java.lang.Class Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Copyright (C) 2006-2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Copyright (C) 2012 RoboVM AB
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.lang;
import java.io.InputStream;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import java.lang.annotation.Inherited;
import java.lang.ref.SoftReference;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.net.URL;
import java.security.ProtectionDomain;
import java.util.Collection;
import java.util.HashMap;
import libcore.reflect.GenericSignatureParser;
import libcore.reflect.Types;
import dalvik.system.VMStack;
/**
* The in-memory representation of a Java class. This representation serves as
* the starting point for querying class-related information, a process usually
* called "reflection". There are basically three types of {@code Class}
* instances: those representing real classes and interfaces, those representing
* primitive types, and those representing array classes.
*
* Class instances representing object types (classes or interfaces)
*
* These represent an ordinary class or interface as found in the class
* hierarchy. The name associated with these {@code Class} instances is simply
* the fully qualified class name of the class or interface that it represents.
* In addition to this human-readable name, each class is also associated by a
* so-called signature, which is the letter "L", followed by the
* class name and a semicolon (";"). The signature is what the runtime system
* uses internally for identifying the class (for example in a DEX file).
*
* Classes representing primitive types
*
* These represent the standard Java primitive types and hence share their
* names (for example "int" for the {@code int} primitive type). Although it is
* not possible to create new instances based on these {@code Class} instances,
* they are still useful for providing reflection information, and as the
* component type of array classes. There is one {@code Class} instance for each
* primitive type, and their signatures are:
*
*
* - {@code B} representing the {@code byte} primitive type
* - {@code S} representing the {@code short} primitive type
* - {@code I} representing the {@code int} primitive type
* - {@code J} representing the {@code long} primitive type
* - {@code F} representing the {@code float} primitive type
* - {@code D} representing the {@code double} primitive type
* - {@code C} representing the {@code char} primitive type
* - {@code Z} representing the {@code boolean} primitive type
* - {@code V} representing void function return values
*
*
*
Classes representing array classes
*
* These represent the classes of Java arrays. There is one such {@code Class}
* instance per combination of array leaf component type and arity (number of
* dimensions). In this case, the name associated with the {@code Class}
* consists of one or more left square brackets (one per dimension in the array)
* followed by the signature of the class representing the leaf component type,
* which can be either an object type or a primitive type. The signature of a
* {@code Class} representing an array type is the same as its name. Examples
* of array class signatures are:
*
*
* - {@code [I} representing the {@code int[]} type
* - {@code [Ljava/lang/String;} representing the {@code String[]} type
* - {@code [[[C} representing the {@code char[][][]} type (three dimensions!)
*
*/
public final class Class implements Serializable, AnnotatedElement, GenericDeclaration, Type {
private static final long serialVersionUID = 3206093459760846163L;
private SoftReference> cacheRef;
private Class() {
// Prevent this class to be instantiated, instance
// should be created by JVM only
}
ClassCache getClassCache() {
ClassCache cache = cacheRef != null ? cacheRef.get() : null;
if (cache == null) {
cache = new ClassCache(this);
cacheRef = new SoftReference>(cache);
}
return cache;
}
/**
* Get the Signature attribute for this class. Returns null if not found.
*/
private native String getSignatureAttribute();
/**
* Returns a {@code Class} object which represents the class with the
* given name. The name should be the name of a non-primitive class, as described in
* the {@link Class class definition}.
* Primitive types can not be found using this method; use {@code int.class} or {@code Integer.TYPE} instead.
*
* If the class has not yet been loaded, it is loaded and initialized
* first. This is done through either the class loader of the calling class
* or one of its parent class loaders. It is possible that a static initializer is run as
* a result of this call.
*
* @param className
* the name of the non-primitive-type class to find.
* @return the named {@code Class} instance.
* @throws ClassNotFoundException
* if the requested class can not be found.
* @throws LinkageError
* if an error occurs during linkage
* @throws ExceptionInInitializerError
* if an exception occurs during static initialization of a
* class.
*/
public static Class forName(String className) throws ClassNotFoundException {
return forName(className, true, VMStack.getCallingClassLoader());
}
/**
* Returns a {@code Class} object which represents the class with the
* given name. The name should be the name of a non-primitive class, as described in
* the {@link Class class definition}.
* Primitive types can not be found using this method; use {@code int.class} or {@code Integer.TYPE} instead.
