2 * Copyright (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
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28 import java.io.InputStream;
29 import java.lang.annotation.Annotation;
30 import org.apidesign.bck2brwsr.core.JavaScriptBody;
33 * Instances of the class {@code Class} represent classes and
34 * interfaces in a running Java application. An enum is a kind of
35 * class and an annotation is a kind of interface. Every array also
36 * belongs to a class that is reflected as a {@code Class} object
37 * that is shared by all arrays with the same element type and number
38 * of dimensions. The primitive Java types ({@code boolean},
39 * {@code byte}, {@code char}, {@code short},
40 * {@code int}, {@code long}, {@code float}, and
41 * {@code double}), and the keyword {@code void} are also
42 * represented as {@code Class} objects.
44 * <p> {@code Class} has no public constructor. Instead {@code Class}
45 * objects are constructed automatically by the Java Virtual Machine as classes
46 * are loaded and by calls to the {@code defineClass} method in the class
49 * <p> The following example uses a {@code Class} object to print the
50 * class name of an object:
52 * <p> <blockquote><pre>
53 * void printClassName(Object obj) {
54 * System.out.println("The class of " + obj +
55 * " is " + obj.getClass().getName());
59 * <p> It is also possible to get the {@code Class} object for a named
60 * type (or for void) using a class literal. See Section 15.8.2 of
61 * <cite>The Java™ Language Specification</cite>.
65 * {@code System.out.println("The name of class Foo is: "+Foo.class.getName());}
68 * @param <T> the type of the class modeled by this {@code Class}
69 * object. For example, the type of {@code String.class} is {@code
70 * Class<String>}. Use {@code Class<?>} if the class being modeled is
74 * @see java.lang.ClassLoader#defineClass(byte[], int, int)
78 class Class<T> implements java.io.Serializable {
79 // java.lang.reflect.GenericDeclaration,
80 // java.lang.reflect.Type,
81 // java.lang.reflect.AnnotatedElement {
82 private static final int ANNOTATION= 0x00002000;
83 private static final int ENUM = 0x00004000;
84 private static final int SYNTHETIC = 0x00001000;
87 * Constructor. Only the Java Virtual Machine creates Class
94 * Converts the object to a string. The string representation is the
95 * string "class" or "interface", followed by a space, and then by the
96 * fully qualified name of the class in the format returned by
97 * {@code getName}. If this {@code Class} object represents a
98 * primitive type, this method returns the name of the primitive type. If
99 * this {@code Class} object represents void this method returns
102 * @return a string representation of this class object.
104 public String toString() {
105 return (isInterface() ? "interface " : (isPrimitive() ? "" : "class "))
111 * Returns the {@code Class} object associated with the class or
112 * interface with the given string name. Invoking this method is
116 * {@code Class.forName(className, true, currentLoader)}
119 * where {@code currentLoader} denotes the defining class loader of
122 * <p> For example, the following code fragment returns the
123 * runtime {@code Class} descriptor for the class named
124 * {@code java.lang.Thread}:
127 * {@code Class t = Class.forName("java.lang.Thread")}
130 * A call to {@code forName("X")} causes the class named
131 * {@code X} to be initialized.
133 * @param className the fully qualified name of the desired class.
134 * @return the {@code Class} object for the class with the
136 * @exception LinkageError if the linkage fails
137 * @exception ExceptionInInitializerError if the initialization provoked
138 * by this method fails
139 * @exception ClassNotFoundException if the class cannot be located
141 public static Class<?> forName(String className)
142 throws ClassNotFoundException {
143 throw new UnsupportedOperationException();
148 * Creates a new instance of the class represented by this {@code Class}
149 * object. The class is instantiated as if by a {@code new}
150 * expression with an empty argument list. The class is initialized if it
151 * has not already been initialized.
153 * <p>Note that this method propagates any exception thrown by the
154 * nullary constructor, including a checked exception. Use of
155 * this method effectively bypasses the compile-time exception
156 * checking that would otherwise be performed by the compiler.
