java中Class類原始碼
阿新 • • 發佈:2019-01-09
package java.lang;
import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Array;
import java.lang.reflect.GenericArrayType;
import java.lang.reflect.GenericDeclaration;
import java.lang.reflect.Member;
import java.lang.reflect.Field;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
import java.lang.reflect.Type;
import java.lang.reflect.TypeVariable;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.AnnotatedType;
import java.lang.ref.SoftReference;
import java.io.InputStream;
import java.io.ObjectStreamField;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashSet;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Set;
import java.util.Map;
import java.util.HashMap;
import java.util.Objects;
import sun.misc.Unsafe;
import sun.reflect.CallerSensitive;
import sun.reflect.ConstantPool;
import sun.reflect.Reflection;
import sun.reflect.ReflectionFactory;
import sun.reflect.generics.factory.CoreReflectionFactory;
import sun.reflect.generics.factory.GenericsFactory;
import sun.reflect.generics.repository.ClassRepository;
import sun.reflect.generics.repository.MethodRepository;
import sun.reflect.generics.repository.ConstructorRepository;
import sun.reflect.generics.scope.ClassScope;
import sun.security.util.SecurityConstants;
import java.lang.annotation.Annotation;
import java.lang.reflect.Proxy;
import sun.reflect.annotation.*;
import sun.reflect.misc.ReflectUtil;
/**
* Instances of the class {@code Class} represent classes and
* interfaces in a running Java application. An enum is a kind of
* class and an annotation is a kind of interface. Every array also
* belongs to a class that is reflected as a {@code Class} object
* that is shared by all arrays with the same element type and number
* of dimensions. The primitive Java types ({@code boolean},
* {@code byte}, {@code char}, {@code short},
* {@code int}, {@code long}, {@code float}, and
* {@code double}), and the keyword {@code void} are also
* represented as {@code Class} objects.
*
* <p> {@code Class} has no public constructor. Instead {@code Class}
* objects are constructed automatically by the Java Virtual Machine as classes
* are loaded and by calls to the {@code defineClass} method in the class
* loader.
*
* <p> The following example uses a {@code Class} object to print the
* class name of an object:
*
* <blockquote><pre>
* void printClassName(Object obj) {
* System.out.println("The class of " + obj +
* " is " + obj.getClass().getName());
* }
* </pre></blockquote>
*
* <p> It is also possible to get the {@code Class} object for a named
* type (or for void) using a class literal. See Section 15.8.2 of
* <cite>The Java™ Language Specification</cite>.
* For example:
*
* <blockquote>
* {@code System.out.println("The name of class Foo is: "+Foo.class.getName());}
* </blockquote>
*
* @param <T> the type of the class modeled by this {@code Class}
* object. For example, the type of {@code String.class} is {@code
* Class<String>}. Use {@code Class<?>} if the class being modeled is
* unknown.
*
* @author unascribed
* @see java.lang.ClassLoader#defineClass(byte[], int, int)
* @since JDK1.0
*/
public final class Class<T> implements java.io.Serializable,
GenericDeclaration,
Type,
AnnotatedElement {
private static final int ANNOTATION= 0x00002000;
private static final int ENUM = 0x00004000;
private static final int SYNTHETIC = 0x00001000;
private static native void registerNatives();
static {
registerNatives();
}
/*
* Constructor. Only the Java Virtual Machine creates Class
* objects.
*/
private Class() {}
/**
* Converts the object to a string. The string representation is the
* string "class" or "interface", followed by a space, and then by the
* fully qualified name of the class in the format returned by
* {@code getName}. If this {@code Class} object represents a
* primitive type, this method returns the name of the primitive type. If
* this {@code Class} object represents void this method returns
* "void".
*
* @return a string representation of this class object.
*/
public String toString() {
return (isInterface() ? "interface " : (isPrimitive() ? "" : "class "))
+ getName();
}
/**
* Returns a string describing this {@code Class}, including
* information about modifiers and type parameters.
*
* The string is formatted as a list of type modifiers, if any,
* followed by the kind of type (empty string for primitive types
* and {@code class}, {@code enum}, {@code interface}, or
* <code>@</code>{@code interface}, as appropriate), followed
* by the type's name, followed by an angle-bracketed
* comma-separated list of the type's type parameters, if any.
*
* A space is used to separate modifiers from one another and to
* separate any modifiers from the kind of type. The modifiers
* occur in canonical order. If there are no type parameters, the
* type parameter list is elided.
*
* <p>Note that since information about the runtime representation
* of a type is being generated, modifiers not present on the
* originating source code or illegal on the originating source
* code may be present.
*
* @return a string describing this {@code Class}, including
* information about modifiers and type parameters
*
* @since 1.8
*/
public String toGenericString() {
if (isPrimitive()) {
return toString();
} else {
StringBuilder sb = new StringBuilder();
// Class modifiers are a superset of interface modifiers
int modifiers = getModifiers() & Modifier.classModifiers();
if (modifiers != 0) {
sb.append(Modifier.toString(modifiers));
sb.append(' ');
}
if (isAnnotation()) {
sb.append('@');
}
if (isInterface()) { // Note: all annotation types are interfaces
sb.append("interface");
} else {
if (isEnum())
sb.append("enum");
else
sb.append("class");
}
sb.append(' ');
sb.append(getName());
TypeVariable<?>[] typeparms = getTypeParameters();
if (typeparms.length > 0) {
boolean first = true;
sb.append('<');
for(TypeVariable<?> typeparm: typeparms) {
if (!first)
sb.append(',');
sb.append(typeparm.getTypeName());
first = false;
}
sb.append('>');
}
return sb.toString();
}
}
/**
* Returns the {@code Class} object associated with the class or
* interface with the given string name. Invoking this method is
* equivalent to:
*
* <blockquote>
* {@code Class.forName(className, true, currentLoader)}
* </blockquote>
*
* where {@code currentLoader} denotes the defining class loader of
* the current class.