*
*
If the class has not yet been loaded, it is loaded first, using the given class loader.
* If the class has not yet been initialized and {@code shouldInitialize} is true,
* the class will be initialized.
*
* @param className
* the name of the non-primitive-type class to find.
* @param shouldInitialize
* indicates whether the class should be initialized.
* @param classLoader
* the class loader to use to load the class.
* @return the named {@code Class} instance.
* @throws ClassNotFoundException
* if the requested class can not be found.
* @throws LinkageError
* if an error occurs during linkage
* @throws ExceptionInInitializerError
* if an exception occurs during static initialization of a
* class.
*/
public static Class forName(String className, boolean shouldInitialize,
ClassLoader classLoader) throws ClassNotFoundException {
if (classLoader == null) {
classLoader = ClassLoader.getSystemClassLoader();
}
// Catch an Exception thrown by the underlying native code. It wraps
// up everything inside a ClassNotFoundException, even if e.g. an
// Error occurred during initialization. This as a workaround for
// an ExceptionInInitializerError that's also wrapped. It is actually
// expected to be thrown. Maybe the same goes for other errors.
// Not wrapping up all the errors will break android though.
Class result;
try {
result = classForName(className, shouldInitialize,
classLoader);
} catch (ClassNotFoundException e) {
Throwable cause = e.getCause();
if (cause instanceof ExceptionInInitializerError) {
throw (ExceptionInInitializerError) cause;
}
throw e;
}
return result;
}
static native Class classForName(String className, boolean shouldInitialize,
ClassLoader classLoader) throws ClassNotFoundException;
/**
* Returns an array containing {@code Class} objects for all public classes
* and interfaces that are members of this class. This includes public
* members inherited from super classes and interfaces. If there are no such
* class members or if this object represents a primitive type then an array
* of length 0 is returned.
*
* @return the public class members of the class represented by this object.
*/
public Class[] getClasses() {
return getClassCache().getClasses(true);
}
@Override public A getAnnotation(Class annotationType) {
if (annotationType == null) {
throw new NullPointerException("annotationType == null");
}
A annotation = getDeclaredAnnotation(annotationType);
if (annotation != null) {
return annotation;
}
if (annotationType.isAnnotationPresent(Inherited.class)) {
for (Class sup = getSuperclass(); sup != null; sup = sup.getSuperclass()) {
annotation = sup.getDeclaredAnnotation(annotationType);
if (annotation != null) {
return annotation;
}
}
}
return null;
}
/**
* Returns an array containing all the annotations of this class. If there are no annotations
* then an empty array is returned.
*
* @see #getDeclaredAnnotations()
*/
public Annotation[] getAnnotations() {
return getClassCache().getAnnotations(true);
}
final Annotation[] getAnnotations0() {
/*
* We need to get the annotations declared on this class, plus the
* annotations from superclasses that have the "@Inherited" annotation
* set. We create a temporary map to use while we accumulate the
* annotations and convert it to an array at the end.
*
* It's possible to have duplicates when annotations are inherited.
* We use a Map to filter those out.
*
* HashMap might be overkill here.
*/
HashMap map = new HashMap();
Annotation[] declaredAnnotations = getClassCache().getDeclaredAnnotations(false);
for (int i = declaredAnnotations.length-1; i >= 0; --i) {
map.put(declaredAnnotations[i].annotationType(), declaredAnnotations[i]);
}
for (Class sup = getSuperclass(); sup != null; sup = sup.getSuperclass()) {
declaredAnnotations = sup.getClassCache().getDeclaredAnnotations(false);
for (int i = declaredAnnotations.length-1; i >= 0; --i) {
Class clazz = declaredAnnotations[i].annotationType();
if (!map.containsKey(clazz) && clazz.isAnnotationPresent(Inherited.class)) {
map.put(clazz, declaredAnnotations[i]);
}
}
}
/* convert annotation values from HashMap to array */
Collection coll = map.values();
return coll.toArray(new Annotation[coll.size()]);
}
/**
* Returns the canonical name of this class. If this class does not have a
* canonical name as defined in the Java Language Specification, then the
* method returns {@code null}.
*/
public String getCanonicalName() {
if (isLocalClass() || isAnonymousClass())
return null;
if (isArray()) {
/*
* The canonical name of an array type depends on the (existence of)
* the component type's canonical name.
