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.
5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation. Oracle designates this
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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22 * or visit www.oracle.com if you need additional information or have any
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 @JavaScriptBody(args = "self", body =
195 "var inst = self.cnstr();"
196 + "inst.consV(inst);"
199 public T newInstance()
200 throws InstantiationException, IllegalAccessException
202 throw new UnsupportedOperationException();
206 * Determines if the specified {@code Object} is assignment-compatible
207 * with the object represented by this {@code Class}. This method is
208 * the dynamic equivalent of the Java language {@code instanceof}
209 * operator. The method returns {@code true} if the specified
210 * {@code Object} argument is non-null and can be cast to the
211 * reference type represented by this {@code Class} object without
212 * raising a {@code ClassCastException.} It returns {@code false}
215 * <p> Specifically, if this {@code Class} object represents a
216 * declared class, this method returns {@code true} if the specified
217 * {@code Object} argument is an instance of the represented class (or
218 * of any of its subclasses); it returns {@code false} otherwise. If
219 * this {@code Class} object represents an array class, this method
220 * returns {@code true} if the specified {@code Object} argument
221 * can be converted to an object of the array class by an identity
222 * conversion or by a widening reference conversion; it returns
223 * {@code false} otherwise. If this {@code Class} object
224 * represents an interface, this method returns {@code true} if the
225 * class or any superclass of the specified {@code Object} argument
226 * implements this interface; it returns {@code false} otherwise. If
227 * this {@code Class} object represents a primitive type, this method
228 * returns {@code false}.
230 * @param obj the object to check
231 * @return true if {@code obj} is an instance of this class
235 public native boolean isInstance(Object obj);
239 * Determines if the class or interface represented by this
240 * {@code Class} object is either the same as, or is a superclass or
241 * superinterface of, the class or interface represented by the specified
242 * {@code Class} parameter. It returns {@code true} if so;
243 * otherwise it returns {@code false}. If this {@code Class}
244 * object represents a primitive type, this method returns
245 * {@code true} if the specified {@code Class} parameter is
246 * exactly this {@code Class} object; otherwise it returns
249 * <p> Specifically, this method tests whether the type represented by the
250 * specified {@code Class} parameter can be converted to the type
251 * represented by this {@code Class} object via an identity conversion
252 * or via a widening reference conversion. See <em>The Java Language
253 * Specification</em>, sections 5.1.1 and 5.1.4 , for details.
255 * @param cls the {@code Class} object to be checked
256 * @return the {@code boolean} value indicating whether objects of the
257 * type {@code cls} can be assigned to objects of this class
258 * @exception NullPointerException if the specified Class parameter is
262 public native boolean isAssignableFrom(Class<?> cls);
266 * Determines if the specified {@code Class} object represents an
269 * @return {@code true} if this object represents an interface;
270 * {@code false} otherwise.
272 public native boolean isInterface();
276 * Determines if this {@code Class} object represents an array class.
278 * @return {@code true} if this object represents an array class;
279 * {@code false} otherwise.
282 public boolean isArray() {
288 * Determines if the specified {@code Class} object represents a
291 * <p> There are nine predefined {@code Class} objects to represent
292 * the eight primitive types and void. These are created by the Java
293 * Virtual Machine, and have the same names as the primitive types that
294 * they represent, namely {@code boolean}, {@code byte},
295 * {@code char}, {@code short}, {@code int},
296 * {@code long}, {@code float}, and {@code double}.
298 * <p> These objects may only be accessed via the following public static
299 * final variables, and are the only {@code Class} objects for which
300 * this method returns {@code true}.
302 * @return true if and only if this class represents a primitive type
304 * @see java.lang.Boolean#TYPE
305 * @see java.lang.Character#TYPE
306 * @see java.lang.Byte#TYPE
307 * @see java.lang.Short#TYPE
308 * @see java.lang.Integer#TYPE
309 * @see java.lang.Long#TYPE
310 * @see java.lang.Float#TYPE
311 * @see java.lang.Double#TYPE
312 * @see java.lang.Void#TYPE
315 public native boolean isPrimitive();
318 * Returns true if this {@code Class} object represents an annotation
319 * type. Note that if this method returns true, {@link #isInterface()}
320 * would also return true, as all annotation types are also interfaces.
322 * @return {@code true} if this class object represents an annotation
323 * type; {@code false} otherwise
326 public boolean isAnnotation() {
327 return (getModifiers() & ANNOTATION) != 0;
331 * Returns {@code true} if this class is a synthetic class;
332 * returns {@code false} otherwise.
333 * @return {@code true} if and only if this class is a synthetic class as
334 * defined by the Java Language Specification.
337 public boolean isSynthetic() {
338 return (getModifiers() & SYNTHETIC) != 0;
342 * Returns the name of the entity (class, interface, array class,
343 * primitive type, or void) represented by this {@code Class} object,
344 * as a {@code String}.