*
* <p> For example, the following code fragment returns the
* runtime {@code Class} descriptor for the class named
* {@code java.lang.Thread}:
*
* <blockquote>
* {@code Class t = Class.forName("java.lang.Thread")}
* </blockquote>
* <p>
* A call to {@code forName("X")} causes the class named
* {@code X} to be initialized.
*
* @param className the fully qualified name of the desired class.
* @return the {@code Class} object for the class with the
* specified name.
* @exception LinkageError if the linkage fails
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails
* @exception ClassNotFoundException if the class cannot be located
*/
@CallerSensitive
public static Class<?> forName(String className)
throws ClassNotFoundException {
return forName0(className, true,
ClassLoader.getClassLoader(Reflection.getCallerClass()));
}
/**
* Returns the {@code Class} object associated with the class or
* interface with the given string name, using the given class loader.
* Given the fully qualified name for a class or interface (in the same
* format returned by {@code getName}) this method attempts to
* locate, load, and link the class or interface. The specified class
* loader is used to load the class or interface. If the parameter
* {@code loader} is null, the class is loaded through the bootstrap
* class loader. The class is initialized only if the
* {@code initialize} parameter is {@code true} and if it has
* not been initialized earlier.
*
* <p> If {@code name} denotes a primitive type or void, an attempt
* will be made to locate a user-defined class in the unnamed package whose
* name is {@code name}. Therefore, this method cannot be used to
* obtain any of the {@code Class} objects representing primitive
* types or void.
*
* <p> If {@code name} denotes an array class, the component type of
* the array class is loaded but not initialized.
*
* <p> For example, in an instance method the expression:
*
* <blockquote>
* {@code Class.forName("Foo")}
* </blockquote>
*
* is equivalent to:
*
* <blockquote>
* {@code Class.forName("Foo", true, this.getClass().getClassLoader())}
* </blockquote>
*
* Note that this method throws errors related to loading, linking or
* initializing as specified in Sections 12.2, 12.3 and 12.4 of <em>The
* Java Language Specification</em>.
* Note that this method does not check whether the requested class
* is accessible to its caller.
*
* <p> If the {@code loader} is {@code null}, and a security
* manager is present, and the caller's class loader is not null, then this
* method calls the security manager's {@code checkPermission} method
* with a {@code RuntimePermission("getClassLoader")} permission to
* ensure it's ok to access the bootstrap class loader.
*
* @param name fully qualified name of the desired class
* @param initialize if {@code true} the class will be initialized.
* See Section 12.4 of <em>The Java Language Specification</em>.
* @param loader class loader from which the class must be loaded
* @return class object representing the desired class
*
* @exception LinkageError if the linkage fails
* @exception ExceptionInInitializerError if the initialization provoked
* by this method fails
* @exception ClassNotFoundException if the class cannot be located by
* the specified class loader
*
* @see java.lang.Class#forName(String)
* @see java.lang.ClassLoader
* @since 1.2
*/
@CallerSensitive
public static Class<?> forName(String name, boolean initialize,
ClassLoader loader)
throws ClassNotFoundException
{
if (sun.misc.VM.isSystemDomainLoader(loader)) {
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
ClassLoader ccl = ClassLoader.getClassLoader(Reflection.getCallerClass());
if (!sun.misc.VM.isSystemDomainLoader(ccl)) {
sm.checkPermission(
SecurityConstants.GET_CLASSLOADER_PERMISSION);
}
}
}
return forName0(name, initialize, loader);
}
/** Called after security checks have been made. */
private static native Class<?> forName0(String name, boolean initialize,
ClassLoader loader)
throws ClassNotFoundException;
/**
* Creates a new instance of the class represented by this {@code Class}
* object. The class is instantiated as if by a {@code new}
* expression with an empty argument list. The class is initialized if it
* has not already been initialized.
*
* <p>Note that this method propagates any exception thrown by the
* nullary constructor, including a checked exception. Use of
* this method effectively bypasses the compile-time exception
* checking that would otherwise be performed by the compiler.
* The {@link
* java.lang.reflect.Constructor#newInstance(java.lang.Object...)
* Constructor.newInstance} method avoids this problem by wrapping
* any exception thrown by the constructor in a (checked) {@link
* java.lang.reflect.InvocationTargetException}.
*
* @return a newly allocated instance of the class represented by this
* object.
* @throws IllegalAccessException if the class or its nullary
* constructor is not accessible.
* @throws InstantiationException
* if this {@code Class} represents an abstract class,
* an interface, an array class, a primitive type, or void;
* or if the class has no nullary constructor;
* or if the instantiation fails for some other reason.
* @throws ExceptionInInitializerError if the initialization
* provoked by this method fails.
* @throws SecurityException
* If a security manager, <i>s</i>, is present and
* the caller's class loader is not the same as or an
* ancestor of the class loader for the current class and
* invocation of {@link SecurityManager#checkPackageAccess
* s.checkPackageAccess()} denies access to the package
* of this class.
*/
@CallerSensitive
public T newInstance()
throws InstantiationException, IllegalAccessException
{
if (System.getSecurityManager() != null) {
checkMemberAccess(Member.PUBLIC, Reflection.getCallerClass(), false);
}
// NOTE: the following code may not be strictly correct under
// the current Java memory model.
