/*
    * Licensed under the GPL License. You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    *
    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
    * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE.
   */
  package psiprobe.beans;
  
  import java.lang.management.ManagementFactory;
  import java.util.LinkedList;
  import java.util.List;
  import java.util.Set;
  
  import javax.management.MBeanServer;
  import javax.management.MalformedObjectNameException;
  import javax.management.ObjectInstance;
  import javax.management.ObjectName;
  import javax.management.openmbean.CompositeDataSupport;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import psiprobe.model.jmx.MemoryPool;
  import psiprobe.tools.JmxTools;
  
  /**
   * The Class JvmMemoryInfoAccessorBean.
   */
  public class JvmMemoryInfoAccessorBean {
  
    /** The Constant logger. */
    private static final Logger logger = LoggerFactory.getLogger(JvmMemoryInfoAccessorBean.class);
  
    /**
     * Gets the pools.
     *
     * @return the pools
     *
     * @throws MalformedObjectNameException the malformed object name exception
     */
    public List<MemoryPool> getPools() throws MalformedObjectNameException {
  
      MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer();
      Set<ObjectInstance> objectInstanceMemoryPools =
          mbeanServer.queryMBeans(new ObjectName("java.lang:type=MemoryPool,*"), null);
      // totals
      long totalInit = 0;
      long totalMax = 0;
      long totalUsed = 0;
      long totalCommitted = 0;
  
      List<MemoryPool> memoryPools = new LinkedList<>();
      for (ObjectInstance objectInstance : objectInstanceMemoryPools) {
        ObjectName objName = objectInstance.getObjectName();
        MemoryPool memoryPool = new MemoryPool();
        memoryPool.setName(JmxTools.getStringAttr(mbeanServer, objName, "Name"));
        memoryPool.setType(JmxTools.getStringAttr(mbeanServer, objName, "Type"));
  
        CompositeDataSupport cd =
            (CompositeDataSupport) JmxTools.getAttribute(mbeanServer, objName, "Usage");
        /*
         * It seems that "Usage" attribute of one of the pools may turn into null intermittently. We
         * better have a dip in the graph then an NPE though.
         */
        if (cd != null) {
          memoryPool.setMax(JmxTools.getLongAttr(cd, "max"));
          memoryPool.setUsed(JmxTools.getLongAttr(cd, "used"));
          memoryPool.setInit(JmxTools.getLongAttr(cd, "init"));
          memoryPool.setCommitted(JmxTools.getLongAttr(cd, "committed"));
        } else {
          logger.error("Oops, JVM problem? {} 'Usage' attribute is NULL!", objName);
        }
  
        totalInit += memoryPool.getInit();
        totalMax += memoryPool.getMax();
        totalUsed += memoryPool.getUsed();
        totalCommitted += memoryPool.getCommitted();
  
        memoryPools.add(memoryPool);
      }
  
      if (!memoryPools.isEmpty()) {
        MemoryPool pool = new MemoryPool();
        pool.setName("Total");
        pool.setType("TOTAL");
        pool.setInit(totalInit);
        pool.setUsed(totalUsed);
        pool.setMax(totalMax);
        pool.setCommitted(totalCommitted);
        memoryPools.add(pool);
      }
  
      return memoryPools;
  
    }
 }