158 * java.lang.reflect.Constructor#newInstance(java.lang.Object...)
159 * Constructor.newInstance} method avoids this problem by wrapping
160 * any exception thrown by the constructor in a (checked) {@link
161 * java.lang.reflect.InvocationTargetException}.
163 * @return a newly allocated instance of the class represented by this
165 * @exception IllegalAccessException if the class or its nullary
166 * constructor is not accessible.
167 * @exception InstantiationException
168 * if this {@code Class} represents an abstract class,
169 * an interface, an array class, a primitive type, or void;
170 * or if the class has no nullary constructor;
171 * or if the instantiation fails for some other reason.
172 * @exception ExceptionInInitializerError if the initialization
173 * provoked by this method fails.
174 * @exception SecurityException
175 * If a security manager, <i>s</i>, is present and any of the
176 * following conditions is met:
181 * {@link SecurityManager#checkMemberAccess
182 * s.checkMemberAccess(this, Member.PUBLIC)} denies
183 * creation of new instances of this class
185 * <li> the caller's class loader is not the same as or an
186 * ancestor of the class loader for the current class and
187 * invocation of {@link SecurityManager#checkPackageAccess
188 * s.checkPackageAccess()} denies access to the package
194 public T newInstance()
195 throws InstantiationException, IllegalAccessException
197 throw new UnsupportedOperationException("Should be somehow supported");
201 * Determines if the specified {@code Object} is assignment-compatible
202 * with the object represented by this {@code Class}. This method is
203 * the dynamic equivalent of the Java language {@code instanceof}
204 * operator. The method returns {@code true} if the specified
205 * {@code Object} argument is non-null and can be cast to the
206 * reference type represented by this {@code Class} object without
207 * raising a {@code ClassCastException.} It returns {@code false}
210 * <p> Specifically, if this {@code Class} object represents a
211 * declared class, this method returns {@code true} if the specified
212 * {@code Object} argument is an instance of the represented class (or
213 * of any of its subclasses); it returns {@code false} otherwise. If
214 * this {@code Class} object represents an array class, this method
215 * returns {@code true} if the specified {@code Object} argument
216 * can be converted to an object of the array class by an identity
217 * conversion or by a widening reference conversion; it returns
218 * {@code false} otherwise. If this {@code Class} object
219 * represents an interface, this method returns {@code true} if the
220 * class or any superclass of the specified {@code Object} argument
221 * implements this interface; it returns {@code false} otherwise. If
222 * this {@code Class} object represents a primitive type, this method
223 * returns {@code false}.
225 * @param obj the object to check
226 * @return true if {@code obj} is an instance of this class
230 public native boolean isInstance(Object obj);
234 * Determines if the class or interface represented by this
235 * {@code Class} object is either the same as, or is a superclass or
236 * superinterface of, the class or interface represented by the specified
237 * {@code Class} parameter. It returns {@code true} if so;
238 * otherwise it returns {@code false}. If this {@code Class}
239 * object represents a primitive type, this method returns
240 * {@code true} if the specified {@code Class} parameter is
241 * exactly this {@code Class} object; otherwise it returns
244 * <p> Specifically, this method tests whether the type represented by the
245 * specified {@code Class} parameter can be converted to the type
246 * represented by this {@code Class} object via an identity conversion
247 * or via a widening reference conversion. See <em>The Java Language
248 * Specification</em>, sections 5.1.1 and 5.1.4 , for details.
250 * @param cls the {@code Class} object to be checked
251 * @return the {@code boolean} value indicating whether objects of the
252 * type {@code cls} can be assigned to objects of this class
253 * @exception NullPointerException if the specified Class parameter is
257 public native boolean isAssignableFrom(Class<?> cls);
261 * Determines if the specified {@code Class} object represents an
264 * @return {@code true} if this object represents an interface;
265 * {@code false} otherwise.