// Constructor lookup
if (cachedConstructor == null) {
if (this == Class.class) {
throw new IllegalAccessException(
"Can not call newInstance() on the Class for java.lang.Class"
);
}
try {
Class<?>[] empty = {};
final Constructor<T> c = getConstructor0(empty, Member.DECLARED);
// Disable accessibility checks on the constructor
// since we have to do the security check here anyway
// (the stack depth is wrong for the Constructor's
// security check to work)
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction<Void>() {
public Void run() {
c.setAccessible(true);
return null;
}
});
cachedConstructor = c;
} catch (NoSuchMethodException e) {
throw (InstantiationException)
new InstantiationException(getName()).initCause(e);
}
}
Constructor<T> tmpConstructor = cachedConstructor;
// Security check (same as in java.lang.reflect.Constructor)
int modifiers = tmpConstructor.getModifiers();
if (!Reflection.quickCheckMemberAccess(this, modifiers)) {
Class<?> caller = Reflection.getCallerClass();
if (newInstanceCallerCache != caller) {
Reflection.ensureMemberAccess(caller, this, null, modifiers);
newInstanceCallerCache = caller;
}
}
// Run constructor
try {
return tmpConstructor.newInstance((Object[])null);
} catch (InvocationTargetException e) {
Unsafe.getUnsafe().throwException(e.getTargetException());
// Not reached
return null;
}
}
private volatile transient Constructor<T> cachedConstructor;
private volatile transient Class<?> newInstanceCallerCache;
/**
* Determines if the specified {@code Object} is assignment-compatible
* with the object represented by this {@code Class}. This method is
* the dynamic equivalent of the Java language {@code instanceof}
* operator. The method returns {@code true} if the specified
* {@code Object} argument is non-null and can be cast to the
* reference type represented by this {@code Class} object without
* raising a {@code ClassCastException.} It returns {@code false}
* otherwise.
*
* <p> Specifically, if this {@code Class} object represents a
* declared class, this method returns {@code true} if the specified
* {@code Object} argument is an instance of the represented class (or
* of any of its subclasses); it returns {@code false} otherwise. If
* this {@code Class} object represents an array class, this method
* returns {@code true} if the specified {@code Object} argument
* can be converted to an object of the array class by an identity
* conversion or by a widening reference conversion; it returns
* {@code false} otherwise. If this {@code Class} object
* represents an interface, this method returns {@code true} if the
* class or any superclass of the specified {@code Object} argument
* implements this interface; it returns {@code false} otherwise. If
* this {@code Class} object represents a primitive type, this method
* returns {@code false}.
*
* @param obj the object to check
* @return true if {@code obj} is an instance of this class
*
* @since JDK1.1
*/
public native boolean isInstance(Object obj);
/**
* Determines if the class or interface represented by this
* {@code Class} object is either the same as, or is a superclass or
* superinterface of, the class or interface represented by the specified
* {@code Class} parameter. It returns {@code true} if so;
* otherwise it returns {@code false}. If this {@code Class}
* object represents a primitive type, this method returns
* {@code true} if the specified {@code Class} parameter is
* exactly this {@code Class} object; otherwise it returns
* {@code false}.
*
* <p> Specifically, this method tests whether the type represented by the
* specified {@code Class} parameter can be converted to the type
* represented by this {@code Class} object via an identity conversion
* or via a widening reference conversion. See <em>The Java Language
* Specification</em>, sections 5.1.1 and 5.1.4 , for details.
*
* @param cls the {@code Class} object to be checked
* @return the {@code boolean} value indicating whether objects of the
* type {@code cls} can be assigned to objects of this class
* @exception NullPointerException if the specified Class parameter is
* null.
* @since JDK1.1
*/
public native boolean isAssignableFrom(Class<?> cls);
/**
* Determines if the specified {@code Class} object represents an
* interface type.
*
* @return {@code true} if this object represents an interface;
* {@code false} otherwise.
*/
public native boolean isInterface();
/**
* Determines if this {@code Class} object represents an array class.
*
* @return {@code true} if this object represents an array class;
* {@code false} otherwise.
* @since JDK1.1
*/
public native boolean isArray();
/**
* Determines if the specified {@code Class} object represents a
* primitive type.
*
* <p> There are nine predefined {@code Class} objects to represent
* the eight primitive types and void. These are created by the Java
* Virtual Machine, and have the same names as the primitive types that
* they represent, namely {@code boolean}, {@code byte},
* {@code char}, {@code short}, {@code int},
* {@code long}, {@code float}, and {@code double}.
*
* <p> These objects may only be accessed via the following public static
* final variables, and are the only {@code Class} objects for which
* this method returns {@code true}.
*
* @return true if and only if this class represents a primitive type
*
* @see java.lang.Boolean#TYPE
* @see java.lang.Character#TYPE
* @see java.lang.Byte#TYPE
* @see java.lang.Short#TYPE
* @see java.lang.Integer#TYPE
* @see java.lang.Long#TYPE
* @see java.lang.Float#TYPE
* @see java.lang.Double#TYPE
* @see java.lang.Void#TYPE
* @since JDK1.1
*/
public native boolean isPrimitive();
/**
* Returns true if this {@code Class} object represents an annotation
* type. Note that if this method returns true, {@link #isInterface()}
* would also return true, as all annotation types are also interfaces.
*
* @return {@code true} if this class object represents an annotation
* type; {@code false} otherwise
* @since 1.5
*/
public boolean isAnnotation() {
return (getModifiers() & ANNOTATION) != 0;
}
/**
* Returns {@code true} if this class is a synthetic class;
* returns {@code false} otherwise.
* @return {@code true} if and only if this class is a synthetic class as
* defined by the Java Language Specification.
* @jls 13.1 The Form of a Binary
* @since 1.5
*/
public boolean isSynthetic() {
return (getModifiers() & SYNTHETIC) != 0;
}
/**
* Returns the name of the entity (class, interface, array class,
* primitive type, or void) represented by this {@code Class} object,
* as a {@code String}.
*
* <p> If this class object represents a reference type that is not an
* array type then the binary name of the class is returned, as specified
* by
* <cite>The Java™ Language Specification</cite>.
*
* <p> If this class object represents a primitive type or void, then the
* name returned is a {@code String} equal to the Java language
* keyword corresponding to the primitive type or void.
