/**

  * Copyright 2009 Martin Vysny.

  *

  * This file is part of WebVM.

  *

  * WebVM 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 3 of the License, or

  * (at your option) any later version.

  *

  * WebVM 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 WebVM.  If not, see <http://www.gnu.org/licenses/>.

  */

 package sk.baka.webvm;

 import java.lang.management.GarbageCollectorMXBean;

 import java.lang.management.ManagementFactory;

 import java.lang.management.MemoryManagerMXBean;

 import java.lang.management.MemoryPoolMXBean;

 import java.lang.management.MemoryUsage;

 import java.util.ArrayList;

 import java.util.Arrays;

 import java.util.Collections;

 import java.util.List;

 import org.apache.wicket.markup.html.basic.Label;

 import org.apache.wicket.markup.html.list.ListItem;

 import org.apache.wicket.markup.html.list.ListView;

 import org.apache.wicket.model.IModel;

 import org.apache.wicket.model.LoadableDetachableModel;

 import sk.baka.webvm.misc.DivGraph;

 import sk.baka.webvm.misc.MgmtUtils;

 import sk.baka.webvm.misc.Producer;

 /**

  * Shows detailed memory information.

  * @author Martin Vysny

  */

 public final class Memory extends WebVMPage {

     private static final long serialVersionUID = 1L;

     private static final int GRAPH_WIDTH_PIXELS = 300;

     /**

      * Creates new object instance

      */

     public Memory() {

         MemoryUsage usage = MgmtUtils.getInMB(MgmtUtils.getHeapFromRuntime());

         drawMemoryStatus(usage, "heapStatusBar", GRAPH_WIDTH_PIXELS);

         border.add(new Label("heapStatusText", MgmtUtils.toString(usage, true)));

         usage = MgmtUtils.getInMB(sk.baka.webvm.analyzer.hostos.Memory.getPhysicalMemory());

         drawMemoryStatus(usage, "physicalMemoryStatusBar", GRAPH_WIDTH_PIXELS);

         border.add(new Label("physicalMemoryStatusText", MgmtUtils.toString(usage, true)));

         usage = MgmtUtils.getInMB(sk.baka.webvm.analyzer.hostos.Memory.getSwap());

         drawMemoryStatus(usage, "swapStatusBar", GRAPH_WIDTH_PIXELS);

         border.add(new Label("swapStatusText", MgmtUtils.toString(usage, true)));

         addMemoryPoolInfo(border, new MemoryBeansProducer(false), "memoryManagers", "memManName", "memManValid", "memManProperties");

         addMemoryPoolInfo(border, new MemoryBeansProducer(true), "gc", "gcName", "gcValid", "gcProperties");

         addDetailedMemoryPoolInfo(border);

         addGCStats();

     }

     private void addGCStats() {

         // garbage collections

         int collectors = 0;

         long collections = 0;

         long collectTime = 0;

         final List<GarbageCollectorMXBean> beans = ManagementFactory.getGarbageCollectorMXBeans();

         if (beans != null) {

             for (final GarbageCollectorMXBean bean : beans) {

                 if (bean.isValid()) {

                     collectors++;

                 }

                 if (bean.getCollectionCount() > 0) {

                     collections += bean.getCollectionCount();

                 }

                 if (bean.getCollectionTime() > 0) {

                     collectTime += bean.getCollectionTime();

                 }

             }

         }

         border.add(new Label("gcCount", Long.toString(collectors)));

         border.add(new Label("gcAmount", Long.toString(collections)));

         border.add(new Label("gcTime", Long.toString(collectTime)));

     }

     private static void addDetailedMemoryPoolInfo(final AppBorder border) {

         final IModel<List<MemoryPoolMXBean>> model = new LoadableDetachableModel<List<MemoryPoolMXBean>>() {

             private static final long serialVersionUID = 1L;

             @Override

             protected List<MemoryPoolMXBean> load() {

                 return ManagementFactory.getMemoryPoolMXBeans();

             }

         };

         border.add(new MemoryPoolDetailListView("memoryPool", model));

     }

     private static void addMemoryPoolInfo(final AppBorder border, final Producer<? extends List<? extends MemoryManagerMXBean>> memoryBeansProducer, final String listId, final String nameId, final String validId, final String propsId) {

         final IModel<List<MemoryManagerMXBean>> model = new LoadableDetachableModel<List<MemoryManagerMXBean>>() {

             private static final long serialVersionUID = 1L;

             @Override

             protected List<MemoryManagerMXBean> load() {

                 final List<? extends MemoryManagerMXBean> beans = memoryBeansProducer.produce();

                 return beans != null ? new ArrayList<MemoryManagerMXBean>(beans) : Collections.<MemoryManagerMXBean>emptyList();

             }

         };

         border.add(new MemoryPoolListView(listId, model, nameId, validId, propsId));

     }

     /**

      * Shows a list of detailed information about memory pools.