346 * <p> If this class object represents a reference type that is not an
347 * array type then the binary name of the class is returned, as specified
349 * <cite>The Java™ Language Specification</cite>.
351 * <p> If this class object represents a primitive type or void, then the
352 * name returned is a {@code String} equal to the Java language
353 * keyword corresponding to the primitive type or void.
355 * <p> If this class object represents a class of arrays, then the internal
356 * form of the name consists of the name of the element type preceded by
357 * one or more '{@code [}' characters representing the depth of the array
358 * nesting. The encoding of element type names is as follows:
360 * <blockquote><table summary="Element types and encodings">
361 * <tr><th> Element Type <th> <th> Encoding
362 * <tr><td> boolean <td> <td align=center> Z
363 * <tr><td> byte <td> <td align=center> B
364 * <tr><td> char <td> <td align=center> C
365 * <tr><td> class or interface
366 * <td> <td align=center> L<i>classname</i>;
367 * <tr><td> double <td> <td align=center> D
368 * <tr><td> float <td> <td align=center> F
369 * <tr><td> int <td> <td align=center> I
370 * <tr><td> long <td> <td align=center> J
371 * <tr><td> short <td> <td align=center> S
372 * </table></blockquote>
374 * <p> The class or interface name <i>classname</i> is the binary name of
375 * the class specified above.
379 * String.class.getName()
380 * returns "java.lang.String"
381 * byte.class.getName()
383 * (new Object[3]).getClass().getName()
384 * returns "[Ljava.lang.Object;"
385 * (new int[3][4][5][6][7][8][9]).getClass().getName()
387 * </pre></blockquote>
389 * @return the name of the class or interface
390 * represented by this object.
392 public String getName() {
393 return jvmName().replace('/', '.');
396 @JavaScriptBody(args = "self", body = "return self.jvmName;")
397 private native String jvmName();
400 * Returns the {@code Class} representing the superclass of the entity
401 * (class, interface, primitive type or void) represented by this
402 * {@code Class}. If this {@code Class} represents either the
403 * {@code Object} class, an interface, a primitive type, or void, then
404 * null is returned. If this object represents an array class then the
405 * {@code Class} object representing the {@code Object} class is
408 * @return the superclass of the class represented by this object.
410 @JavaScriptBody(args = "self", body = "return self.superclass;")
411 public native Class<? super T> getSuperclass();
414 * Returns the Java language modifiers for this class or interface, encoded
415 * in an integer. The modifiers consist of the Java Virtual Machine's
416 * constants for {@code public}, {@code protected},
417 * {@code private}, {@code final}, {@code static},
418 * {@code abstract} and {@code interface}; they should be decoded
419 * using the methods of class {@code Modifier}.
421 * <p> If the underlying class is an array class, then its
422 * {@code public}, {@code private} and {@code protected}
423 * modifiers are the same as those of its component type. If this
424 * {@code Class} represents a primitive type or void, its
425 * {@code public} modifier is always {@code true}, and its
426 * {@code protected} and {@code private} modifiers are always
427 * {@code false}. If this object represents an array class, a
428 * primitive type or void, then its {@code final} modifier is always
429 * {@code true} and its interface modifier is always
430 * {@code false}. The values of its other modifiers are not determined
431 * by this specification.
433 * <p> The modifier encodings are defined in <em>The Java Virtual Machine
434 * Specification</em>, table 4.1.
436 * @return the {@code int} representing the modifiers for this class
437 * @see java.lang.reflect.Modifier
440 public native int getModifiers();
444 * Returns the simple name of the underlying class as given in the
445 * source code. Returns an empty string if the underlying class is
448 * <p>The simple name of an array is the simple name of the
449 * component type with "[]" appended. In particular the simple
450 * name of an array whose component type is anonymous is "[]".
452 * @return the simple name of the underlying class
455 public String getSimpleName() {
457 return getComponentType().getSimpleName()+"[]";
459 String simpleName = getSimpleBinaryName();
460 if (simpleName == null) { // top level class
461 simpleName = getName();
462 return simpleName.substring(simpleName.lastIndexOf(".")+1); // strip the package name
464 // According to JLS3 "Binary Compatibility" (13.1) the binary
465 // name of non-package classes (not top level) is the binary
466 // name of the immediately enclosing class followed by a '$' followed by:
467 // (for nested and inner classes): the simple name.
468 // (for local classes): 1 or more digits followed by the simple name.
469 // (for anonymous classes): 1 or more digits.
471 // Since getSimpleBinaryName() will strip the binary name of
472 // the immediatly enclosing class, we are now looking at a
473 // string that matches the regular expression "\$[0-9]*"
474 // followed by a simple name (considering the simple of an
475 // anonymous class to be the empty string).