*/
String name = getComponentType().getCanonicalName();
if (name != null) {
return name + "[]";
}
} else if (isMemberClass()) {
/*
* The canonical name of an inner class depends on the (existence
* of) the declaring class' canonical name.
*/
String name = getDeclaringClass().getCanonicalName();
if (name != null) {
return name + "." + getSimpleName();
}
} else {
/*
* The canonical name of a top-level class or primitive type is
* equal to the fully qualified name.
*/
return getName();
}
/*
* Other classes don't have a canonical name.
*/
return null;
}
/**
* Returns the class loader which was used to load the class represented by
* this {@code Class}. Implementations are free to return {@code null} for
* classes that were loaded by the bootstrap class loader. The Android
* reference implementation, though, always returns a reference to an actual
* class loader.
*/
public ClassLoader getClassLoader() {
if (this.isPrimitive()) {
return null;
}
ClassLoader loader = getClassLoaderImpl();
if (loader == null) {
loader = BootClassLoader.getInstance();
}
return loader;
}
/**
* This must be provided by the VM vendor, as it is used by other provided
* class implementations in this package. Outside of this class, it is used
* by SecurityManager.classLoaderDepth(),
* currentClassLoader() and currentLoadedClass(). Return the ClassLoader for
* this Class without doing any security checks. The bootstrap ClassLoader
* is returned, unlike getClassLoader() which returns null in place of the
* bootstrap ClassLoader.
*/
ClassLoader getClassLoaderImpl() {
ClassLoader loader = getClassLoader(this);
return loader == null ? BootClassLoader.getInstance() : loader;
}
/*
* Returns the defining class loader for the given class.
*/
private static native ClassLoader getClassLoader(Class c);
/**
* Returns a {@code Class} object which represents the component type if
* this class represents an array type. Returns {@code null} if this class
* does not represent an array type. The component type of an array type is
* the type of the elements of the array.
*/
public native Class getComponentType();
/**
* Returns a {@code Constructor} object which represents the public
* constructor matching the given parameter types.
* {@code (Class[]) null} is equivalent to the empty array.
*
* See {@link #getMethod} for details of the search order.
* Use {@link #getDeclaredConstructor} if you don't want to search superclasses.
*
* @throws NoSuchMethodException
* if the constructor can not be found.
*/
@SuppressWarnings("unchecked")
public Constructor getConstructor(Class... parameterTypes) throws NoSuchMethodException {
return getClassCache().getConstructor(true, parameterTypes);
}
/**
* Returns an array containing {@code Constructor} objects for all public
* constructors for this {@code Class}. If there
* are no public constructors or if this {@code Class} represents an array
* class, a primitive type or void then an empty array is returned.
*
* @see #getDeclaredConstructors()
*/
public Constructor[] getConstructors() {
return getClassCache().getDeclaredPublicConstructors(true);
}
/**
* Returns the annotations that are directly defined on the class
* represented by this {@code Class}. Annotations that are inherited are not
* included in the result. If there are no annotations at all, an empty
* array is returned.
*
* @see #getAnnotations()
*/
public Annotation[] getDeclaredAnnotations() {
return getClassCache().getDeclaredAnnotations(true);
}
final native Annotation[] getDeclaredAnnotations0();
/**
* Returns the annotation if it exists.
*/
private A getDeclaredAnnotation(Class annotationClass) {
if (annotationClass == null) {
throw new NullPointerException("annotationClass == null");
}
Annotation[] annos = getClassCache().getDeclaredAnnotations(false);
for (int i = annos.length-1; i >= 0; --i) {
if (annos[i].annotationType() == annotationClass) {
return (A) annos[i];
}
}
return null;
}
/**
* Returns true if the annotation exists.
*/
private boolean isDeclaredAnnotationPresent(Class annotationClass) {
if (annotationClass == null) {
throw new NullPointerException("annotationClass == null");
}
return getDeclaredAnnotation(annotationClass) != null;
}
/**
* Returns an array containing {@code Class} objects for all classes and
* interfaces that are declared as members of the class which this {@code
* Class} represents. If there are no classes or interfaces declared or if
* this class represents an array class, a primitive type or void, then an
* empty array is returned.
*/
public Class[] getDeclaredClasses() {
return getClassCache().getDeclaredClasses(true);
}
final native Class[] getDeclaredClasses0(boolean publicOnly);
/**
* Returns a {@code Constructor} object which represents the constructor
* matching the given parameter types that is declared by the class
* represented by this {@code Class}.
