Facultative.java

/*
** Module   : Facultative.java
** Abstract : MBean supporting enable/disable 
**
** Copyright (c) 2020-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description----------------------------------
** 001 IAS 20200930 Created initial version.
** 002 IAS 20201001 Added dump of MBean state.
** 003 HC  20240222 Enabled JMX on FWD Client.
*/ 

/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
** 
** Additional terms under GNU Affero GPL version 3 section 7:
** 
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
** 
**   0. Attribution Requirement.
** 
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**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
**     credit already included within the covered work.
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*/

package com.goldencode.p2j.jmx;

import java.lang.ref.*;
import java.util.*;
import java.util.concurrent.atomic.*;

import com.goldencode.util.*;

/**
 * MBean supporting enable/disable
 */
public class Facultative 
implements FacultativeMBean, 
           AgentRegistry<BooleanConsumer>
{
   /** agent's set */
   private final Set<BooleanConsumer> agents = Collections.newSetFromMap(
         new WeakHashMap<BooleanConsumer, Boolean>()
   ); 
   
   /** "MBean enabled flag */
   private final AtomicBoolean enabled = new AtomicBoolean(false); 
   
   /** MBean annotation */
   private String annotation = "Counters";

   /**
    * Check if enabled
    * @return <code>true</code> if enabled
    */
   @Override
   public boolean isEnabled()
   {
      return enabled.get();
   }

   /**
    * Enable/disable
    * @param val
    *        new value of the "enabled" flag.
    */
   @Override
   public synchronized void enable(boolean val)
   {
      
      if (enabled.getAndSet(val) != val)
      {
         agents.stream().forEach(c -> c.accept(val));
      }
   }

   /**
    * Register agent
    * 
    * @param agent
    *        agent to be registered
    */
   @Override
   public synchronized void register(BooleanConsumer agent)
   {
      // sync the enabled state on registration for the case when
      // the simple counter gets loaded/unloaded dynamically (like a web app)
      // or the class has simply not been yet loaded by the class loader
      agent.accept(enabled.get());
      agents.add(agent);
   }

   /**
    * Get counter annotation
    * @return counter annotation
    */
   @Override
   public String getAnnotation()
   {
      return annotation;
   }

   /**
    * Set counter annotation
    * @param annotation
    *        counter annotation
    */
   @Override
   public void setAnnotation(String annotation)
   {
      this.annotation = annotation;
   }
}