      */

     private static class MemoryPoolDetailListView extends ListView<MemoryPoolMXBean> {

         public MemoryPoolDetailListView(String id, IModel<? extends List<? extends MemoryPoolMXBean>> model) {

             super(id, model);

         }

         private static final int MEMSTAT_GRAPH_WIDTH = 200;

         private static final long serialVersionUID = 1L;

         @Override

         protected void populateItem(ListItem<MemoryPoolMXBean> item) {

             final MemoryPoolMXBean bean = item.getModelObject();

             item.add(new Label("poolName", bean.getName()));

             item.add(new Label("poolType", "" + bean.getType()));

             item.add(new Label("poolValid", bean.isValid() ? "Y" : "N"));

             MemoryUsage usage = MgmtUtils.getInMB(bean.getCollectionUsage());

             add(item, "poolCollects", usage, true);

             item.add(new Label("poolCollectsPerc", MgmtUtils.getUsagePerc(usage)));

             usage = MgmtUtils.getInMB(bean.getPeakUsage());

             add(item, "poolPeak", usage, false);

             item.add(new Label("poolPeakPerc", MgmtUtils.getUsagePerc(usage)));

             usage = MgmtUtils.getInMB(bean.getUsage());

             add(item, "poolUsage", usage, false);

             item.add(new Label("poolUsagePerc", MgmtUtils.getUsagePerc(usage)));

         }

         private void add(final ListItem<?> item, final String wid, MemoryUsage usage, final boolean gc) {

             if (usage == null && gc) {

                 item.add(new Label(wid, "Not collectable"));

                 return;

             }

             final StringBuilder sb = new StringBuilder();

             if (usage != null) {

                 sb.append(DivGraph.drawMemoryStatus(usage, MEMSTAT_GRAPH_WIDTH));

             }

             sb.append(MgmtUtils.toString(usage, true));

             final Label label = new Label(wid, sb.toString());

             label.setEscapeModelStrings(false);

             item.add(label);

         }

     }

     private static class MemoryBeansProducer implements Producer<List<? extends MemoryManagerMXBean>> {

         private final boolean isGcOnly;

         public MemoryBeansProducer(boolean isGcOnly) {

             this.isGcOnly = isGcOnly;

         }

         private static final long serialVersionUID = 1L;

         public List<? extends MemoryManagerMXBean> produce() {

             return isGcOnly ? ManagementFactory.getGarbageCollectorMXBeans() : ManagementFactory.getMemoryManagerMXBeans();

         }

     }

     /**

      * Shows a quick memory pool overview.

      */

     private static class MemoryPoolListView extends ListView<MemoryManagerMXBean> {

         private final String nameId;

         private final String validId;

         private final String propsId;

         public MemoryPoolListView(String id, IModel<? extends List<? extends MemoryManagerMXBean>> model, String nameId, String validId, String propsId) {

             super(id, model);

             this.nameId = nameId;

             this.validId = validId;

             this.propsId = propsId;

         }

         private static final long serialVersionUID = 1L;

         @Override

         protected void populateItem(ListItem<MemoryManagerMXBean> item) {

             final MemoryManagerMXBean bean = item.getModelObject();

             item.add(new Label(nameId, bean.getName()));

             item.add(new Label(validId, bean.isValid() ? "Y" : "N"));

             final StringBuilder sb = new StringBuilder();

             sb.append("Memory Pools: ");

             sb.append(Arrays.toString(bean.getMemoryPoolNames()));

             if (bean instanceof GarbageCollectorMXBean) {

                 final GarbageCollectorMXBean gb = (GarbageCollectorMXBean) bean;

                 sb.append("; Collections: ");

                 sb.append(gb.getCollectionCount());

                 sb.append("; Time: ");

                 sb.append(gb.getCollectionTime());

                 sb.append("ms");

             }

             item.add(new Label(propsId, sb.toString()));

         }

     }

 }