* {@code (Class[]) null} is equivalent to the empty array.
*
* Use {@link #getConstructor} if you want to search superclasses.
*
* @throws NoSuchMethodException
* if the requested constructor can not be found.
*/
@SuppressWarnings("unchecked")
public Constructor getDeclaredConstructor(Class... parameterTypes)
throws NoSuchMethodException {
return getClassCache().getDeclaredConstructor(true, parameterTypes);
}
/**
* Returns an array containing {@code Constructor} objects for all
* constructors declared in the class represented by this {@code Class}. If
* there are no constructors or if this {@code Class} represents an array
* class, a primitive type, or void then an empty array is returned.
*
* @see #getConstructors()
*/
public Constructor[] getDeclaredConstructors() {
return getClassCache().getDeclaredConstructors(true);
}
final native Constructor[] getDeclaredConstructors0(boolean publicOnly);
/**
* Returns a {@code Field} object for the field with the given name
* which is declared in the class represented by this {@code Class}.
*
* @throws NoSuchFieldException if the requested field can not be found.
* @see #getField(String)
*/
public Field getDeclaredField(String name) throws NoSuchFieldException {
if (name == null) {
throw new NullPointerException("name == null");
}
return getClassCache().getDeclaredField(true, name);
}
/**
* Returns an array containing {@code Field} objects for all fields declared
* in the class represented by this {@code Class}. If there are no fields or
* if this {@code Class} represents an array class, a primitive type or void
* then an empty array is returned.
*
* @see #getFields()
*/
public Field[] getDeclaredFields() {
return getClassCache().getDeclaredFields(true);
}
final native Field[] getDeclaredFields0(boolean publicOnly);
/**
* Returns a {@code Method} object which represents the method matching the
* given name and parameter types that is declared by the class
* represented by this {@code Class}.
* {@code (Class[]) null} is equivalent to the empty array.
*
* See {@link #getMethod} if you want to search superclasses.
*
* @throws NoSuchMethodException
* if the requested method can not be found.
* @throws NullPointerException
* if {@code name} is {@code null}.
*/
public Method getDeclaredMethod(String name, Class... parameterTypes)
throws NoSuchMethodException {
return getClassCache().getDeclaredMethod(true, name, parameterTypes);
}
/**
* Returns an array containing {@code Method} objects for all methods
* declared in the class represented by this {@code Class}. If there are no
* methods or if this {@code Class} represents an array class, a primitive
* type or void then an empty array is returned.
*
* @see #getMethods()
*/
public Method[] getDeclaredMethods() {
return getClassCache().getDeclaredMethods(true);
}
final native Method[] getDeclaredMethods0(boolean publicOnly);
/**
* Returns the declaring {@code Class} of this {@code Class}. Returns
* {@code null} if the class is not a member of another class or if this
* {@code Class} represents an array class, a primitive type, or void.
*/
public native Class getDeclaringClass();
/**
* Returns the enclosing {@code Class} of this {@code Class}. If there is no
* enclosing class the method returns {@code null}.
*/
public native Class getEnclosingClass();
/**
* Returns the enclosing {@code Constructor} of this {@code Class}, if it is an
* anonymous or local/automatic class; otherwise {@code null}.
*/
public native Constructor getEnclosingConstructor();
/**
* Returns the enclosing {@code Method} of this {@code Class}, if it is an
* anonymous or local/automatic class; otherwise {@code null}.
*/
public native Method getEnclosingMethod();
/**
* Returns the {@code enum} constants associated with this {@code Class}.
* Returns {@code null} if this {@code Class} does not represent an {@code
* enum} type.
*/
@SuppressWarnings("unchecked") // we only cast after confirming that this class is an enum
public T[] getEnumConstants() {
if (!isEnum()) {
return null;
}
return (T[]) Enum.getSharedConstants((Class) this).clone();
}
/**
* Returns a {@code Field} object which represents the public field with the
* given name. This method first searches the class C represented by
* this {@code Class}, then the interfaces implemented by C and finally the
* superclasses of C.
*
* @throws NoSuchFieldException
* if the field can not be found.
* @see #getDeclaredField(String)
*/
public Field getField(String name) throws NoSuchFieldException {
if (name == null) {
throw new NullPointerException("name == null");
}
return getClassCache().getField(true, name);
}
/**
* Returns an array containing {@code Field} objects for all public fields
* for the class C represented by this {@code Class}. Fields may be declared
* in C, the interfaces it implements or in the superclasses of C. The
* elements in the returned array are in no particular order.
