1 /*
   2  * Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 
  27 package com.sun.org.glassfish.gmbal ;
  28 
  29 import java.lang.annotation.Documented ;
  30 import java.lang.annotation.Target ;
  31 import java.lang.annotation.ElementType ;
  32 import java.lang.annotation.Retention ;
  33 import java.lang.annotation.RetentionPolicy ;
  34 
  35 /** This annotation defines an attribute in either CompositeData (ManagedData) or
  36  * an open MBean (ManagedObject).  An attribute may be read/write (has a setter
  37  * and a getter), read only (only has a getter),
  38  * or write only (only has a setter) depending on the declared methods in the class.
  39  * <p>
  40  * A method defines a getter if it returns a non-void type and takes no argument types.
  41  * Likewise a method defines a setter if it return void and takes exactly one
  42  * argument.
  43  * <p>An id is derived from a method name as follows:
  44  * <ol>
  45  * <li>If the method is a getter, and has a name of the form getXXX, the derived
  46  * id is xXX (note the initial lower case change).
  47  * <li>If the method is a getter with a boolean return type, and has a name of
  48  * the form isXXX, the derived id is xXX
  49  * <li>If the method is a setter, and has a name of the form setXXX, the
  50  * detived id is xXX.
  51  * <li>Otherwise the derived ID is the method name.
  52  * </ol>
  53  * <p>
  54  * In certain cases, a field annotated with @ManagedAttribute
  55  * may also represent a read-only attribute.
  56  * The field must be final, and its type must be one of:
  57  * <ol>
  58  * <li>A primitive type (boolean, byte, short, char, int, long, float, double)
  59  * <li>A primitive type wrapper (Boolean, Byte, Short, Character, Integer,
  60  * Long, Float, Double)
  61  * <li>A String
  62  * <li>A BigDecimal or BigInteger
  63  * <li>A java.util.Date
  64  * <li>An ObjectName
  65  * <li>An enum (which is translated to its ordinal name)
  66  * </ol>
  67  * Any such field can be accessed safely by multiple threads, because its value
  68  * cannot change after an instance of the containing class has completed its
  69  * constructor.  Note that Date is not truly immutable (it should be!), but it's
  70  * one of the Open MBean simple types, so it is included here.
  71  */
  72 @Documented
  73 @Target({ElementType.METHOD,ElementType.FIELD})
  74 @Retention(RetentionPolicy.RUNTIME)
  75 public @interface ManagedAttribute {
  76     /** The id of the attribute.  Defaults to value derived from method name.
  77      * @return The id (default "").
  78      */
  79     String id() default "" ;
  80 }