*
* <p> If this class object represents a class of arrays, then the internal
* form of the name consists of the name of the element type preceded by
* one or more '{@code [}' characters representing the depth of the array
* nesting. The encoding of element type names is as follows:
*
* <blockquote><table summary="Element types and encodings">
* <tr><th> Element Type <th> <th> Encoding
* <tr><td> boolean <td> <td align=center> Z
* <tr><td> byte <td> <td align=center> B
* <tr><td> char <td> <td align=center> C
* <tr><td> class or interface
* <td> <td align=center> L<i>classname</i>;
* <tr><td> double <td> <td align=center> D
* <tr><td> float <td> <td align=center> F
* <tr><td> int <td> <td align=center> I
* <tr><td> long <td> <td align=center> J
* <tr><td> short <td> <td align=center> S
* </table></blockquote>
*
* <p> The class or interface name <i>classname</i> is the binary name of
* the class specified above.
*
* <p> Examples:
* <blockquote><pre>
* String.class.getName()
* returns "java.lang.String"
* byte.class.getName()
* returns "byte"
* (new Object[3]).getClass().getName()
* returns "[Ljava.lang.Object;"
* (new int[3][4][5][6][7][8][9]).getClass().getName()
* returns "[[[[[[[I"
* </pre></blockquote>
*
* @return the name of the class or interface
* represented by this object.
*/
public String getName() {
String name = this.name;
if (name == null)
this.name = name = getName0();
return name;
}
// cache the name to reduce the number of calls into the VM
private transient String name;
private native String getName0();
/**
* Returns the class loader for the class. Some implementations may use
* null to represent the bootstrap class loader. This method will return
* null in such implementations if this class was loaded by the bootstrap
* class loader.
*
* <p> If a security manager is present, and the caller's class loader is
* not null and the caller's class loader is not the same as or an ancestor of
* the class loader for the class whose class loader is requested, then
* this method calls the security manager's {@code checkPermission}
* method with a {@code RuntimePermission("getClassLoader")}
* permission to ensure it's ok to access the class loader for the class.
*
* <p>If this object
* represents a primitive type or void, null is returned.
*
* @return the class loader that loaded the class or interface
* represented by this object.
* @throws SecurityException
* if a security manager exists and its
* {@code checkPermission} method denies
* access to the class loader for the class.
* @see java.lang.ClassLoader
* @see SecurityManager#checkPermission
* @see java.lang.RuntimePermission
*/
@CallerSensitive
public ClassLoader getClassLoader() {
ClassLoader cl = getClassLoader0();
if (cl == null)
return null;
SecurityManager sm = System.getSecurityManager();
if (sm != null) {
ClassLoader.checkClassLoaderPermission(cl, Reflection.getCallerClass());
}
return cl;
}
// Package-private to allow ClassLoader access
native ClassLoader getClassLoader0();
/**
* Returns an array of {@code TypeVariable} objects that represent the
* type variables declared by the generic declaration represented by this
* {@code GenericDeclaration} object, in declaration order. Returns an
* array of length 0 if the underlying generic declaration declares no type
* variables.
*
* @return an array of {@code TypeVariable} objects that represent
* the type variables declared by this generic declaration
* @throws java.lang.reflect.GenericSignatureFormatError if the generic
* signature of this generic declaration does not conform to
* the format specified in
* <cite>The Java™ Virtual Machine Specification</cite>
* @since 1.5
*/
@SuppressWarnings("unchecked")
public TypeVariable<Class<T>>[] getTypeParameters() {
ClassRepository info = getGenericInfo();
if (info != null)
return (TypeVariable<Class<T>>[])info.getTypeParameters();
else
return (TypeVariable<Class<T>>[])new TypeVariable<?>[0];
}
/**
* Returns the {@code Class} representing the superclass of the entity
* (class, interface, primitive type or void) represented by this
* {@code Class}. If this {@code Class} represents either the
* {@code Object} class, an interface, a primitive type, or void, then
* null is returned. If this object represents an array class then the
* {@code Class} object representing the {@code Object} class is
* returned.
*
* @return the superclass of the class represented by this object.
*/
public native Class<? super T> getSuperclass();
/**
* Returns the {@code Type} representing the direct superclass of
* the entity (class, interface, primitive type or void) represented by
* this {@code Class}.
*
* <p>If the superclass is a parameterized type, the {@code Type}
* object returned must accurately reflect the actual type
* parameters used in the source code. The parameterized type
* representing the superclass is created if it had not been
* created before. See the declaration of {@link
* java.lang.reflect.ParameterizedType ParameterizedType} for the
* semantics of the creation process for parameterized types. If
* this {@code Class} represents either the {@code Object}
* class, an interface, a primitive type, or void, then null is
* returned. If this object represents an array class then the
* {@code Class} object representing the {@code Object} class is
* returned.
*
* @throws java.lang.reflect.GenericSignatureFormatError if the generic
* class signature does not conform to the format specified in
* <cite>The Java™ Virtual Machine Specification</cite>
* @throws TypeNotPresentException if the generic superclass
* refers to a non-existent type declaration
* @throws java.lang.reflect.MalformedParameterizedTypeException if the
* generic superclass refers to a parameterized type that cannot be
* instantiated for any reason
* @return the superclass of the class represented by this object
* @since 1.5
*/
public Type getGenericSuperclass() {
ClassRepository info = getGenericInfo();
if (info == null) {
return getSuperclass();
}
// Historical irregularity:
// Generic signature marks interfaces with superclass = Object
// but this API returns null for interfaces
if (isInterface()) {
return null;
}
return info.getSuperclass();
}
/**
* Gets the package for this class. The class loader of this class is used
* to find the package. If the class was loaded by the bootstrap class
* loader the set of packages loaded from CLASSPATH is searched to find the
* package of the class. Null is returned if no package object was created
* by the class loader of this class.
*
* <p> Packages have attributes for versions and specifications only if the
* information was defined in the manifests that accompany the classes, and
* if the class loader created the package instance with the attributes
* from the manifest.
*
* @return the package of the class, or null if no package
* information is available from the archive or codebase.