477 // Remove leading "\$[0-9]*" from the name
478 int length = simpleName.length();
479 if (length < 1 || simpleName.charAt(0) != '$')
480 throw new IllegalStateException("Malformed class name");
482 while (index < length && isAsciiDigit(simpleName.charAt(index)))
484 // Eventually, this is the empty string iff this is an anonymous class
485 return simpleName.substring(index);
489 * Returns the "simple binary name" of the underlying class, i.e.,
490 * the binary name without the leading enclosing class name.
491 * Returns {@code null} if the underlying class is a top level
494 private String getSimpleBinaryName() {
495 Class<?> enclosingClass = null; // XXX getEnclosingClass();
496 if (enclosingClass == null) // top level class
498 // Otherwise, strip the enclosing class' name
500 return getName().substring(enclosingClass.getName().length());
501 } catch (IndexOutOfBoundsException ex) {
502 throw new IllegalStateException("Malformed class name");
507 * Character.isDigit answers {@code true} to some non-ascii
508 * digits. This one does not.
510 private static boolean isAsciiDigit(char c) {
511 return '0' <= c && c <= '9';
515 * Returns the canonical name of the underlying class as
516 * defined by the Java Language Specification. Returns null if
517 * the underlying class does not have a canonical name (i.e., if
518 * it is a local or anonymous class or an array whose component
519 * type does not have a canonical name).
520 * @return the canonical name of the underlying class if it exists, and
521 * {@code null} otherwise.
524 public String getCanonicalName() {
526 String canonicalName = getComponentType().getCanonicalName();
527 if (canonicalName != null)
528 return canonicalName + "[]";
532 // if (isLocalOrAnonymousClass())
534 // Class<?> enclosingClass = getEnclosingClass();
535 Class<?> enclosingClass = null;
536 if (enclosingClass == null) { // top level class
539 String enclosingName = enclosingClass.getCanonicalName();
540 if (enclosingName == null)
542 return enclosingName + "." + getSimpleName();
547 * Finds a resource with a given name. The rules for searching resources
548 * associated with a given class are implemented by the defining
549 * {@linkplain ClassLoader class loader} of the class. This method
550 * delegates to this object's class loader. If this object was loaded by
551 * the bootstrap class loader, the method delegates to {@link
552 * ClassLoader#getSystemResourceAsStream}.
554 * <p> Before delegation, an absolute resource name is constructed from the
555 * given resource name using this algorithm:
559 * <li> If the {@code name} begins with a {@code '/'}
560 * (<tt>'\u002f'</tt>), then the absolute name of the resource is the
561 * portion of the {@code name} following the {@code '/'}.
563 * <li> Otherwise, the absolute name is of the following form:
566 * {@code modified_package_name/name}
569 * <p> Where the {@code modified_package_name} is the package name of this
570 * object with {@code '/'} substituted for {@code '.'}
571 * (<tt>'\u002e'</tt>).
575 * @param name name of the desired resource
576 * @return A {@link java.io.InputStream} object or {@code null} if
577 * no resource with this name is found
578 * @throws NullPointerException If {@code name} is {@code null}
581 public InputStream getResourceAsStream(String name) {
582 name = resolveName(name);
583 ClassLoader cl = getClassLoader0();
586 return ClassLoader.getSystemResourceAsStream(name);
588 return cl.getResourceAsStream(name);
592 * Finds a resource with a given name. The rules for searching resources
593 * associated with a given class are implemented by the defining
594 * {@linkplain ClassLoader class loader} of the class. This method
595 * delegates to this object's class loader. If this object was loaded by
596 * the bootstrap class loader, the method delegates to {@link
597 * ClassLoader#getSystemResource}.
599 * <p> Before delegation, an absolute resource name is constructed from the
600 * given resource name using this algorithm:
604 * <li> If the {@code name} begins with a {@code '/'}
605 * (<tt>'\u002f'</tt>), then the absolute name of the resource is the
606 * portion of the {@code name} following the {@code '/'}.
608 * <li> Otherwise, the absolute name is of the following form:
611 * {@code modified_package_name/name}
614 * <p> Where the {@code modified_package_name} is the package name of this
615 * object with {@code '/'} substituted for {@code '.'}
616 * (<tt>'\u002e'</tt>).
