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26 package java.lang.reflect;
28 import java.lang.annotation.Annotation;
29 import org.apidesign.bck2brwsr.core.JavaScriptBody;
30 import org.apidesign.bck2brwsr.emul.AnnotationImpl;
31 import org.apidesign.bck2brwsr.emul.MethodImpl;
34 * A {@code Method} provides information about, and access to, a single method
35 * on a class or interface. The reflected method may be a class method
36 * or an instance method (including an abstract method).
38 * <p>A {@code Method} permits widening conversions to occur when matching the
39 * actual parameters to invoke with the underlying method's formal
40 * parameters, but it throws an {@code IllegalArgumentException} if a
41 * narrowing conversion would occur.
44 * @see java.lang.Class
45 * @see java.lang.Class#getMethods()
46 * @see java.lang.Class#getMethod(String, Class[])
47 * @see java.lang.Class#getDeclaredMethods()
48 * @see java.lang.Class#getDeclaredMethod(String, Class[])
50 * @author Kenneth Russell
51 * @author Nakul Saraiya
54 class Method extends AccessibleObject implements GenericDeclaration,
56 private final Class<?> clazz;
57 private final String name;
58 private final Object data;
59 private final String sig;
60 private int modifiers;
62 // Generics infrastructure
64 private String getGenericSignature() {return null;}
67 * Package-private constructor used by ReflectAccess to enable
68 * instantiation of these objects in Java code from the java.lang
69 * package via sun.reflect.LangReflectAccess.
71 Method(Class<?> declaringClass, String name, Object data, String sig)
73 this.clazz = declaringClass;
80 * Package-private routine (exposed to java.lang.Class via
81 * ReflectAccess) which returns a copy of this Method. The copy's
82 * "root" field points to this Method.
89 * Returns the {@code Class} object representing the class or interface
90 * that declares the method represented by this {@code Method} object.
92 public Class<?> getDeclaringClass() {
97 * Returns the name of the method represented by this {@code Method}
98 * object, as a {@code String}.
100 public String getName() {
105 * Returns the Java language modifiers for the method represented
106 * by this {@code Method} object, as an integer. The {@code Modifier} class should
107 * be used to decode the modifiers.
111 public int getModifiers() {
116 * Returns an array of {@code TypeVariable} objects that represent the
117 * type variables declared by the generic declaration represented by this
118 * {@code GenericDeclaration} object, in declaration order. Returns an
119 * array of length 0 if the underlying generic declaration declares no type
122 * @return an array of {@code TypeVariable} objects that represent
123 * the type variables declared by this generic declaration
124 * @throws GenericSignatureFormatError if the generic
125 * signature of this generic declaration does not conform to
126 * the format specified in
127 * <cite>The Java™ Virtual Machine Specification</cite>
130 public TypeVariable<Method>[] getTypeParameters() {
131 throw new UnsupportedOperationException();
135 * Returns a {@code Class} object that represents the formal return type
136 * of the method represented by this {@code Method} object.
138 * @return the return type for the method this object represents
140 public Class<?> getReturnType() {
141 switch (sig.charAt(0)) {
142 case 'I': return Integer.TYPE;
143 case 'J': return Long.TYPE;
144 case 'D': return Double.TYPE;
145 case 'F': return Float.TYPE;
146 case 'B': return Byte.TYPE;
147 case 'Z': return Boolean.TYPE;
148 case 'S': return Short.TYPE;
149 // case 'V': return Void.TYPE;
151 int up = sig.indexOf("_2");
152 String type = sig.substring(1, up);
153 return Class.forName(type);
154 } catch (ClassNotFoundException ex) {
158 throw new UnsupportedOperationException(sig);
162 * Returns a {@code Type} object that represents the formal return
163 * type of the method represented by this {@code Method} object.
165 * <p>If the return type is a parameterized type,
166 * the {@code Type} object returned must accurately reflect
167 * the actual type parameters used in the source code.
169 * <p>If the return type is a type variable or a parameterized type, it
170 * is created. Otherwise, it is resolved.