*/
public Package getPackage() {
return Package.getPackage(this);
}
/**
* Determines the interfaces implemented by the class or interface
* represented by this object.
*
* <p> If this object represents a class, the return value is an array
* containing objects representing all interfaces implemented by the
* class. The order of the interface objects in the array corresponds to
* the order of the interface names in the {@code implements} clause
* of the declaration of the class represented by this object. For
* example, given the declaration:
* <blockquote>
* {@code class Shimmer implements FloorWax, DessertTopping { ... }}
* </blockquote>
* suppose the value of {@code s} is an instance of
* {@code Shimmer}; the value of the expression:
* <blockquote>
* {@code s.getClass().getInterfaces()[0]}
* </blockquote>
* is the {@code Class} object that represents interface
* {@code FloorWax}; and the value of:
* <blockquote>
* {@code s.getClass().getInterfaces()[1]}
* </blockquote>
* is the {@code Class} object that represents interface
* {@code DessertTopping}.
*
* <p> If this object represents an interface, the array contains objects
* representing all interfaces extended by the interface. The order of the
* interface objects in the array corresponds to the order of the interface
* names in the {@code extends} clause of the declaration of the
* interface represented by this object.
*
* <p> If this object represents a class or interface that implements no
* interfaces, the method returns an array of length 0.
*
* <p> If this object represents a primitive type or void, the method
* returns an array of length 0.
*
* <p> If this {@code Class} object represents an array type, the
* interfaces {@code Cloneable} and {@code java.io.Serializable} are
* returned in that order.
*
* @return an array of interfaces implemented by this class.
*/
public Class<?>[] getInterfaces() {
ReflectionData<T> rd = reflectionData();
if (rd == null) {
// no cloning required
return getInterfaces0();
} else {
Class<?>[] interfaces = rd.interfaces;
if (interfaces == null) {
interfaces = getInterfaces0();
rd.interfaces = interfaces;
}
// defensively copy before handing over to user code
return interfaces.clone();
}
}
private native Class<?>[] getInterfaces0();
/**
* Returns the {@code Type}s representing the interfaces
* directly implemented by the class or interface represented by
* this object.
*
* <p>If a superinterface is a parameterized type, the
* {@code Type} object returned for it must accurately reflect
* the actual type parameters used in the source code. The
* parameterized type representing each superinterface is created
* if it had not been created before. See the declaration of
* {@link java.lang.reflect.ParameterizedType ParameterizedType}
* for the semantics of the creation process for parameterized
* types.
*
* <p> If this object represents a class, the return value is an
* array containing objects representing all interfaces
* implemented by the class. The order of the interface objects in
* the array corresponds to the order of the interface names in
* the {@code implements} clause of the declaration of the class
* represented by this object. In the case of an array class, the
* interfaces {@code Cloneable} and {@code Serializable} are
* returned in that order.
*
* <p>If this object represents an interface, the array contains
* objects representing all interfaces directly extended by the
* interface. The order of the interface objects in the array
* corresponds to the order of the interface names in the
* {@code extends} clause of the declaration of the interface
* represented by this object.
*
* <p>If this object represents a class or interface that
* implements no interfaces, the method returns an array of length
* 0.
*
* <p>If this object represents a primitive type or void, the
* method returns an array of length 0.
*
* @throws java.lang.reflect.GenericSignatureFormatError
* if the generic class signature does not conform to the format
* specified in
* <cite>The Java™ Virtual Machine Specification</cite>
* @throws TypeNotPresentException if any of the generic
* superinterfaces refers to a non-existent type declaration
* @throws java.lang.reflect.MalformedParameterizedTypeException
* if any of the generic superinterfaces refer to a parameterized
* type that cannot be instantiated for any reason
* @return an array of interfaces implemented by this class
* @since 1.5
*/
public Type[] getGenericInterfaces() {
ClassRepository info = getGenericInfo();
return (info == null) ? getInterfaces() : info.getSuperInterfaces();
}
/**
* Returns the {@code Class} representing the component type of an
* array. If this class does not represent an array class this method
* returns null.
*
* @return the {@code Class} representing the component type of this
* class if this class is an array
* @see java.lang.reflect.Array
* @since JDK1.1
*/
public native Class<?> getComponentType();
/**
* Returns the Java language modifiers for this class or interface, encoded
* in an integer. The modifiers consist of the Java Virtual Machine's
* constants for {@code public}, {@code protected},
* {@code private}, {@code final}, {@code static},
* {@code abstract} and {@code interface}; they should be decoded
* using the methods of class {@code Modifier}.
*
* <p> If the underlying class is an array class, then its
* {@code public}, {@code private} and {@code protected}
* modifiers are the same as those of its component type. If this
* {@code Class} represents a primitive type or void, its
* {@code public} modifier is always {@code true}, and its
* {@code protected} and {@code private} modifiers are always
* {@code false}. If this object represents an array class, a
* primitive type or void, then its {@code final} modifier is always
* {@code true} and its interface modifier is always
* {@code false}. The values of its other modifiers are not determined
* by this specification.
*
* <p> The modifier encodings are defined in <em>The Java Virtual Machine
* Specification</em>, table 4.1.
*
* @return the {@code int} representing the modifiers for this class
* @see java.lang.reflect.Modifier
* @since JDK1.1
*/
public native int getModifiers();
/**
* Gets the signers of this class.
*
* @return the signers of this class, or null if there are no signers. In
* particular, this method returns null if this object represents
* a primitive type or void.
* @since JDK1.1
*/
public native Object[] getSigners();
/**
* Set the signers of this class.
*/
native void setSigners(Object[] signers);
/**
* If this {@code Class} object represents a local or anonymous
* class within a method, returns a {@link
* java.lang.reflect.Method Method} object representing the
* immediately enclosing method of the underlying class. Returns
* {@code null} otherwise.
*
* In particular, this method returns {@code null} if the underlying
* class is a local or anonymous class immediately enclosed by a type
* declaration, instance initializer or static initializer.