267 public native boolean isInterface();
271 * Determines if this {@code Class} object represents an array class.
273 * @return {@code true} if this object represents an array class;
274 * {@code false} otherwise.
277 public boolean isArray() {
283 * Determines if the specified {@code Class} object represents a
286 * <p> There are nine predefined {@code Class} objects to represent
287 * the eight primitive types and void. These are created by the Java
288 * Virtual Machine, and have the same names as the primitive types that
289 * they represent, namely {@code boolean}, {@code byte},
290 * {@code char}, {@code short}, {@code int},
291 * {@code long}, {@code float}, and {@code double}.
293 * <p> These objects may only be accessed via the following public static
294 * final variables, and are the only {@code Class} objects for which
295 * this method returns {@code true}.
297 * @return true if and only if this class represents a primitive type
299 * @see java.lang.Boolean#TYPE
300 * @see java.lang.Character#TYPE
301 * @see java.lang.Byte#TYPE
302 * @see java.lang.Short#TYPE
303 * @see java.lang.Integer#TYPE
304 * @see java.lang.Long#TYPE
305 * @see java.lang.Float#TYPE
306 * @see java.lang.Double#TYPE
307 * @see java.lang.Void#TYPE
310 public native boolean isPrimitive();
313 * Returns true if this {@code Class} object represents an annotation
314 * type. Note that if this method returns true, {@link #isInterface()}
315 * would also return true, as all annotation types are also interfaces.
317 * @return {@code true} if this class object represents an annotation
318 * type; {@code false} otherwise
321 public boolean isAnnotation() {
322 return (getModifiers() & ANNOTATION) != 0;
326 * Returns {@code true} if this class is a synthetic class;
327 * returns {@code false} otherwise.
328 * @return {@code true} if and only if this class is a synthetic class as
329 * defined by the Java Language Specification.
332 public boolean isSynthetic() {
333 return (getModifiers() & SYNTHETIC) != 0;
337 * Returns the name of the entity (class, interface, array class,
338 * primitive type, or void) represented by this {@code Class} object,
339 * as a {@code String}.
341 * <p> If this class object represents a reference type that is not an
342 * array type then the binary name of the class is returned, as specified
344 * <cite>The Java™ Language Specification</cite>.
346 * <p> If this class object represents a primitive type or void, then the
347 * name returned is a {@code String} equal to the Java language
348 * keyword corresponding to the primitive type or void.
350 * <p> If this class object represents a class of arrays, then the internal
351 * form of the name consists of the name of the element type preceded by
352 * one or more '{@code [}' characters representing the depth of the array
353 * nesting. The encoding of element type names is as follows:
355 * <blockquote><table summary="Element types and encodings">
356 * <tr><th> Element Type <th> <th> Encoding
357 * <tr><td> boolean <td> <td align=center> Z
358 * <tr><td> byte <td> <td align=center> B
359 * <tr><td> char <td> <td align=center> C
360 * <tr><td> class or interface
361 * <td> <td align=center> L<i>classname</i>;
362 * <tr><td> double <td> <td align=center> D
363 * <tr><td> float <td> <td align=center> F
364 * <tr><td> int <td> <td align=center> I
365 * <tr><td> long <td> <td align=center> J
366 * <tr><td> short <td> <td align=center> S
367 * </table></blockquote>
369 * <p> The class or interface name <i>classname</i> is the binary name of
370 * the class specified above.
374 * String.class.getName()
375 * returns "java.lang.String"
376 * byte.class.getName()
378 * (new Object[3]).getClass().getName()
379 * returns "[Ljava.lang.Object;"
380 * (new int[3][4][5][6][7][8][9]).getClass().getName()
382 * </pre></blockquote>
384 * @return the name of the class or interface
385 * represented by this object.
