ping_pauseAll && !isAWTThread()) { do Thread.sleep(ping_sleep); while (ping_pauseAll); return true; } if (ping_anyActions) { Object action; synchronized(ping_actions) { action = ping_actions.get(currentThread()); if (action instanceof Runnable) ping_actions.remove(currentThread()); if (ping_actions.isEmpty()) ping_anyActions = false; } if (action instanceof Runnable) ((Runnable) action).run(); else if (eq(action, "cancelled")) throw fail("Thread cancelled."); } return false; } catch (Exception __e) { throw rethrow(__e); } } static boolean isFalse(Object o) { return eq(false, o); } static String rep(int n, char c) { return repeat(c, n); } static String rep(char c, int n) { return repeat(c, n); } static List rep(A a, int n) { return repeat(a, n); } static List rep(int n, A a) { return repeat(n, a); } static int l(Object[] a) { return a == null ? 0 : a.length; } static int l(boolean[] a) { return a == null ? 0 : a.length; } static int l(byte[] a) { return a == null ? 0 : a.length; } static int l(int[] a) { return a == null ? 0 : a.length; } static int l(float[] a) { return a == null ? 0 : a.length; } static int l(char[] a) { return a == null ? 0 : a.length; } static int l(Collection c) { return c == null ? 0 : c.size(); } static int l(Map m) { return m == null ? 0 : m.size(); } static int l(CharSequence s) { return s == null ? 0 : s.length(); } static long l(File f) { return f == null ? 0 : f.length(); } static int l(Object o) { return o instanceof String ? l((String) o) : o instanceof Map ? l((Map) o) : l((Collection) o); // incomplete } static Map synchroMap() { return synchroHashMap(); } static Map synchroMap(Map map) { return Collections.synchronizedMap(map); } static Thread currentThread() { return Thread.currentThread(); } static boolean eq(Object a, Object b) { return a == null ? b == null : a == b || a.equals(b); } static RuntimeException fail() { throw new RuntimeException("fail"); } static RuntimeException fail(Throwable e) { throw asRuntimeException(e); } static RuntimeException fail(Object msg) { throw new RuntimeException(String.valueOf(msg)); } static RuntimeException fail(String msg) { throw new RuntimeException(unnull(msg)); } static RuntimeException fail(String msg, Throwable innerException) { throw new RuntimeException(msg, innerException); } static String repeat(char c, int n) { n = Math.max(n, 0); char[] chars = new char[n]; for (int i = 0; i < n; i++) chars[i] = c; return new String(chars); } static List repeat(A a, int n) { List l = new ArrayList(n); for (int i = 0; i < n; i++) l.add(a); return l; } static List repeat(int n, A a) { return repeat(a, n); } // TODO: test if android complains about this static boolean isAWTThread() { if (isAndroid()) return false; if (isHeadless()) return false; return isAWTThread_awt(); } static boolean isAWTThread_awt() { return SwingUtilities.isEventDispatchThread(); } static Boolean isHeadless_cache; static boolean isHeadless() { if (isHeadless_cache != null) return isHeadless_cache; if (GraphicsEnvironment.isHeadless()) return isHeadless_cache = true; // Also check if AWT actually works. // If DISPLAY variable is set but no X server up, this will notice. try { SwingUtilities.isEventDispatchThread(); return isHeadless_cache = false; } catch (Throwable e) { return isHeadless_cache = true; } } static String unnull(String s) { return s == null ? "" : s; } static List unnull(List l) { return l == null ? emptyList() : l; } static Iterable unnull(Iterable i) { return i == null ? emptyList() : i; } static Object[] unnull(Object[] a) { return a == null ? new Object[0] : a; } static BitSet unnull(BitSet b) { return b == null ? new BitSet() : b; } static RuntimeException asRuntimeException(Throwable t) { return t instanceof RuntimeException ? (RuntimeException) t : new RuntimeException(t); } static Map synchroHashMap() { return Collections.synchronizedMap(new HashMap()); } static int isAndroid_flag; static boolean isAndroid() { if (isAndroid_flag == 0) isAndroid_flag = System.getProperty("java.vendor").toLowerCase().indexOf("android") >= 0 ? 