172 * @return a {@code Type} object that represents the formal return
173 * type of the underlying method
174 * @throws GenericSignatureFormatError
175 * if the generic method signature does not conform to the format
177 * <cite>The Java™ Virtual Machine Specification</cite>
178 * @throws TypeNotPresentException if the underlying method's
179 * return type refers to a non-existent type declaration
180 * @throws MalformedParameterizedTypeException if the
181 * underlying method's return typed refers to a parameterized
182 * type that cannot be instantiated for any reason
185 public Type getGenericReturnType() {
186 throw new UnsupportedOperationException();
191 * Returns an array of {@code Class} objects that represent the formal
192 * parameter types, in declaration order, of the method
193 * represented by this {@code Method} object. Returns an array of length
194 * 0 if the underlying method takes no parameters.
196 * @return the parameter types for the method this object
199 public Class<?>[] getParameterTypes() {
200 throw new UnsupportedOperationException();
201 //return (Class<?>[]) parameterTypes.clone();
205 * Returns an array of {@code Type} objects that represent the formal
206 * parameter types, in declaration order, of the method represented by
207 * this {@code Method} object. Returns an array of length 0 if the
208 * underlying method takes no parameters.
210 * <p>If a formal parameter type is a parameterized type,
211 * the {@code Type} object returned for it must accurately reflect
212 * the actual type parameters used in the source code.
214 * <p>If a formal parameter type is a type variable or a parameterized
215 * type, it is created. Otherwise, it is resolved.
217 * @return an array of Types that represent the formal
218 * parameter types of the underlying method, in declaration order
219 * @throws GenericSignatureFormatError
220 * if the generic method signature does not conform to the format
222 * <cite>The Java™ Virtual Machine Specification</cite>
223 * @throws TypeNotPresentException if any of the parameter
224 * types of the underlying method refers to a non-existent type
226 * @throws MalformedParameterizedTypeException if any of
227 * the underlying method's parameter types refer to a parameterized
228 * type that cannot be instantiated for any reason
231 public Type[] getGenericParameterTypes() {
232 throw new UnsupportedOperationException();
237 * Returns an array of {@code Class} objects that represent
238 * the types of the exceptions declared to be thrown
239 * by the underlying method
240 * represented by this {@code Method} object. Returns an array of length
241 * 0 if the method declares no exceptions in its {@code throws} clause.
243 * @return the exception types declared as being thrown by the
244 * method this object represents
246 public Class<?>[] getExceptionTypes() {
247 throw new UnsupportedOperationException();
248 //return (Class<?>[]) exceptionTypes.clone();
252 * Returns an array of {@code Type} objects that represent the
253 * exceptions declared to be thrown by this {@code Method} object.
254 * Returns an array of length 0 if the underlying method declares
255 * no exceptions in its {@code throws} clause.
257 * <p>If an exception type is a type variable or a parameterized
258 * type, it is created. Otherwise, it is resolved.
260 * @return an array of Types that represent the exception types
261 * thrown by the underlying method
262 * @throws GenericSignatureFormatError
263 * if the generic method signature does not conform to the format
265 * <cite>The Java™ Virtual Machine Specification</cite>
266 * @throws TypeNotPresentException if the underlying method's
267 * {@code throws} clause refers to a non-existent type declaration
268 * @throws MalformedParameterizedTypeException if
269 * the underlying method's {@code throws} clause refers to a
270 * parameterized type that cannot be instantiated for any reason
273 public Type[] getGenericExceptionTypes() {
274 throw new UnsupportedOperationException();
278 * Compares this {@code Method} against the specified object. Returns
279 * true if the objects are the same. Two {@code Methods} are the same if
280 * they were declared by the same class and have the same name
281 * and formal parameter types and return type.
283 public boolean equals(Object obj) {
284 if (obj != null && obj instanceof Method) {
285 Method other = (Method)obj;
286 return data == other.data;
292 * Returns a hashcode for this {@code Method}. The hashcode is computed
293 * as the exclusive-or of the hashcodes for the underlying
294 * method's declaring class name and the method's name.