*
* @return the immediately enclosing method of the underlying class, if
* that class is a local or anonymous class; otherwise {@code null}.
*
* @throws SecurityException
* If a security manager, <i>s</i>, is present and any of the
* following conditions is met:
*
* <ul>
*
* <li> the caller's class loader is not the same as the
* class loader of the enclosing class and invocation of
* {@link SecurityManager#checkPermission
* s.checkPermission} method with
* {@code RuntimePermission("accessDeclaredMembers")}
* denies access to the methods within the enclosing class
*
* <li> the caller's class loader is not the same as or an
* ancestor of the class loader for the enclosing class and
* invocation of {@link SecurityManager#checkPackageAccess
* s.checkPackageAccess()} denies access to the package
* of the enclosing class
*
* </ul>
* @since 1.5
*/
@CallerSensitive
public Method getEnclosingMethod() throws SecurityException {
EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
if (enclosingInfo == null)
return null;
else {
if (!enclosingInfo.isMethod())
return null;
MethodRepository typeInfo = MethodRepository.make(enclosingInfo.getDescriptor(),
getFactory());
Class<?> returnType = toClass(typeInfo.getReturnType());
Type [] parameterTypes = typeInfo.getParameterTypes();
Class<?>[] parameterClasses = new Class<?>[parameterTypes.length];
// Convert Types to Classes; returned types *should*
// be class objects since the methodDescriptor's used
// don't have generics information
for(int i = 0; i < parameterClasses.length; i++)
parameterClasses[i] = toClass(parameterTypes[i]);
// Perform access check
Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
enclosingCandidate.checkMemberAccess(Member.DECLARED,
Reflection.getCallerClass(), true);
/*
* Loop over all declared methods; match method name,
* number of and type of parameters, *and* return
* type. Matching return type is also necessary
* because of covariant returns, etc.
*/
for(Method m: enclosingCandidate.getDeclaredMethods()) {
if (m.getName().equals(enclosingInfo.getName()) ) {
Class<?>[] candidateParamClasses = m.getParameterTypes();
if (candidateParamClasses.length == parameterClasses.length) {
boolean matches = true;
for(int i = 0; i < candidateParamClasses.length; i++) {
if (!candidateParamClasses[i].equals(parameterClasses[i])) {
matches = false;
break;
}
}
if (matches) { // finally, check return type
if (m.getReturnType().equals(returnType) )
return m;
}
}
}
}
throw new InternalError("Enclosing method not found");
}
}
private native Object[] getEnclosingMethod0();
private EnclosingMethodInfo getEnclosingMethodInfo() {
Object[] enclosingInfo = getEnclosingMethod0();
if (enclosingInfo == null)
return null;
else {
return new EnclosingMethodInfo(enclosingInfo);
}
}
private final static class EnclosingMethodInfo {
private Class<?> enclosingClass;
private String name;
private String descriptor;
private EnclosingMethodInfo(Object[] enclosingInfo) {
if (enclosingInfo.length != 3)
throw new InternalError("Malformed enclosing method information");
try {
// The array is expected to have three elements:
// the immediately enclosing class
enclosingClass = (Class<?>) enclosingInfo[0];
assert(enclosingClass != null);
// the immediately enclosing method or constructor's
// name (can be null).
name = (String) enclosingInfo[1];
// the immediately enclosing method or constructor's
// descriptor (null iff name is).
descriptor = (String) enclosingInfo[2];
assert((name != null && descriptor != null) || name == descriptor);
} catch (ClassCastException cce) {
throw new InternalError("Invalid type in enclosing method information", cce);
}
}
boolean isPartial() {
return enclosingClass == null || name == null || descriptor == null;
}
boolean isConstructor() { return !isPartial() && "<init>".equals(name); }
boolean isMethod() { return !isPartial() && !isConstructor() && !"<clinit>".equals(name); }
Class<?> getEnclosingClass() { return enclosingClass; }
String getName() { return name; }
String getDescriptor() { return descriptor; }
}
private static Class<?> toClass(Type o) {
if (o instanceof GenericArrayType)
return Array.newInstance(toClass(((GenericArrayType)o).getGenericComponentType()),
0)
.getClass();
return (Class<?>)o;
}
/**
* If this {@code Class} object represents a local or anonymous
* class within a constructor, returns a {@link
* java.lang.reflect.Constructor Constructor} object representing
* the immediately enclosing constructor of the underlying
* class. Returns {@code null} otherwise. In particular, this
* method returns {@code null} if the underlying class is a local
* or anonymous class immediately enclosed by a type declaration,
* instance initializer or static initializer.
*
* @return the immediately enclosing constructor of the underlying class, if
* that class is a local or anonymous class; otherwise {@code null}.
* @throws SecurityException
* If a security manager, <i>s</i>, is present and any of the
* following conditions is met:
*
* <ul>
*
* <li> the caller's class loader is not the same as the
* class loader of the enclosing class and invocation of
* {@link SecurityManager#checkPermission
* s.checkPermission} method with
* {@code RuntimePermission("accessDeclaredMembers")}
* denies access to the constructors within the enclosing class
*
* <li> the caller's class loader is not the same as or an
* ancestor of the class loader for the enclosing class and
* invocation of {@link SecurityManager#checkPackageAccess
* s.checkPackageAccess()} denies access to the package
* of the enclosing class
*
* </ul>
* @since 1.5
*/
@CallerSensitive
public Constructor<?> getEnclosingConstructor() throws SecurityException {
EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
if (enclosingInfo == null)
return null;
else {
if (!enclosingInfo.isConstructor())
return null;
ConstructorRepository typeInfo = ConstructorRepository.make(enclosingInfo.getDescriptor(),
getFactory());
Type [] parameterTypes = typeInfo.getParameterTypes();
Class<?>[] parameterClasses = new Class<?>[parameterTypes.length];
// Convert Types to Classes; returned types *should*
// be class objects since the methodDescriptor's used
// don't have generics information
for(int i = 0; i < parameterClasses.length; i++)
parameterClasses[i] = toClass(parameterTypes[i]);
// Perform access check
Class<?> enclosingCandidate = enclosingInfo.getEnclosingClass();
enclosingCandidate.checkMemberAccess(Member.DECLARED,
Reflection.getCallerClass(), true);
/*
* Loop over all declared constructors; match number
* of and type of parameters.
