java.lang.reflect
Class Method
- Member
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
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.
clone , equals , finalize , getClass , hashCode , notify , notifyAll , toString , wait , wait , wait |
equals
public boolean equals(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.
- equals in interface Object
o
- the object to compare to
true
if they are equal; false
if not
getExceptionTypes
public 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).
- a list of the types in the method's throws clause
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.
- getModifiers in interface Member
- an integer representing the modifiers to this Member
getParameterTypes
public 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).
- a list of the types of the method's parameters
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.
- hashCode in interface Object
- the hash code for the object
invoke
public Object invoke(Object o,
Object[] args)
throws 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
.
o
- the object to invoke the method onargs
- the arguments to the method
- the return value of the method, wrapped in the appropriate
wrapper if it is primitive
toString
public 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)
- toString in interface Object
- the String representation of the Method
java.lang.reflect.Method - reflection of Java methods
Copyright (C) 1998, 2001, 2002 Free Software Foundation, Inc.
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module. An independent module is a module which is not derived from
or based on this library. If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so. If you do not wish to do so, delete this
exception statement from your version.