620 * @param name name of the desired resource
621 * @return A {@link java.net.URL} object or {@code null} if no
622 * resource with this name is found
625 public java.net.URL getResource(String name) {
626 name = resolveName(name);
627 ClassLoader cl = getClassLoader0();
630 return ClassLoader.getSystemResource(name);
632 return cl.getResource(name);
637 * Add a package name prefix if the name is not absolute Remove leading "/"
638 * if name is absolute
640 private String resolveName(String name) {
644 if (!name.startsWith("/")) {
646 while (c.isArray()) {
647 c = c.getComponentType();
649 String baseName = c.getName();
650 int index = baseName.lastIndexOf('.');
652 name = baseName.substring(0, index).replace('.', '/')
656 name = name.substring(1);
662 * Returns the class loader for the class. Some implementations may use
663 * null to represent the bootstrap class loader. This method will return
664 * null in such implementations if this class was loaded by the bootstrap
667 * <p> If a security manager is present, and the caller's class loader is
668 * not null and the caller's class loader is not the same as or an ancestor of
669 * the class loader for the class whose class loader is requested, then
670 * this method calls the security manager's {@code checkPermission}
671 * method with a {@code RuntimePermission("getClassLoader")}
672 * permission to ensure it's ok to access the class loader for the class.
675 * represents a primitive type or void, null is returned.
677 * @return the class loader that loaded the class or interface
678 * represented by this object.
679 * @throws SecurityException
680 * if a security manager exists and its
681 * {@code checkPermission} method denies
682 * access to the class loader for the class.
683 * @see java.lang.ClassLoader
684 * @see SecurityManager#checkPermission
685 * @see java.lang.RuntimePermission
687 public ClassLoader getClassLoader() {
688 throw new SecurityException();
691 // Package-private to allow ClassLoader access
692 native ClassLoader getClassLoader0();
695 * Returns the {@code Class} representing the component type of an
696 * array. If this class does not represent an array class this method
699 * @return the {@code Class} representing the component type of this
700 * class if this class is an array
701 * @see java.lang.reflect.Array
704 public Class<?> getComponentType() {
709 * Returns true if and only if this class was declared as an enum in the
712 * @return true if and only if this class was declared as an enum in the
716 public boolean isEnum() {
717 // An enum must both directly extend java.lang.Enum and have
718 // the ENUM bit set; classes for specialized enum constants
719 // don't do the former.
720 return (this.getModifiers() & ENUM) != 0 &&
721 this.getSuperclass() == java.lang.Enum.class;
725 * Casts an object to the class or interface represented
726 * by this {@code Class} object.
728 * @param obj the object to be cast
729 * @return the object after casting, or null if obj is null
731 * @throws ClassCastException if the object is not
732 * null and is not assignable to the type T.
736 public T cast(Object obj) {
737 if (obj != null && !isInstance(obj))
738 throw new ClassCastException(cannotCastMsg(obj));
742 private String cannotCastMsg(Object obj) {
743 return "Cannot cast " + obj.getClass().getName() + " to " + getName();
747 * Casts this {@code Class} object to represent a subclass of the class
748 * represented by the specified class object. Checks that that the cast
749 * is valid, and throws a {@code ClassCastException} if it is not. If
750 * this method succeeds, it always returns a reference to this class object.
752 * <p>This method is useful when a client needs to "narrow" the type of
753 * a {@code Class} object to pass it to an API that restricts the
754 * {@code Class} objects that it is willing to accept. A cast would
755 * generate a compile-time warning, as the correctness of the cast
756 * could not be checked at runtime (because generic types are implemented
759 * @return this {@code Class} object, cast to represent a subclass of
760 * the specified class object.
761 * @throws ClassCastException if this {@code Class} object does not
762 * represent a subclass of the specified class (here "subclass" includes
766 public <U> Class<? extends U> asSubclass(Class<U> clazz) {
767 if (clazz.isAssignableFrom(this))
768 return (Class<? extends U>) this;
770 throw new ClassCastException(this.toString());
773 @JavaScriptBody(args = { "self", "ac" },
776 + " return self.anno['L' + ac.jvmName + ';'];"
779 private Object getAnnotationData(Class<?> annotationClass) {
780 throw new UnsupportedOperationException();
783 * @throws NullPointerException {@inheritDoc}
786 public <A extends Annotation> A getAnnotation(Class<A> annotationClass) {
787 Object data = getAnnotationData(annotationClass);
788 return data == null ? null : AnnotationImpl.create(annotationClass, data);
792 * @throws NullPointerException {@inheritDoc}
795 @JavaScriptBody(args = { "self", "ac" },
796 body = "if (self.anno && self.anno['L' + ac.jvmName + ';']) { return true; }"
797 + "else return false;"
799 public boolean isAnnotationPresent(
800 Class<? extends Annotation> annotationClass) {
801 if (annotationClass == null)
802 throw new NullPointerException();
804 return getAnnotation(annotationClass) != null;
807 @JavaScriptBody(args = "self", body = "return self.anno;")
808 private Object getAnnotationData() {
809 throw new UnsupportedOperationException();
815 public Annotation[] getAnnotations() {
816 Object data = getAnnotationData();
817 return data == null ? new Annotation[0] : AnnotationImpl.create(data);
823 public Annotation[] getDeclaredAnnotations() {
824 throw new UnsupportedOperationException();
827 static Class getPrimitiveClass(String type) {
832 public boolean desiredAssertionStatus() {