1 /*
   2  * Copyright (c) 2015, 2018, 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 package com.sun.jmx.mbeanserver;
  26 
  27 import java.lang.reflect.Constructor;
  28 import java.lang.reflect.Method;
  29 import jdk.internal.access.JavaBeansAccess;
  30 import jdk.internal.access.SharedSecrets;
  31 
  32 /**
  33  * A centralized place for gaining access to java.beans related functionality -
  34  * if available.
  35  */
  36 class JavaBeansAccessor {
  37     static {
  38         // ensure that java.beans.Introspector is initialized (if present)
  39         // it will fill in the SharedSecrets
  40         try {
  41             Class.forName("java.beans.Introspector", true,
  42                           JavaBeansAccessor.class.getClassLoader());
  43         } catch (ClassNotFoundException ignore) { }
  44     }
  45 
  46     private static JavaBeansAccess getJavaBeansAccess() {
  47         return SharedSecrets.getJavaBeansAccess();
  48     }
  49 
  50     static boolean isAvailable() {
  51         return getJavaBeansAccess() != null;
  52     }
  53 
  54     /**
  55      * Returns the getter method for a property of the given name
  56      * @param clazz The JavaBeans class
  57      * @param property The property name
  58      * @return The resolved property getter name or null
  59      * @throws Exception
  60      */
  61     static Method getReadMethod(Class<?> clazz, String property) throws Exception {
  62         JavaBeansAccess jba = getJavaBeansAccess();
  63         return jba != null ? jba.getReadMethod(clazz, property) : null;
  64     }
  65 
  66     /**
  67      * Return the <b>value</b> attribute of the associated
  68      * <code>@ConstructorProperties</code> annotation if that is present.
  69      * @param ctr The constructor to extract the annotation value from
  70      * @return The {@code value} attribute of the <code>@ConstructorProperties</code>
  71      *         annotation or {@code null} if the constructor is not annotated by
  72      *         this annotation or the annotation is not accessible.
  73      */
  74     static String[] getConstructorPropertiesValue(Constructor<?> ctr) {
  75         JavaBeansAccess jba = getJavaBeansAccess();
  76         return jba != null ? jba.getConstructorPropertiesValue(ctr) : null;
  77     }
  78 }