296 public int hashCode() {
297 return getDeclaringClass().getName().hashCode() ^ getName().hashCode();
301 * Returns a string describing this {@code Method}. The string is
302 * formatted as the method access modifiers, if any, followed by
303 * the method return type, followed by a space, followed by the
304 * class declaring the method, followed by a period, followed by
305 * the method name, followed by a parenthesized, comma-separated
306 * list of the method's formal parameter types. If the method
307 * throws checked exceptions, the parameter list is followed by a
308 * space, followed by the word throws followed by a
309 * comma-separated list of the thrown exception types.
312 * public boolean java.lang.Object.equals(java.lang.Object)
315 * <p>The access modifiers are placed in canonical order as
316 * specified by "The Java Language Specification". This is
317 * {@code public}, {@code protected} or {@code private} first,
318 * and then other modifiers in the following order:
319 * {@code abstract}, {@code static}, {@code final},
320 * {@code synchronized}, {@code native}, {@code strictfp}.
322 public String toString() {
324 StringBuilder sb = new StringBuilder();
325 int mod = getModifiers() & Modifier.methodModifiers();
327 sb.append(Modifier.toString(mod)).append(' ');
329 sb.append(Field.getTypeName(getReturnType())).append(' ');
330 sb.append(Field.getTypeName(getDeclaringClass())).append('.');
331 sb.append(getName()).append('(');
333 Class<?>[] params = parameterTypes; // avoid clone
334 for (int j = 0; j < params.length; j++) {
335 sb.append(Field.getTypeName(params[j]));
336 if (j < (params.length - 1))
340 Class<?>[] exceptions = exceptionTypes; // avoid clone
341 if (exceptions.length > 0) {
342 sb.append(" throws ");
343 for (int k = 0; k < exceptions.length; k++) {
344 sb.append(exceptions[k].getName());
345 if (k < (exceptions.length - 1))
350 return sb.toString();
351 } catch (Exception e) {
352 return "<" + e + ">";
357 * Returns a string describing this {@code Method}, including
358 * type parameters. The string is formatted as the method access
359 * modifiers, if any, followed by an angle-bracketed
360 * comma-separated list of the method's type parameters, if any,
361 * followed by the method's generic return type, followed by a
362 * space, followed by the class declaring the method, followed by
363 * a period, followed by the method name, followed by a
364 * parenthesized, comma-separated list of the method's generic
365 * formal parameter types.
367 * If this method was declared to take a variable number of
368 * arguments, instead of denoting the last parameter as
369 * "<tt><i>Type</i>[]</tt>", it is denoted as
370 * "<tt><i>Type</i>...</tt>".
372 * A space is used to separate access modifiers from one another
373 * and from the type parameters or return type. If there are no
374 * type parameters, the type parameter list is elided; if the type
375 * parameter list is present, a space separates the list from the
376 * class name. If the method is declared to throw exceptions, the
377 * parameter list is followed by a space, followed by the word
378 * throws followed by a comma-separated list of the generic thrown
379 * exception types. If there are no type parameters, the type
380 * parameter list is elided.
382 * <p>The access modifiers are placed in canonical order as
383 * specified by "The Java Language Specification". This is
384 * {@code public}, {@code protected} or {@code private} first,
385 * and then other modifiers in the following order:
386 * {@code abstract}, {@code static}, {@code final},
387 * {@code synchronized}, {@code native}, {@code strictfp}.
389 * @return a string describing this {@code Method},
390 * include type parameters
394 public String toGenericString() {
396 StringBuilder sb = new StringBuilder();
397 int mod = getModifiers() & Modifier.methodModifiers();
399 sb.append(Modifier.toString(mod)).append(' ');
401 TypeVariable<?>[] typeparms = getTypeParameters();
402 if (typeparms.length > 0) {
403 boolean first = true;
405 for(TypeVariable<?> typeparm: typeparms) {
408 // Class objects can't occur here; no need to test
409 // and call Class.getName().
410 sb.append(typeparm.toString());
416 Type genRetType = getGenericReturnType();
417 sb.append( ((genRetType instanceof Class<?>)?