387 public String getName() {
388 return jvmName().replace('/', '.');
391 @JavaScriptBody(args = "self", body = "return self.jvmName;")
392 private native String jvmName();
395 * Returns the {@code Class} representing the superclass of the entity
396 * (class, interface, primitive type or void) represented by this
397 * {@code Class}. If this {@code Class} represents either the
398 * {@code Object} class, an interface, a primitive type, or void, then
399 * null is returned. If this object represents an array class then the
400 * {@code Class} object representing the {@code Object} class is
403 * @return the superclass of the class represented by this object.
405 public native Class<? super T> getSuperclass();
408 * Returns the Java language modifiers for this class or interface, encoded
409 * in an integer. The modifiers consist of the Java Virtual Machine's
410 * constants for {@code public}, {@code protected},
411 * {@code private}, {@code final}, {@code static},
412 * {@code abstract} and {@code interface}; they should be decoded
413 * using the methods of class {@code Modifier}.
415 * <p> If the underlying class is an array class, then its
416 * {@code public}, {@code private} and {@code protected}
417 * modifiers are the same as those of its component type. If this
418 * {@code Class} represents a primitive type or void, its
419 * {@code public} modifier is always {@code true}, and its
420 * {@code protected} and {@code private} modifiers are always
421 * {@code false}. If this object represents an array class, a
422 * primitive type or void, then its {@code final} modifier is always
423 * {@code true} and its interface modifier is always
424 * {@code false}. The values of its other modifiers are not determined
425 * by this specification.
427 * <p> The modifier encodings are defined in <em>The Java Virtual Machine
428 * Specification</em>, table 4.1.
430 * @return the {@code int} representing the modifiers for this class
431 * @see java.lang.reflect.Modifier
434 public native int getModifiers();
438 * Returns the simple name of the underlying class as given in the
439 * source code. Returns an empty string if the underlying class is
442 * <p>The simple name of an array is the simple name of the
443 * component type with "[]" appended. In particular the simple
444 * name of an array whose component type is anonymous is "[]".
446 * @return the simple name of the underlying class
449 public String getSimpleName() {
451 return getComponentType().getSimpleName()+"[]";
453 String simpleName = getSimpleBinaryName();
454 if (simpleName == null) { // top level class
455 simpleName = getName();
456 return simpleName.substring(simpleName.lastIndexOf(".")+1); // strip the package name
458 // According to JLS3 "Binary Compatibility" (13.1) the binary
459 // name of non-package classes (not top level) is the binary
460 // name of the immediately enclosing class followed by a '$' followed by:
461 // (for nested and inner classes): the simple name.
462 // (for local classes): 1 or more digits followed by the simple name.
463 // (for anonymous classes): 1 or more digits.
465 // Since getSimpleBinaryName() will strip the binary name of
466 // the immediatly enclosing class, we are now looking at a
467 // string that matches the regular expression "\$[0-9]*"
468 // followed by a simple name (considering the simple of an
469 // anonymous class to be the empty string).
471 // Remove leading "\$[0-9]*" from the name
472 int length = simpleName.length();
473 if (length < 1 || simpleName.charAt(0) != '$')
474 throw new IllegalStateException("Malformed class name");
476 while (index < length && isAsciiDigit(simpleName.charAt(index)))
478 // Eventually, this is the empty string iff this is an anonymous class
479 return simpleName.substring(index);
483 * Returns the "simple binary name" of the underlying class, i.e.,
484 * the binary name without the leading enclosing class name.
485 * Returns {@code null} if the underlying class is a top level
488 private String getSimpleBinaryName() {
489 Class<?> enclosingClass = null; // XXX getEnclosingClass();
490 if (enclosingClass == null) // top level class
492 // Otherwise, strip the enclosing class' name
494 return getName().substring(enclosingClass.getName().length());
495 } catch (IndexOutOfBoundsException ex) {
496 throw new IllegalStateException("Malformed class name");
501 * Character.isDigit answers {@code true} to some non-ascii
502 * digits. This one does not.