1 : -1; return isAndroid_flag > 0; } static List emptyList() { return new ArrayList(); //ret Collections.emptyList(); } static abstract class F1 { abstract B get(A a); } // get purpose 1: access a list/array/map (safer version of x.get(y)) static A get(List l, int idx) { return l != null && idx >= 0 && idx < l(l) ? l.get(idx) : null; } // seems to conflict with other signatures /*static B get(Map map, A key) { ret map != null ? map.get(key) : null; }*/ static A get(A[] l, int idx) { return idx >= 0 && idx < l(l) ? l[idx] : null; } // default to false static boolean get(boolean[] l, int idx) { return idx >= 0 && idx < l(l) ? l[idx] : false; } // get purpose 2: access a field by reflection or a map static Object get(Object o, String field) { try { if (o instanceof Class) return get((Class) o, field); if (o instanceof Map) return ((Map) o).get(field); Field f = getOpt_findField(o.getClass(), field); if (f != null) { f.setAccessible(true); return f.get(o); } } catch (Exception e) { throw asRuntimeException(e); } throw new RuntimeException("Field '" + field + "' not found in " + o.getClass().getName()); } static Object get_raw(Object o, String field) { try { Field f = get_findField(o.getClass(), field); f.setAccessible(true); return f.get(o); } catch (Exception e) { throw new RuntimeException(e); } } static Object get(Class c, String field) { try { Field f = get_findStaticField(c, field); f.setAccessible(true); return f.get(null); } catch (Exception e) { throw new RuntimeException(e); } } static Field get_findStaticField(Class c, String field) { Class _c = c; do { for (Field f : _c.getDeclaredFields()) if (f.getName().equals(field) && (f.getModifiers() & Modifier.STATIC) != 0) return f; _c = _c.getSuperclass(); } while (_c != null); throw new RuntimeException("Static field '" + field + "' not found in " + c.getName()); } static Field get_findField(Class c, String field) { Class _c = c; do { for (Field f : _c.getDeclaredFields()) if (f.getName().equals(field)) return f; _c = _c.getSuperclass(); } while (_c != null); throw new RuntimeException("Field '" + field + "' not found in " + c.getName()); } static void typeWriterConsole() { if (isHeadless()) return; Font f = typeWriterFont(); consoleFont(f); consoleInputFont(f); } static RuntimeException rethrow(Throwable e) { throw asRuntimeException(e); } static Font typeWriterFont() { return typeWriterFont(14); } static Font typeWriterFont(int size) { return new Font("Courier", Font.PLAIN, size); } static void consoleFont(Font font) { callOpt(getConsoleTextArea_gen(), "setFont", font); } static Field getOpt_findField(Class c, String field) { Class _c = c; do { for (Field f : _c.getDeclaredFields()) if (f.getName().equals(field)) return f; _c = _c.getSuperclass(); } while (_c != null); return null; } static void consoleInputFont(final Font f) { { swingAndWait(new Runnable() { public void run() { try { JTextField input = consoleInputField(); if (input != null) { input.setFont(f); revalidateFrame(input); } } catch (Exception __e) { throw rethrow(__e); } } public String toString() { return "JTextField input = consoleInputField();\r\n if (input != null) {\r\n input.s..."; }}); } } static Object callOpt(Object o) { if (o == null) return null; return callF(o); } static Object callOpt(Object o, String method, Object... args) { try { if (o == null) return null; if (o instanceof Class) { Method m = callOpt_findStaticMethod((Class) o, method, args, false); if (m == null) return null; m.setAccessible(true); return m.invoke(null, args); } else { Method m = callOpt_findMethod(o, method, args, false); if (m == null) return null; m.setAccessible(true); return m.invoke(o, args); } } catch (Exception e) { //fail(e.getMessage() + " | Method: " + method + ", receiver: " + className(o) + ", args: (" + join(", ", map(f className, args) + ")"); throw new RuntimeException(e); } } static Method callOpt_findStaticMethod(Class c, String method, Object[] args, boolean debug) { Class _c = c; while (c != null) { for (Method m : c.getDeclaredMethods()) { if (debug) System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");; if (!m.getName().equals(method)) { if (debug) System.out.println("Method name mismatch: " + method); continue; } if ((m.getModifiers() & Modifier.STATIC) == 0 || !callOpt_checkArgs(m, args, debug)) continue; return m; } c = c.getSuperclass(); } return null; } static Method callOpt_findMethod(Object o, String method, Object[] args, boolean debug) { Class c = o.getClass(); while (c != null) { for (Method m : c.getDeclaredMethods()) { if (debug) System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");; if (m.getName().equals(method) && callOpt_checkArgs(m, args, debug)) return m; } c = c.getSuperclass(); } return null; } private static boolean callOpt_checkArgs(Method m, Object[] args, boolean debug) { Class[] types = m.getParameterTypes(); if (types.length != args.length) { if (debug) System.out.println("Bad parameter length: " + args.length + " vs " + types.length); return false; } for (int i = 0; i < types.length; i++) if (!