*/
for(Constructor<?> c: enclosingCandidate.getDeclaredConstructors()) {
Class<?>[] candidateParamClasses = c.getParameterTypes();
if (candidateParamClasses.length == parameterClasses.length) {
boolean matches = true;
for(int i = 0; i < candidateParamClasses.length; i++) {
if (!candidateParamClasses[i].equals(parameterClasses[i])) {
matches = false;
break;
}
}
if (matches)
return c;
}
}
throw new InternalError("Enclosing constructor not found");
}
}
/**
* If the class or interface represented by this {@code Class} object
* is a member of another class, returns the {@code Class} object
* representing the class in which it was declared. This method returns
* null if this class or interface is not a member of any other class. If
* this {@code Class} object represents an array class, a primitive
* type, or void,then this method returns null.
*
* @return the declaring class for this class
* @throws SecurityException
* If a security manager, <i>s</i>, is present and the caller's
* class loader is not the same as or an ancestor of the class
* loader for the declaring class and invocation of {@link
* SecurityManager#checkPackageAccess s.checkPackageAccess()}
* denies access to the package of the declaring class
* @since JDK1.1
*/
@CallerSensitive
public Class<?> getDeclaringClass() throws SecurityException {
final Class<?> candidate = getDeclaringClass0();
if (candidate != null)
candidate.checkPackageAccess(
ClassLoader.getClassLoader(Reflection.getCallerClass()), true);
return candidate;
}
private native Class<?> getDeclaringClass0();
/**
* Returns the immediately enclosing class of the underlying
* class. If the underlying class is a top level class this
* method returns {@code null}.
* @return the immediately enclosing class of the underlying class
* @exception SecurityException
* If a security manager, <i>s</i>, is present and the caller's
* class loader is not the same as or an ancestor of the class
* loader for the enclosing class and invocation of {@link
* SecurityManager#checkPackageAccess s.checkPackageAccess()}
* denies access to the package of the enclosing class
* @since 1.5
*/
@CallerSensitive
public Class<?> getEnclosingClass() throws SecurityException {
// There are five kinds of classes (or interfaces):
// a) Top level classes
// b) Nested classes (static member classes)
// c) Inner classes (non-static member classes)
// d) Local classes (named classes declared within a method)
// e) Anonymous classes
// JVM Spec 4.8.6: A class must have an EnclosingMethod
// attribute if and only if it is a local class or an
// anonymous class.
EnclosingMethodInfo enclosingInfo = getEnclosingMethodInfo();
Class<?> enclosingCandidate;
if (enclosingInfo == null) {
// This is a top level or a nested class or an inner class (a, b, or c)
enclosingCandidate = getDeclaringClass();
} else {
Class<?> enclosingClass = enclosingInfo.getEnclosingClass();
// This is a local class or an anonymous class (d or e)
if (enclosingClass == this || enclosingClass == null)
throw new InternalError("Malformed enclosing method information");
else
enclosingCandidate = enclosingClass;
}
if (enclosingCandidate != null)
enclosingCandidate.checkPackageAccess(
ClassLoader.getClassLoader(Reflection.getCallerClass()), true);
return enclosingCandidate;
}
/**
* Returns the simple name of the underlying class as given in the
* source code. Returns an empty string if the underlying class is
* anonymous.
*
* <p>The simple name of an array is the simple name of the
* component type with "[]" appended. In particular the simple
* name of an array whose component type is anonymous is "[]".
*
* @return the simple name of the underlying class
* @since 1.5
*/
public String getSimpleName() {
if (isArray())
return getComponentType().getSimpleName()+"[]";
String simpleName = getSimpleBinaryName();
if (simpleName == null) { // top level class
simpleName = getName();
return simpleName.substring(simpleName.lastIndexOf(".")+1); // strip the package name
}
// According to JLS3 "Binary Compatibility" (13.1) the binary
// name of non-package classes (not top level) is the binary
// name of the immediately enclosing class followed by a '$' followed by:
// (for nested and inner classes): the simple name.
// (for local classes): 1 or more digits followed by the simple name.
// (for anonymous classes): 1 or more digits.
// Since getSimpleBinaryName() will strip the binary name of
// the immediatly enclosing class, we are now looking at a
// string that matches the regular expression "\$[0-9]*"
// followed by a simple name (considering the simple of an
// anonymous class to be the empty string).
// Remove leading "\$[0-9]*" from the name
int length = simpleName.length();
if (length < 1 || simpleName.charAt(0) != '$')
throw new InternalError("Malformed class name");
int index = 1;
while (index < length && isAsciiDigit(simpleName.charAt(index)))
index++;
// Eventually, this is the empty string iff this is an anonymous class
return simpleName.substring(index);
}
/**
* Return an informative string for the name of this type.
*
* @return an informative string for the name of this type
* @since 1.8
*/
public String getTypeName() {
if (isArray()) {
try {
Class<?> cl = this;
int dimensions = 0;
while (cl.isArray()) {
dimensions++;
cl = cl.getComponentType();
}
StringBuilder sb = new StringBuilder();
sb.append(cl.getName());
for (int i = 0; i < dimensions; i++) {
sb.append("[]");
}
return sb.toString();
} catch (Throwable e) { /*FALLTHRU*/ }
}
return getName();
}
/**
* Character.isDigit answers {@code true} to some non-ascii
* digits. This one does not.