*
*
If there are no public fields or if this class represents an array class,
* a primitive type or {@code void} then an empty array is returned.
*
* @see #getDeclaredFields()
*/
public Field[] getFields() {
return getClassCache().getFields(true);
}
/**
* Returns the {@link Type}s of the interfaces that this {@code Class} directly
* implements. If the {@code Class} represents a primitive type or {@code
* void} then an empty array is returned.
*/
public Type[] getGenericInterfaces() {
GenericSignatureParser parser = new GenericSignatureParser(getClassLoader());
parser.parseForClass(this, getSignatureAttribute());
return Types.getTypeArray(parser.interfaceTypes, true);
}
/**
* Returns the {@code Type} that represents the superclass of this {@code
* class}.
*/
public Type getGenericSuperclass() {
GenericSignatureParser parser = new GenericSignatureParser(getClassLoader());
parser.parseForClass(this, getSignatureAttribute());
return Types.getType(parser.superclassType);
}
/**
* Returns an array of {@code Class} objects that match the interfaces
* in the {@code implements} declaration of the class represented
* by this {@code Class}. The order of the elements in the array is
* identical to the order in the original class declaration. If the class
* does not implement any interfaces, an empty array is returned.
*/
public native Class[] getInterfaces();
/**
* Returns a {@code Method} object which represents the public method with
* the given name and parameter types.
* {@code (Class[]) null} is equivalent to the empty array.
*
*
This method first searches the class C represented by this {@code Class},
* then the superclasses of C,
* and finally the interfaces implemented by C and its superclasses.
*
*
Use {@link #getDeclaredMethod} if you don't want to search superclasses.
*
* @throws NoSuchMethodException
* if the method can not be found.
*/
public Method getMethod(String name, Class... parameterTypes) throws NoSuchMethodException {
return getClassCache().getMethod(true, name, parameterTypes);
}
/**
* Returns an array containing {@code Method} objects for all public methods
* for the class C represented by this {@code Class}. Methods may be
* declared in C, the interfaces it implements or in the superclasses of C.
* The elements in the returned array are in no particular order.
*
*
If there are no public methods or if this {@code Class} represents a
* primitive type or {@code void} then an empty array is returned.
*
* @see #getDeclaredMethods()
*/
public Method[] getMethods() {
return getClassCache().getMethods(true);
}
/**
* Returns an integer that represents the modifiers of the class represented
* by this {@code Class}. The returned value is a combination of bits
* defined by constants in the {@link Modifier} class.
*/
public int getModifiers() {
return getModifiers(this, false);
}
/*
* Returns the modifiers for the given class.
*
* {@code ignoreInnerClassesAttrib} determines whether we look for and use the
* flags from an "inner class" attribute
*/
private static native int getModifiers(Class clazz, boolean ignoreInnerClassesAttrib);
/**
* Returns the name of the class represented by this {@code Class}. For a
* description of the format which is used, see the class definition of
* {@link Class}.
*/
public String getName() {
return getClassCache().getName();
}
/**
* Returns the BugVM class name. E.g. java/lang/String, I, [[I,
* [Ljava/lang/Object;.
*/
final native String getName0();
/**
* Returns the simple name of the class represented by this {@code Class} as
* defined in the source code. If there is no name (that is, the class is
* anonymous) then an empty string is returned. If the receiver is an array
* then the name of the underlying type with square braces appended (for
* example {@code "Integer[]"}) is returned.
*
* @return the simple name of the class represented by this {@code Class}.
*/
public String getSimpleName() {
if (isArray()) {
return getComponentType().getSimpleName() + "[]";
}
String name = getName();
if (isAnonymousClass()) {
return "";
}
if (isMemberClass() || isLocalClass()) {
return getInnerClassName();
}
int dot = name.lastIndexOf('.');
if (dot != -1) {
return name.substring(dot + 1);
}
return name;
}
/*
* Returns the simple name of a member or local class, or null otherwise.
*/
private native String getInnerClassName();
/**
* Returns null.
*/
public ProtectionDomain getProtectionDomain() {
return null;
}
/**
* Returns the URL of the given resource, or null if the resource is not found.
* The mapping between the resource name and the URL is managed by the class' class loader.