418 Field.getTypeName((Class<?>)genRetType):genRetType.toString()))
421 sb.append(Field.getTypeName(getDeclaringClass())).append('.');
422 sb.append(getName()).append('(');
423 Type[] params = getGenericParameterTypes();
424 for (int j = 0; j < params.length; j++) {
425 String param = (params[j] instanceof Class)?
426 Field.getTypeName((Class)params[j]):
427 (params[j].toString());
428 if (isVarArgs() && (j == params.length - 1)) // replace T[] with T...
429 param = param.replaceFirst("\\[\\]$", "...");
431 if (j < (params.length - 1))
435 Type[] exceptions = getGenericExceptionTypes();
436 if (exceptions.length > 0) {
437 sb.append(" throws ");
438 for (int k = 0; k < exceptions.length; k++) {
439 sb.append((exceptions[k] instanceof Class)?
440 ((Class)exceptions[k]).getName():
441 exceptions[k].toString());
442 if (k < (exceptions.length - 1))
446 return sb.toString();
447 } catch (Exception e) {
448 return "<" + e + ">";
453 * Invokes the underlying method represented by this {@code Method}
454 * object, on the specified object with the specified parameters.
455 * Individual parameters are automatically unwrapped to match
456 * primitive formal parameters, and both primitive and reference
457 * parameters are subject to method invocation conversions as
460 * <p>If the underlying method is static, then the specified {@code obj}
461 * argument is ignored. It may be null.
463 * <p>If the number of formal parameters required by the underlying method is
464 * 0, the supplied {@code args} array may be of length 0 or null.
466 * <p>If the underlying method is an instance method, it is invoked
467 * using dynamic method lookup as documented in The Java Language
468 * Specification, Second Edition, section 15.12.4.4; in particular,
469 * overriding based on the runtime type of the target object will occur.
471 * <p>If the underlying method is static, the class that declared
472 * the method is initialized if it has not already been initialized.
474 * <p>If the method completes normally, the value it returns is
475 * returned to the caller of invoke; if the value has a primitive
476 * type, it is first appropriately wrapped in an object. However,
477 * if the value has the type of an array of a primitive type, the
478 * elements of the array are <i>not</i> wrapped in objects; in
479 * other words, an array of primitive type is returned. If the
480 * underlying method return type is void, the invocation returns
483 * @param obj the object the underlying method is invoked from
484 * @param args the arguments used for the method call
485 * @return the result of dispatching the method represented by
486 * this object on {@code obj} with parameters
489 * @exception IllegalAccessException if this {@code Method} object
490 * is enforcing Java language access control and the underlying
491 * method is inaccessible.
492 * @exception IllegalArgumentException if the method is an
493 * instance method and the specified object argument
494 * is not an instance of the class or interface
495 * declaring the underlying method (or of a subclass
496 * or implementor thereof); if the number of actual
497 * and formal parameters differ; if an unwrapping
498 * conversion for primitive arguments fails; or if,
499 * after possible unwrapping, a parameter value
500 * cannot be converted to the corresponding formal
501 * parameter type by a method invocation conversion.
502 * @exception InvocationTargetException if the underlying method
503 * throws an exception.
504 * @exception NullPointerException if the specified object is null
505 * and the method is an instance method.
506 * @exception ExceptionInInitializerError if the initialization
507 * provoked by this method fails.
