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java.lang.reflect
Class Method  

java.lang.Object
  java.lang.reflect.AccessibleObject
      java.lang.reflect.Method

All Implemented Interfaces:

AnnotatedElement, GenericDeclaration, Member

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public final class Method

extends AccessibleObject

implements Member, GenericDeclaration

The Method class represents a member method of a class. It also allows dynamic invocation, via reflection. This works for both static and instance methods. Invocation on Method objects knows how to do widening conversions, but throws java.lang.IllegalArgumentException if a narrowing conversion would be necessary. You can query for information on this Method regardless of location, but invocation access may be limited by Java language access controls. If you can't do it in the compiler, you can't normally do it here either.

Note: This class returns and accepts types as Classes, even primitive types; there are Class types defined that represent each different primitive type. They are java.lang.Boolean.TYPE, java.lang.Byte.TYPE,, also available as boolean.class, byte.class, etc. These are not to be confused with the classes java.lang.Boolean, java.lang.Byte, etc., which are real classes.

Also note that this is not a serializable class. It is entirely feasible to make it serializable using the Externalizable interface, but this is on Sun, not me.

Since:

1.1

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Field Summary
(package private)  java.lang.Class	declaringClass
private static int	METHOD_MODIFIERS
(package private)  java.lang.String	name
(package private)  int	slot

 

Fields inherited from class java.lang.reflect.AccessibleObject

flag

 

Fields inherited from interface java.lang.reflect.Member

DECLARED, PUBLIC

 

Constructor Summary
private	Method(java.lang.Class declaringClass, java.lang.String name, int slot)           This class is uninstantiable.

 

Method Summary
boolean	equals(java.lang.Object o)           Compare two objects to see if they are semantically equivalent.
java.lang.Class	getDeclaringClass()           Gets the class that declared this method, or the class where this method is a non-inherited member.
java.lang.Class[]	getExceptionTypes()           Get the exception types this method says it throws, in no particular order.
Type[]	getGenericExceptionTypes()           Returns an array of Type objects that represents the exception types declared by this method, in declaration order.
Type[]	getGenericParameterTypes()           Returns an array of Type objects that represents the parameter list for this method, in declaration order.
Type	getGenericReturnType()           Returns the return type of this method.
int	getModifiers()           Gets the modifiers this method uses.
private  int	getModifiersInternal()           Return the raw modifiers for this method.
java.lang.String	getName()           Gets the name of this method.
java.lang.Class[]	getParameterTypes()           Get the parameter list for this method, in declaration order.
java.lang.Class	getReturnType()           Gets the return type of this method.
private  java.lang.String	getSignature()           Return the String in the Signature attribute for this method.
TypeVariable[]	getTypeParameters()           Returns an array of TypeVariable objects that represents the type variables declared by this constructor, in declaration order.
int	hashCode()           Get the hash code for the Method.
java.lang.Object	invoke(java.lang.Object o, java.lang.Object[] args)           Invoke the method.
private  java.lang.Object	invokeNative(java.lang.Object o, java.lang.Object[] args, java.lang.Class declaringClass, int slot)
boolean	isBridge()           Return true if this method is a bridge method.
boolean	isSynthetic()           Return true if this method is synthetic, false otherwise.
boolean	isVarArgs()           Return true if this is a varargs method, that is if the method takes a variable number of arguments.
java.lang.String	toGenericString()
java.lang.String	toString()           Get a String representation of the Method.

 

Methods inherited from class java.lang.reflect.AccessibleObject

getAnnotation, getAnnotations, getDeclaredAnnotations, isAccessible, isAnnotationPresent, setAccessible, setAccessible

 

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

 

Field Detail

declaringClass

java.lang.Class declaringClass

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name

java.lang.String name

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slot

int slot

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METHOD_MODIFIERS

private static final int METHOD_MODIFIERS

See Also:

Constant Field Values

Constructor Detail

Method

private Method(java.lang.Class declaringClass,
               java.lang.String name,
               int slot)

This class is uninstantiable.

Method Detail

getDeclaringClass

public java.lang.Class getDeclaringClass()

Gets the class that declared this method, or the class where this method is a non-inherited member.

Specified by:

getDeclaringClass in interface Member

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getName

public java.lang.String getName()

Gets the name of this method.

Specified by:

getName in interface Member

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getModifiersInternal

private int getModifiersInternal()

Return the raw modifiers for this method.