*/
private static boolean isAsciiDigit(char c) {
return '0' <= c && c <= '9';
}
/**
* Returns the canonical name of the underlying class as
* defined by the Java Language Specification. Returns null if
* the underlying class does not have a canonical name (i.e., if
* it is a local or anonymous class or an array whose component
* type does not have a canonical name).
* @return the canonical name of the underlying class if it exists, and
* {@code null} otherwise.
* @since 1.5
*/
public String getCanonicalName() {
if (isArray()) {
String canonicalName = getComponentType().getCanonicalName();
if (canonicalName != null)
return canonicalName + "[]";
else
return null;
}
if (isLocalOrAnonymousClass())
return null;
Class<?> enclosingClass = getEnclosingClass();
if (enclosingClass == null) { // top level class
return getName();
} else {
String enclosingName = enclosingClass.getCanonicalName();
if (enclosingName == null)
return null;
return enclosingName + "." + getSimpleName();
}
}
/**
* Returns {@code true} if and only if the underlying class
* is an anonymous class.
*
* @return {@code true} if and only if this class is an anonymous class.
* @since 1.5
*/
public boolean isAnonymousClass() {
return "".equals(getSimpleName());
}
/**
* Returns {@code true} if and only if the underlying class
* is a local class.
*
* @return {@code true} if and only if this class is a local class.
* @since 1.5
*/
public boolean isLocalClass() {
return isLocalOrAnonymousClass() && !isAnonymousClass();
}
/**
* Returns {@code true} if and only if the underlying class
* is a member class.
*
* @return {@code true} if and only if this class is a member class.
* @since 1.5
*/
public boolean isMemberClass() {
return getSimpleBinaryName() != null && !isLocalOrAnonymousClass();
}
/**
* Returns the "simple binary name" of the underlying class, i.e.,
* the binary name without the leading enclosing class name.
* Returns {@code null} if the underlying class is a top level
* class.
*/
private String getSimpleBinaryName() {
Class<?> enclosingClass = getEnclosingClass();
if (enclosingClass == null) // top level class
return null;
// Otherwise, strip the enclosing class' name
try {
return getName().substring(enclosingClass.getName().length());
} catch (IndexOutOfBoundsException ex) {
throw new InternalError("Malformed class name", ex);
}
}
/**
* Returns {@code true} if this is a local class or an anonymous
* class. Returns {@code false} otherwise.
*/
private boolean isLocalOrAnonymousClass() {
// JVM Spec 4.8.6: A class must have an EnclosingMethod
// attribute if and only if it is a local class or an
// anonymous class.
return getEnclosingMethodInfo() != null;
}
/**
* Returns an array containing {@code Class} objects representing all
* the public classes and interfaces that are members of the class
* represented by this {@code Class} object. This includes public
* class and interface members inherited from superclasses and public class
* and interface members declared by the class. This method returns an
* array of length 0 if this {@code Class} object has no public member
* classes or interfaces. This method also returns an array of length 0 if
* this {@code Class} object represents a primitive type, an array
* class, or void.
*
* @return the array of {@code Class} objects representing the public
* members of this class
* @throws SecurityException
* If a security manager, <i>s</i>, is present and
* the caller's class loader is not the same as or an
* ancestor of the class loader for the current class and
* invocation of {@link SecurityManager#checkPackageAccess
* s.checkPackageAccess()} denies access to the package
* of this class.
*
* @since JDK1.1
*/
@CallerSensitive
public Class<?>[] getClasses() {
checkMemberAccess(Member.PUBLIC, Reflection.getCallerClass(), false);
// Privileged so this implementation can look at DECLARED classes,
// something the caller might not have privilege to do. The code here
// is allowed to look at DECLARED classes because (1) it does not hand
// out anything other than public members and (2) public member access
// has already been ok'd by the SecurityManager.
return java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction<Class<?>[]>() {
public Class<?>[] run() {
List<Class<?>> list = new ArrayList<>();
Class<?> currentClass = Class.this;
while (currentClass != null) {
Class<?>[] members = currentClass.getDeclaredClasses();
for (int i = 0; i < members.length; i++) {
if (Modifier.isPublic(members[i].getModifiers())) {
list.add(members[i]);
}
}
currentClass = currentClass.getSuperclass();
}
return list.toArray(new Class<?>[0]);
}
});
}
/**
* Returns an array containing {@code Field} objects reflecting all
* the accessible public fields of the class or interface represented by
* this {@code Class} object.
*
* <p> If this {@code Class} object represents a class or interface with no
* no accessible public fields, then this method returns an array of length
* 0.
*
* <p> If this {@code Class} object represents a class, then this method
* returns the public fields of the class and of all its superclasses.
*
* <p> If this {@code Class} object represents an interface, then this
* method returns the fields of the interface and of all its
* superinterfaces.
*
* <p> If this {@code Class} object represents an array type, a primitive
* type, or void, then this method returns an array of length 0.
*
* <p> The elements in the returned array are not sorted and are not in any
* particular order.
*
* @return the array of {@code Field} objects representing the
* public fields
* @throws SecurityException
* If a security manager, <i>s</i>, is present and
* the caller's class loader is not the same as or an
* ancestor of the class loader for the current class and
* invocation of {@link SecurityManager#checkPackageAccess
* s.checkPackageAccess()} denies access to the package
* of this class.
*
* @since JDK1.1
* @jls 8.2 Class Members
* @jls 8.3 Field Declarations
*/
@CallerSensitive
public Field[] getFields() throws SecurityException {
checkMemberAccess(Member.PUBLIC, Reflection.getCallerClass(), true);
return copyFields(privateGetPublicFields(null));
}
/**
* Returns an array containing {@code Method} objects reflecting all the
* public methods of the class or interface represented by this {@code
* Class} object, including those declared by the class or interface and
* those inherited from superclasses and superinterfaces.
*
* <p> If this {@code Class} object represents a type that has multiple
* public methods with the same name and parameter types, but different
* return types, then the returned array has a {@code Method} object for
* each such method.
*
* <p> If this {@code Class} object represents a type