*
* @see ClassLoader
*/
public URL getResource(String resourceName) {
// Get absolute resource name, but without the leading slash
if (resourceName.startsWith("/")) {
resourceName = resourceName.substring(1);
} else {
String pkg = getName();
int dot = pkg.lastIndexOf('.');
if (dot != -1) {
pkg = pkg.substring(0, dot).replace('.', '/');
} else {
pkg = "";
}
resourceName = pkg + "/" + resourceName;
}
// Delegate to proper class loader
ClassLoader loader = getClassLoader();
if (loader != null) {
return loader.getResource(resourceName);
} else {
return ClassLoader.getSystemResource(resourceName);
}
}
/**
* Returns a read-only stream for the contents of the given resource, or null if the resource
* is not found.
* The mapping between the resource name and the stream is managed by the class' class loader.
*
* @see ClassLoader
*/
public InputStream getResourceAsStream(String resourceName) {
// Get absolute resource name, but without the leading slash
if (resourceName.startsWith("/")) {
resourceName = resourceName.substring(1);
} else {
String pkg = getName();
int dot = pkg.lastIndexOf('.');
if (dot != -1) {
pkg = pkg.substring(0, dot).replace('.', '/');
} else {
pkg = "";
}
resourceName = pkg + "/" + resourceName;
}
// Delegate to proper class loader
ClassLoader loader = getClassLoader();
if (loader != null) {
return loader.getResourceAsStream(resourceName);
} else {
return ClassLoader.getSystemResourceAsStream(resourceName);
}
}
/**
* Returns null. (On Android, a {@code ClassLoader} can load classes from multiple dex files.
* All classes from any given dex file will have the same signers, but different dex
* files may have different signers. This does not fit well with the original
* {@code ClassLoader}-based model of {@code getSigners}.)
*/
public Object[] getSigners() {
// See http://code.google.com/p/android/issues/detail?id=1766.
return null;
}
/**
* Returns the {@code Class} object which represents the superclass of the
* class represented by this {@code Class}. If this {@code Class} represents
* the {@code Object} class, a primitive type, an interface or void then the
* method returns {@code null}. If this {@code Class} represents an array
* class then the {@code Object} class is returned.
*/
public native Class getSuperclass();
/**
* Returns an array containing {@code TypeVariable} objects for type
* variables declared by the generic class represented by this {@code
* Class}. Returns an empty array if the class is not generic.
*/
@SuppressWarnings("unchecked")
public synchronized TypeVariable>[] getTypeParameters() {
GenericSignatureParser parser = new GenericSignatureParser(getClassLoader());
parser.parseForClass(this, getSignatureAttribute());
return parser.formalTypeParameters.clone();
}
/**
* Tests whether this {@code Class} represents an annotation class.
*/
public boolean isAnnotation() {
final int ACC_ANNOTATION = 0x2000; // not public in reflect.Modifiers
int mod = getModifiers(this, true);
return (mod & ACC_ANNOTATION) != 0;
}
@Override public boolean isAnnotationPresent(Class annotationType) {
if (annotationType == null) {
throw new NullPointerException("annotationType == null");
}
if (isDeclaredAnnotationPresent(annotationType)) {
return true;
}
if (annotationType.isDeclaredAnnotationPresent(Inherited.class)) {
for (Class sup = getSuperclass(); sup != null; sup = sup.getSuperclass()) {
if (sup.isDeclaredAnnotationPresent(annotationType)) {
return true;
}
}
}
return false;
}
/**
* Tests whether the class represented by this {@code Class} is
* anonymous.
*/
native public boolean isAnonymousClass();
/**
* Tests whether the class represented by this {@code Class} is an array class.
*/
public boolean isArray() {
return getComponentType() != null;
}
/**
* Tests whether the given class type can be converted to the class
* represented by this {@code Class}. Conversion may be done via an identity
* conversion or a widening reference conversion (if either the receiver or
* the argument represent primitive types, only the identity conversion
* applies).
*
* @throws NullPointerException
* if {@code c} is {@code null}.
*/
public native boolean isAssignableFrom(Class c);
/**
* Tests whether the class represented by this {@code Class} is an
* {@code enum}.
*/
public boolean isEnum() {
if (getSuperclass() != Enum.class) {
return false;
}
int mod = getModifiers(this, true);
return (mod & 0x4000) != 0;
}
/**
* Tests whether the given object can be cast to the class
* represented by this {@code Class}. This is the runtime version of the
* {@code instanceof} operator.