504 private static boolean isAsciiDigit(char c) {
505 return '0' <= c && c <= '9';
509 * Returns the canonical name of the underlying class as
510 * defined by the Java Language Specification. Returns null if
511 * the underlying class does not have a canonical name (i.e., if
512 * it is a local or anonymous class or an array whose component
513 * type does not have a canonical name).
514 * @return the canonical name of the underlying class if it exists, and
515 * {@code null} otherwise.
518 public String getCanonicalName() {
520 String canonicalName = getComponentType().getCanonicalName();
521 if (canonicalName != null)
522 return canonicalName + "[]";
526 // if (isLocalOrAnonymousClass())
528 // Class<?> enclosingClass = getEnclosingClass();
529 Class<?> enclosingClass = null;
530 if (enclosingClass == null) { // top level class
533 String enclosingName = enclosingClass.getCanonicalName();
534 if (enclosingName == null)
536 return enclosingName + "." + getSimpleName();
541 * Finds a resource with a given name. The rules for searching resources
542 * associated with a given class are implemented by the defining
543 * {@linkplain ClassLoader class loader} of the class. This method
544 * delegates to this object's class loader. If this object was loaded by
545 * the bootstrap class loader, the method delegates to {@link
546 * ClassLoader#getSystemResourceAsStream}.
548 * <p> Before delegation, an absolute resource name is constructed from the
549 * given resource name using this algorithm:
553 * <li> If the {@code name} begins with a {@code '/'}
554 * (<tt>'\u002f'</tt>), then the absolute name of the resource is the
555 * portion of the {@code name} following the {@code '/'}.
557 * <li> Otherwise, the absolute name is of the following form:
560 * {@code modified_package_name/name}
563 * <p> Where the {@code modified_package_name} is the package name of this
564 * object with {@code '/'} substituted for {@code '.'}
565 * (<tt>'\u002e'</tt>).
569 * @param name name of the desired resource
570 * @return A {@link java.io.InputStream} object or {@code null} if
571 * no resource with this name is found
572 * @throws NullPointerException If {@code name} is {@code null}
575 public InputStream getResourceAsStream(String name) {
576 name = resolveName(name);
577 ClassLoader cl = getClassLoader0();
580 return ClassLoader.getSystemResourceAsStream(name);
582 return cl.getResourceAsStream(name);
586 * Finds a resource with a given name. The rules for searching resources
587 * associated with a given class are implemented by the defining
588 * {@linkplain ClassLoader class loader} of the class. This method
589 * delegates to this object's class loader. If this object was loaded by
590 * the bootstrap class loader, the method delegates to {@link
591 * ClassLoader#getSystemResource}.
593 * <p> Before delegation, an absolute resource name is constructed from the
594 * given resource name using this algorithm:
598 * <li> If the {@code name} begins with a {@code '/'}
599 * (<tt>'\u002f'</tt>), then the absolute name of the resource is the
600 * portion of the {@code name} following the {@code '/'}.
602 * <li> Otherwise, the absolute name is of the following form:
605 * {@code modified_package_name/name}
608 * <p> Where the {@code modified_package_name} is the package name of this
609 * object with {@code '/'} substituted for {@code '.'}
610 * (<tt>'\u002e'</tt>).
614 * @param name name of the desired resource
615 * @return A {@link java.net.URL} object or {@code null} if no
616 * resource with this name is found
619 public java.net.URL getResource(String name) {
620 name = resolveName(name);
621 ClassLoader cl = getClassLoader0();
624 return ClassLoader.getSystemResource(name);
626 return cl.getResource(name);
631 * Add a package name prefix if the name is not absolute Remove leading "/"
632 * if name is absolute
634 private String resolveName(String name) {
638 if (!name.startsWith("/")) {
640 while (c.isArray()) {
641 c = c.getComponentType();
643 String baseName = c.getName();
644 int index = baseName.lastIndexOf('.');
646 name = baseName.substring(0, index).replace('.', '/')
650 name = name.substring(1);
656 * Returns the class loader for the class. Some implementations may use
657 * null to represent the bootstrap class loader. This method will return
658 * null in such implementations if this class was loaded by the bootstrap
661 * <p> If a security manager is present, and the caller's class loader is
662 * not null and the caller's class loader is not the same as or an ancestor of
663 * the class loader for the class whose class loader is requested, then
664 * this method calls the security manager's {@code checkPermission}
665 * method with a {@code RuntimePermission("getClassLoader")}
666 * permission to ensure it's ok to access the class loader for the class.