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getModifiers

public int getModifiers()

Gets the modifiers this method uses. Use the Modifier class to interpret the values. A method can only have a subset of the following modifiers: public, private, protected, abstract, static, final, synchronized, native, and strictfp.

Specified by:

getModifiers in interface Member

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isBridge

public boolean isBridge()

Return true if this method is a bridge method. A bridge method is generated by the compiler in some situations involving generics and inheritance.

Since:

1.5

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isSynthetic

public boolean isSynthetic()

Return true if this method is synthetic, false otherwise.

Specified by:

isSynthetic in interface Member

Since:

1.5

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isVarArgs

public boolean isVarArgs()

Return true if this is a varargs method, that is if the method takes a variable number of arguments.

Since:

1.5

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getReturnType

public java.lang.Class getReturnType()

Gets the return type of this method.

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getParameterTypes

public java.lang.Class[] getParameterTypes()

Get the parameter list for this method, in declaration order. If the method takes no parameters, returns a 0-length array (not null).

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getExceptionTypes

public java.lang.Class[] getExceptionTypes()

Get the exception types this method says it throws, in no particular order. If the method has no throws clause, returns a 0-length array (not null).

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equals

public boolean equals(java.lang.Object o)

Compare two objects to see if they are semantically equivalent. Two Methods are semantically equivalent if they have the same declaring class, name, parameter list, and return type.

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hashCode

public int hashCode()

Get the hash code for the Method. The Method hash code is the hash code of its name XOR'd with the hash code of its class name.

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toString

public java.lang.String toString()

Get a String representation of the Method. A Method's String representation is "<modifiers> <returntype> <methodname>(<paramtypes>) throws <exceptions>", where everything after ')' is omitted if there are no exceptions.
Example: public static int run(java.lang.Runnable,int)

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toGenericString

public java.lang.String toGenericString()

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invoke

public java.lang.Object invoke(java.lang.Object o,
                               java.lang.Object[] args)
                        throws java.lang.IllegalAccessException,
                               InvocationTargetException

Invoke the method. Arguments are automatically unwrapped and widened, and the result is automatically wrapped, if needed.

If the method is static, o will be ignored. Otherwise, the method uses dynamic lookup as described in JLS 15.12.4.4. You cannot mimic the behavior of nonvirtual lookup (as in super.foo()). This means you will get a NullPointerException if o is null, and an IllegalArgumentException if it is incompatible with the declaring class of the method. If the method takes 0 arguments, you may use null or a 0-length array for args.

Next, if this Method enforces access control, your runtime context is evaluated, and you may have an IllegalAccessException if you could not acces this method in similar compiled code. If the method is static, and its class is uninitialized, you trigger class initialization, which may end in a ExceptionInInitializerError.

Finally, the method is invoked. If it completes normally, the return value will be null for a void method, a wrapped object for a primitive return method, or the actual return of an Object method. If it completes abruptly, the exception is wrapped in an InvocationTargetException.

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invokeNative

private java.lang.Object invokeNative(java.lang.Object o,
                                      java.lang.Object[] args,
                                      java.lang.Class declaringClass,
                                      int slot)
                               throws java.lang.IllegalAccessException,
                                      InvocationTargetException

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getTypeParameters

public TypeVariable[] getTypeParameters()

Returns an array of TypeVariable objects that represents the type variables declared by this constructor, in declaration order. An array of size zero is returned if this class has no type variables.

Specified by:

getTypeParameters in interface GenericDeclaration

Since:

1.5

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getSignature

private java.lang.String getSignature()

Return the String in the Signature attribute for this method. If there is no Signature attribute, return null.

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getGenericExceptionTypes

public Type[] getGenericExceptionTypes()

Returns an array of Type objects that represents the exception types declared by this method, in declaration order. An array of size zero is returned if this method declares no exceptions.

Since:

1.5

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getGenericParameterTypes

public Type[] getGenericParameterTypes()

Returns an array of Type objects that represents the parameter list for this method, in declaration order. An array of size zero is returned if this method takes no parameters.

Since:

1.5

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getGenericReturnType

public Type getGenericReturnType()

Returns the return type of this method.

Since:

1.5

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Overview  Package   Class  Use  Deprecated  Index
Home >> All >> java >> lang >> [ reflect overview ]	PREV CLASS  NEXT CLASS
SUMMARY:  JAVADOC |  SOURCE |  DOWNLOAD | NESTED | FIELD | CONSTR | METHOD	DETAIL: FIELD | CONSTR | METHOD

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