(args[i] == null || isInstanceX(types[i], args[i]))) { if (debug) System.out.println("Bad parameter " + i + ": " + args[i] + " vs " + types[i]); return false; } return true; } static void revalidateFrame(Component c) { revalidate(getFrame(c)); } static Object getConsoleTextArea_gen() { return getOpt(get(getJavaX(), "console"), "textArea"); } static JTextField consoleInputField() { return (JTextField) getOpt(get(getJavaX(), "console"), "tfInput"); } static JFrame getFrame(final Object _o) { return swing(new F0() { JFrame get() { try { Object o = _o; if (o instanceof ButtonGroup) o = first(buttonsInGroup((ButtonGroup) o)); if (!(o instanceof Component)) return null; Component c = (Component) o; while (c != null) { if (c instanceof JFrame) return (JFrame) c; c = c.getParent(); } return null; } catch (Exception __e) { throw rethrow(__e); } } public String toString() { return "O o = _o;\r\n if (o instanceof ButtonGroup) o = first(buttonsInGroup((ButtonGro..."; }}); } static WeakHashMap> callF_cache = new WeakHashMap(); static Object callF(Object f, Object... args) { try { if (f instanceof String) return callMC((String) f, args); if (f instanceof Runnable) { ((Runnable) f).run(); return null; } if (f == null) return null; Class c = f.getClass(); ArrayList methods; synchronized(callF_cache) { methods = callF_cache.get(c); if (methods == null) methods = callF_makeCache(c); } int n = l(methods); if (n == 0) throw fail("No get method in " + getClassName(c)); if (n == 1) return methods.get(0).invoke(f, args); for (int i = 0; i < n; i++) { Method m = methods.get(i); if (call_checkArgs(m, args, false)) return m.invoke(f, args); } throw fail("No matching get method in " + getClassName(c)); } catch (Exception __e) { throw rethrow(__e); } } // used internally static ArrayList callF_makeCache(Class c) { ArrayList l = new ArrayList(); Class _c = c; do { for (Method m : _c.getDeclaredMethods()) if (m.getName().equals("get")) { m.setAccessible(true); l.add(m); } if (!l.isEmpty()) break; _c = _c.getSuperclass(); } while (_c != null); callF_cache.put(c, l); return l; } // extended over Class.isInstance() to handle primitive types static boolean isInstanceX(Class type, Object arg) { if (type == boolean.class) return arg instanceof Boolean; if (type == int.class) return arg instanceof Integer; if (type == long.class) return arg instanceof Long; if (type == float.class) return arg instanceof Float; if (type == short.class) return arg instanceof Short; if (type == char.class) return arg instanceof Character; if (type == byte.class) return arg instanceof Byte; if (type == double.class) return arg instanceof Double; return type.isInstance(arg); } static Class __javax; static Class getJavaX() { return __javax; } static void revalidate(final Component c) { if (c == null || !c.isShowing()) return; { swingAndWait(new Runnable() { public void run() { try { // magic combo to actually relayout and repaint c.revalidate(); c.repaint(); } catch (Exception __e) { throw rethrow(__e); } } public String toString() { return "// magic combo to actually relayout and repaint\r\n c.revalidate();\r\n c.repa..."; }}); } } static Object getOpt(Object o, String field) { return getOpt_cached(o, field); } static Object getOpt_raw(Object o, String field) { try { Field f = getOpt_findField(o.getClass(), field); if (f == null) return null; f.setAccessible(true); return f.get(o); } catch (Exception e) { throw new RuntimeException(e); } } static Object getOpt(Class c, String field) { try { if (c == null) return null; Field f = getOpt_findStaticField(c, field); if (f == null) return null; f.setAccessible(true); return f.get(null); } catch (Exception e) { throw new RuntimeException(e); } } static Field getOpt_findStaticField(Class c, String field) { Class _c = c; do { for (Field f : _c.getDeclaredFields()) if (f.getName().equals(field) && (f.getModifiers() & Modifier.STATIC) != 