509 public Object invoke(Object obj, Object... args)
510 throws IllegalAccessException, IllegalArgumentException,
511 InvocationTargetException
513 Object res = invoke0(this, obj, args);
514 if (getReturnType().isPrimitive()) {
515 res = fromPrimitive(getReturnType(), res);
520 @JavaScriptBody(args = { "method", "self", "args" }, body =
521 "if (args.length > 0) throw 'unsupported now';"
522 + "return method.fld_data(self);"
524 private static native Object invoke0(Method m, Object self, Object[] args);
526 private static Object fromPrimitive(Class<?> type, Object o) {
527 if (type == Integer.TYPE) {
528 return fromRaw(Integer.class, "valueOf__Ljava_lang_Integer_2I", o);
530 if (type == Long.TYPE) {
531 return fromRaw(Long.class, "valueOf__Ljava_lang_Long_2J", o);
533 if (type == Double.TYPE) {
534 return fromRaw(Double.class, "valueOf__Ljava_lang_Double_2D", o);
536 if (type == Float.TYPE) {
537 return fromRaw(Float.class, "valueOf__Ljava_lang_Float_2F", o);
539 if (type == Byte.TYPE) {
540 return fromRaw(Byte.class, "valueOf__Ljava_lang_Byte_2B", o);
542 if (type == Boolean.TYPE) {
543 return fromRaw(Boolean.class, "valueOf__Ljava_lang_Boolean_2Z", o);
545 if (type == Short.TYPE) {
546 return fromRaw(Short.class, "valueOf__Ljava_lang_Short_2S", o);
548 // case 'V': return Void.TYPE;
549 throw new IllegalStateException("Can't convert " + o);
552 @JavaScriptBody(args = { "cls", "m", "o" },
553 body = "return cls.cnstr(false)[m](o);"
555 private static native Integer fromRaw(Class<?> cls, String m, Object o);
558 * Returns {@code true} if this method is a bridge
559 * method; returns {@code false} otherwise.
561 * @return true if and only if this method is a bridge
562 * method as defined by the Java Language Specification.
565 public boolean isBridge() {
566 return (getModifiers() & Modifier.BRIDGE) != 0;
570 * Returns {@code true} if this method was declared to take
571 * a variable number of arguments; returns {@code false}
574 * @return {@code true} if an only if this method was declared to
575 * take a variable number of arguments.
578 public boolean isVarArgs() {
579 return (getModifiers() & Modifier.VARARGS) != 0;
583 * Returns {@code true} if this method is a synthetic
584 * method; returns {@code false} otherwise.
586 * @return true if and only if this method is a synthetic
587 * method as defined by the Java Language Specification.
590 public boolean isSynthetic() {
591 return Modifier.isSynthetic(getModifiers());
594 @JavaScriptBody(args = { "self", "ac" },
596 "if (self.fld_data.anno) {"
597 + " return self.fld_data.anno['L' + ac.jvmName + ';'];"
598 + "} else return null;"
600 private Object getAnnotationData(Class<?> annotationClass) {
601 throw new UnsupportedOperationException();
605 * @throws NullPointerException {@inheritDoc}
608 public <T extends Annotation> T getAnnotation(Class<T> annotationClass) {
609 Object data = getAnnotationData(annotationClass);
610 return data == null ? null : AnnotationImpl.create(annotationClass, data);
616 public Annotation[] getDeclaredAnnotations() {
617 throw new UnsupportedOperationException();
621 * Returns the default value for the annotation member represented by
622 * this {@code Method} instance. If the member is of a primitive type,
623 * an instance of the corresponding wrapper type is returned. Returns
624 * null if no default is associated with the member, or if the method
625 * instance does not represent a declared member of an annotation type.
627 * @return the default value for the annotation member represented
628 * by this {@code Method} instance.
629 * @throws TypeNotPresentException if the annotation is of type
630 * {@link Class} and no definition can be found for the
631 * default class value.
634 public Object getDefaultValue() {
635 throw new UnsupportedOperationException();
639 * Returns an array of arrays that represent the annotations on the formal
640 * parameters, in declaration order, of the method represented by
641 * this {@code Method} object. (Returns an array of length zero if the
642 * underlying method is parameterless. If the method has one or more
643 * parameters, a nested array of length zero is returned for each parameter
644 * with no annotations.) The annotation objects contained in the returned
645 * arrays are serializable. The caller of this method is free to modify
646 * the returned arrays; it will have no effect on the arrays returned to
649 * @return an array of arrays that represent the annotations on the formal
650 * parameters, in declaration order, of the method represented by this
654 public Annotation[][] getParameterAnnotations() {
655 throw new UnsupportedOperationException();
659 MethodImpl.INSTANCE = new MethodImpl() {
660 protected Method create(Class<?> declaringClass, String name, Object data, String sig) {
661 return new Method(declaringClass, name, data, sig);