*
* @return {@code true} if {@code object} can be cast to the type
* represented by this {@code Class}; {@code false} if {@code
* object} is {@code null} or cannot be cast.
*/
public native boolean isInstance(Object object);
/**
* Tests whether this {@code Class} represents an interface.
*/
public native boolean isInterface();
/**
* Tests whether the class represented by this {@code Class} is defined
* locally.
*/
public boolean isLocalClass() {
boolean enclosed = (getEnclosingMethod() != null ||
getEnclosingConstructor() != null);
return enclosed && !isAnonymousClass();
}
/**
* Tests whether the class represented by this {@code Class} is a member
* class.
*/
public boolean isMemberClass() {
return getDeclaringClass() != null;
}
/**
* Tests whether this {@code Class} represents a primitive type.
*/
public native boolean isPrimitive();
/**
* Tests whether this {@code Class} represents a synthetic type.
*/
public boolean isSynthetic() {
final int ACC_SYNTHETIC = 0x1000; // not public in reflect.Modifiers
int mod = getModifiers(this, true);
return (mod & ACC_SYNTHETIC) != 0;
}
/**
* Returns a new instance of the class represented by this {@code Class},
* created by invoking the default (that is, zero-argument) constructor. If
* there is no such constructor, or if the creation fails (either because of
* a lack of available memory or because an exception is thrown by the
* constructor), an {@code InstantiationException} is thrown. If the default
* constructor exists but is not accessible from the context where this
* method is invoked, an {@code IllegalAccessException} is thrown.
*
* @throws IllegalAccessException
* if the default constructor is not visible.
* @throws InstantiationException
* if the instance can not be created.
*/
public T newInstance() throws InstantiationException, IllegalAccessException {
try {
Constructor constructor = getDeclaredConstructor();
return constructor.newInstance();
} catch (NoSuchMethodException e) {
throw new InstantiationException(e.getMessage());
} catch (InvocationTargetException e) {
throw new InstantiationException(e.getMessage());
}
}
@Override
public String toString() {
if (isPrimitive()) {
return getSimpleName();
}
return (isInterface() ? "interface " : "class ") + getName();
}
/**
* Returns the {@code Package} of which the class represented by this
* {@code Class} is a member. Returns {@code null} if no {@code Package}
* object was created by the class loader of the class.
*/
public Package getPackage() {
// TODO This might be a hack, but the VM doesn't have the necessary info.
ClassLoader loader = getClassLoader();
if (loader != null) {
String name = getName();
int dot = name.lastIndexOf('.');
return (dot != -1 ? loader.getPackage(name.substring(0, dot)) : null);
}
return null;
}
/**
* Returns the assertion status for the class represented by this {@code
* Class}. Assertion is enabled / disabled based on the class loader,
* package or class default at runtime.
*/
public native boolean desiredAssertionStatus();
/**
* Casts this {@code Class} to represent a subclass of the given class.
* If successful, this {@code Class} is returned; otherwise a {@code
* ClassCastException} is thrown.
*
* @throws ClassCastException
* if this {@code Class} cannot be cast to the given type.
*/
@SuppressWarnings("unchecked")
public Class asSubclass(Class c) {
if (c.isAssignableFrom(this)) {
return (Class)this;
}
String actualClassName = this.getName();
String desiredClassName = c.getName();
throw new ClassCastException(actualClassName + " cannot be cast to " + desiredClassName);
}
/**
* Casts the given object to the type represented by this {@code Class}.
* If the object is {@code null} then the result is also {@code null}.
*
* @throws ClassCastException
* if the object cannot be cast to the given type.
*/
@SuppressWarnings("unchecked")
public T cast(Object obj) {
if (obj == null) {
return null;
} else if (this.isInstance(obj)) {
return (T)obj;
}
String actualClassName = obj.getClass().getName();
String desiredClassName = this.getName();
throw new ClassCastException(actualClassName + " cannot be cast to " + desiredClassName);
}
/**
* Copies two arrays into one. Assumes that the destination array is large
* enough.
*
* @param result the destination array
* @param head the first source array
* @param tail the second source array
* @return the destination array, that is, result
*/
private static T[] arraycopy(T[] result, T[] head, T[] tail) {
System.arraycopy(head, 0, result, 0, head.length);
System.arraycopy(tail, 0, result, head.length, tail.length);
return result;
}
}