0) return f; _c = _c.getSuperclass(); } while (_c != null); return null; } static final HashMap> callMC_cache = new HashMap(); static String callMC_key; static Method callMC_value; // varargs assignment fixer for a single string array argument static Object callMC(String method, String[] arg) { return callMC(method, new Object[] {arg}); } static Object callMC(String method, Object... args) { try { Method me; synchronized(callMC_cache) { me = method == callMC_key ? callMC_value : null; } if (me != null) return callMC_value.invoke(null, args); List m; synchronized(callMC_cache) { m = callMC_cache.get(method); } if (m == null) { if (callMC_cache.isEmpty()) { callMC_makeCache(); m = callMC_cache.get(method); } if (m == null) throw fail("Method named " + method + " not found in main"); } int n = m.size(); if (n == 1) { me = m.get(0); synchronized(callMC_cache) { callMC_key = method; callMC_value = me; } return me.invoke(null, args); } for (int i = 0; i < n; i++) { me = m.get(i); if (call_checkArgs(me, args, false)) return me.invoke(null, args); } throw fail("No method called " + method + " with matching arguments found in main"); } catch (Exception __e) { throw rethrow(__e); } } static void callMC_makeCache() { synchronized(callMC_cache) { callMC_cache.clear(); Class _c = (Class) mc(), c = _c; while (c != null) { for (Method m : c.getDeclaredMethods()) if ((m.getModifiers() & Modifier.STATIC) != 0) { m.setAccessible(true); multiMapPut(callMC_cache, m.getName(), m); } c = c.getSuperclass(); } } } static Object call(Object o) { return callFunction(o); } // varargs assignment fixer for a single string array argument static Object call(Object o, String method, String[] arg) { return call(o, method, new Object[] {arg}); } static Object call(Object o, String method, Object... args) { try { if (o instanceof Class) { Method m = call_findStaticMethod((Class) o, method, args, false); m.setAccessible(true); return m.invoke(null, args); } else { Method m = call_findMethod(o, method, args, false); m.setAccessible(true); return m.invoke(o, args); } } catch (Exception e) { throw e instanceof RuntimeException ? (RuntimeException) e : new RuntimeException(e); } } static Method call_findStaticMethod(Class c, String method, Object[] args, boolean debug) { Class _c = c; while (c != null) { for (Method m : c.getDeclaredMethods()) { if (debug) System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");; if (!m.getName().equals(method)) { if (debug) System.out.println("Method name mismatch: " + method); continue; } if ((m.getModifiers() & Modifier.STATIC) == 0 || !call_checkArgs(m, args, debug)) continue; return m; } c = c.getSuperclass(); } throw new RuntimeException("Method '" + method + "' (static) with " + args.length + " parameter(s) not found in " + _c.getName()); } static Method call_findMethod(Object o, String method, Object[] args, boolean debug) { Class c = o.getClass(); while (c != null) { for (Method m : c.getDeclaredMethods()) { if (debug) System.out.println("Checking method " + m.getName() + " with " + m.getParameterTypes().length + " parameters");; if (m.getName().equals(method) && call_checkArgs(m, args, debug)) return m; } c = c.getSuperclass(); } throw new RuntimeException("Method '" + method + "' (non-static) with " + args.length + " parameter(s) not found in " + o.getClass().getName()); } private static boolean call_checkArgs(Method m, Object[] args, boolean debug) { Class[] types = m.getParameterTypes(); if (types.length != args.length) { if (debug) System.out.println("Bad parameter length: " + args.length + " vs " + types.length); return false; } for (int i = 0; i < types.length; i++) if (!