669 * represents a primitive type or void, null is returned.
671 * @return the class loader that loaded the class or interface
672 * represented by this object.
673 * @throws SecurityException
674 * if a security manager exists and its
675 * {@code checkPermission} method denies
676 * access to the class loader for the class.
677 * @see java.lang.ClassLoader
678 * @see SecurityManager#checkPermission
679 * @see java.lang.RuntimePermission
681 public ClassLoader getClassLoader() {
682 throw new SecurityException();
685 // Package-private to allow ClassLoader access
686 native ClassLoader getClassLoader0();
689 * Returns the {@code Class} representing the component type of an
690 * array. If this class does not represent an array class this method
693 * @return the {@code Class} representing the component type of this
694 * class if this class is an array
695 * @see java.lang.reflect.Array
698 public Class<?> getComponentType() {
703 * Returns true if and only if this class was declared as an enum in the
706 * @return true if and only if this class was declared as an enum in the
710 public boolean isEnum() {
711 // An enum must both directly extend java.lang.Enum and have
712 // the ENUM bit set; classes for specialized enum constants
713 // don't do the former.
714 return (this.getModifiers() & ENUM) != 0 &&
715 this.getSuperclass() == java.lang.Enum.class;
719 * Casts an object to the class or interface represented
720 * by this {@code Class} object.
722 * @param obj the object to be cast
723 * @return the object after casting, or null if obj is null
725 * @throws ClassCastException if the object is not
726 * null and is not assignable to the type T.
730 public T cast(Object obj) {
731 if (obj != null && !isInstance(obj))
732 throw new ClassCastException(cannotCastMsg(obj));
736 private String cannotCastMsg(Object obj) {
737 return "Cannot cast " + obj.getClass().getName() + " to " + getName();
741 * Casts this {@code Class} object to represent a subclass of the class
742 * represented by the specified class object. Checks that that the cast
743 * is valid, and throws a {@code ClassCastException} if it is not. If
744 * this method succeeds, it always returns a reference to this class object.
746 * <p>This method is useful when a client needs to "narrow" the type of
747 * a {@code Class} object to pass it to an API that restricts the
748 * {@code Class} objects that it is willing to accept. A cast would
749 * generate a compile-time warning, as the correctness of the cast
750 * could not be checked at runtime (because generic types are implemented
753 * @return this {@code Class} object, cast to represent a subclass of
754 * the specified class object.
755 * @throws ClassCastException if this {@code Class} object does not
756 * represent a subclass of the specified class (here "subclass" includes
760 public <U> Class<? extends U> asSubclass(Class<U> clazz) {
761 if (clazz.isAssignableFrom(this))
762 return (Class<? extends U>) this;
764 throw new ClassCastException(this.toString());
768 * @throws NullPointerException {@inheritDoc}
771 public <A extends Annotation> A getAnnotation(Class<A> annotationClass) {
772 throw new UnsupportedOperationException();
776 * @throws NullPointerException {@inheritDoc}
779 public boolean isAnnotationPresent(
780 Class<? extends Annotation> annotationClass) {
781 if (annotationClass == null)
782 throw new NullPointerException();
784 return getAnnotation(annotationClass) != null;
791 public Annotation[] getAnnotations() {
792 throw new UnsupportedOperationException();
798 public Annotation[] getDeclaredAnnotations() {
799 throw new UnsupportedOperationException();
802 static Class getPrimitiveClass(String type) {
807 public boolean desiredAssertionStatus() {