(args[i] == null || isInstanceX(types[i], args[i]))) { if (debug) System.out.println("Bad parameter " + i + ": " + args[i] + " vs " + types[i]); return false; } return true; } static String getClassName(Object o) { return o == null ? "null" : o.getClass().getName(); } static List buttonsInGroup(ButtonGroup g) { if (g == null) return ll(); return asList(g.getElements()); } static final WeakHashMap> getOpt_cache = new WeakHashMap(); static final HashMap getOpt_special = new HashMap(); // just a marker static { getOpt_cache.put(Class.class, getOpt_special); getOpt_cache.put(String.class, getOpt_special); } static Object getOpt_cached(Object o, String field) { try { if (o == null) return null; Class c = o.getClass(); HashMap map; synchronized(getOpt_cache) { map = getOpt_cache.get(c); if (map == null) map = getOpt_makeCache(c); } if (map == getOpt_special) { if (o instanceof Class) return getOpt((Class) o, field); /*if (o instanceof S) ret getOpt(getBot((S) o), field);*/ if (o instanceof Map) return ((Map) o).get(field); } Field f = map.get(field); if (f != null) return f.get(o); return null; } catch (Exception __e) { throw rethrow(__e); } } // used internally - we are in synchronized block static HashMap getOpt_makeCache(Class c) { HashMap map; if (isSubtypeOf(c, Map.class)) map = getOpt_special; else { map = new HashMap(); Class _c = c; do { for (Field f : _c.getDeclaredFields()) { f.setAccessible(true); String name = f.getName(); if (!map.containsKey(name)) map.put(name, f); } _c = _c.getSuperclass(); } while (_c != null); } getOpt_cache.put(c, map); return map; } static Object swing(Object f) { return swingAndWait(f); } static A swing(F0 f) { return (A) swingAndWait(f); } static Object first(Object list) { return empty((List) list) ? null : ((List) list).get(0); } static A first(List list) { return empty(list) ? null : list.get(0); } static A first(A[] bla) { return bla == null || bla.length == 0 ? null : bla[0]; } static A first(Iterable i) { if (i == null) return null; Iterator it = i.iterator(); return it.hasNext() ? it.next() : null; } static Character first(String s) { return empty(s) ? null : s.charAt(0); } static List ll(A... a) { return litlist(a); } static Object callFunction(Object f, Object... args) { return callF(f, args); } static ArrayList asList(A[] a) { return new ArrayList(Arrays.asList(a)); } static ArrayList asList(int[] a) { ArrayList l = new ArrayList(); for (int i : a) l.add(i); return l; } static ArrayList asList(Iterable s) { if (s instanceof ArrayList) return (ArrayList) s; ArrayList l = new ArrayList(); if (s != null) for (A a : s) l.add(a); return l; } static ArrayList asList(Enumeration e) { ArrayList l = new ArrayList(); if (e != null) while (e.hasMoreElements()) l.add(e.nextElement()); return l; } static boolean empty(Collection c) { return c == null || c.isEmpty(); } static boolean empty(String s) { return s == null || s.length() == 0; } static boolean empty(Map map) { return map == null || map.isEmpty(); } static boolean empty(Object[] o) { return o == null || o.length == 0; } static boolean empty(Object o) { if (o instanceof Collection) return empty((Collection) o); if (o instanceof String) return empty((String) o); if (o instanceof Map) return empty((Map) o); if (o instanceof Object[]) return empty((Object[]) o); throw fail("unknown type for 'empty': " + getType(o)); } static boolean empty(float[] a) { return a == null || a.length == 0; } static boolean empty(int[] a) { return a == null || a.length == 0; } static boolean empty(long[] a) { return a == null || a.length == 0; } static Class mc() { return main.class; } static void multiMapPut(Map> map, A a, B b) { List l = map.get(a); if (l == null) map.put(a, l = new ArrayList()); l.add(b); } static void swingAndWait(Runnable r) { try { if (isAWTThread()) r.run(); else EventQueue.invokeAndWait(r); } catch (Exception __e) { throw rethrow(__e); } } static Object swingAndWait(final Object f) { if (isAWTThread()) return callF(f); else { final Var result = new Var(); swingAndWait(new Runnable() { public void run() { try { result.set(callF(f)); } catch (Exception __e) { throw rethrow(__e); } } public String toString() { return "result.set(callF(f));"; }}); return result.get(); } } static boolean isSubtypeOf(Class a, Class b) { return b.isAssignableFrom(a); // << always hated that method, let's replace it! } static String getType(Object o) { return getClassName(o); } static ArrayList litlist(A... a) { return new ArrayList(Arrays.asList(a)); } static abstract class F0 { abstract A get(); } static class Var implements IVar { A v; // you can access this directly if you use one thread Var() {} Var(A v) { this.v = v;} public synchronized void set(A a) { if (v != a) { v = a; notifyAll(); } } public synchronized A get() { return v; } public synchronized boolean has() { return v != null; } public synchronized void clear() { v = null; } } static interface IVar { void set(A a); A get(); boolean has(); void clear(); } }