Reduce memory usage, allow selection of multiple metrics in MetricsPa…

…ne [HZG-208] (#7)

This PR reduces the memory footprint while loading large diagnostics
files.

Previously each individual `DiagnosticFile` contained an index for the
metric entries contained within it. Now there is a single index per
instance of `InstanceDiagnostics`, this hugely reduces the number of
index entries needed and allows the tool to load several gigabytes of
diagnostic logs.

In addition a number of IDE compiler warnings have been fixed and the
`MetricsPane` has been updated to allow selection and comparison of
multiple metrics.

src/main/java/com/hazelcast/diagnostics/BuildInfoPane.java

@@ -1,18 +1,21 @@
 package com.hazelcast.diagnostics;
 
-import javax.swing.*;
+import javax.swing.JComponent;
+import javax.swing.JScrollPane;
+import javax.swing.JTable;
 import javax.swing.table.DefaultTableModel;
 import java.util.Iterator;
 import java.util.Map;
 
+import static com.hazelcast.diagnostics.InstanceDiagnostics.DiagnosticType.TYPE_BUILD_INFO;
+
 public class BuildInfoPane {
 
-    private final JTable table;
     private final DefaultTableModel model;
     private final JScrollPane pane;
 
     public BuildInfoPane() {
-        table = new JTable();
+        JTable table = new JTable();
         model = new DefaultTableModel();
         table.setModel(model);
         model.addColumn("Key");
@@ -31,7 +34,7 @@ public void setInstanceDiagnostics(InstanceDiagnostics diagnostics) {
             return;
         }
 
-        Iterator<Map.Entry<Long, String>> it = diagnostics.between(InstanceDiagnostics.TYPE_BUILD_INFO, 0, Long.MAX_VALUE);
+        Iterator<Map.Entry<Long, String>> it = diagnostics.between(TYPE_BUILD_INFO, 0, Long.MAX_VALUE);
         if (!it.hasNext()) {
             System.out.println("No BuildInfo found in directory: " + diagnostics.getDirectory());
             return;

src/main/java/com/hazelcast/diagnostics/ConnectionPane.java

@@ -1,13 +1,17 @@
 package com.hazelcast.diagnostics;
 
-import javax.swing.*;
+import javax.swing.JComponent;
+import javax.swing.JScrollPane;
+import javax.swing.JTextArea;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.TreeMap;
 
+import static com.hazelcast.diagnostics.InstanceDiagnostics.DiagnosticType.TYPE_CONNECTION;
+
 public class ConnectionPane {
 
     private final JComponent component;
@@ -37,9 +41,9 @@ public void update() {
             return;
         }
 
-        TreeMap<Long, List<String>> treeMap = new TreeMap();
+        TreeMap<Long, List<String>> treeMap = new TreeMap<>();
         for (InstanceDiagnostics diagnostics : diagnosticsList) {
-            Iterator<Map.Entry<Long, String>> iterator = diagnostics.between(InstanceDiagnostics.TYPE_CONNECTION, startMs, endMs);
+            Iterator<Map.Entry<Long, String>> iterator = diagnostics.between(TYPE_CONNECTION, startMs, endMs);
 
             if (!iterator.hasNext()) {
                 continue;
@@ -48,11 +52,7 @@ public void update() {
             while (iterator.hasNext()) {
                 Map.Entry<Long, String> entry = iterator.next();
                 Long key = entry.getKey();
-                List<String> list = treeMap.get(key);
-                if (list == null) {
-                    list = new ArrayList<>();
-                    treeMap.put(key, list);
-                }
+                List<String> list = treeMap.computeIfAbsent(key, k -> new ArrayList<>());
                 list.add(entry.getValue());
             }
         }

src/main/java/com/hazelcast/diagnostics/CpuUtilizationPane.java

@@ -10,7 +10,8 @@
 import org.jfree.data.time.TimeSeries;
 import org.jfree.data.time.TimeSeriesCollection;
 
-import javax.swing.*;
+import javax.swing.JComponent;
+import javax.swing.JPanel;
 import java.text.SimpleDateFormat;
 import java.util.Collection;
 import java.util.Iterator;
@@ -19,25 +20,17 @@
 
 public class CpuUtilizationPane {
     private final JPanel component;
-    private final JFreeChart chart;
-    private final ChartPanel chartPanel;
     private final TimeSeriesCollection collection;
     private long startMs = Long.MIN_VALUE;
     private long endMs = Long.MAX_VALUE;
     private Collection<InstanceDiagnostics> diagnosticsList = new LinkedList<>();
 
     public CpuUtilizationPane() {
         collection = new TimeSeriesCollection();
-        chart = ChartFactory.createTimeSeriesChart(
-                "CPU Utilization",
-                "Time",
-                "Utilization",
-                collection,
-                true,
-                true,
+        JFreeChart chart = ChartFactory.createTimeSeriesChart("CPU Utilization", "Time", "Utilization", collection, true, true,
                 false);
-        this.chartPanel = new ChartPanel(chart);
-        XYPlot plot = (XYPlot)chartPanel.getChart().getPlot();
+        ChartPanel chartPanel = new ChartPanel(chart);
+        XYPlot plot = (XYPlot) chartPanel.getChart().getPlot();
         DateAxis axis = (DateAxis)plot.getDomainAxis();
         axis.setDateFormatOverride(new SimpleDateFormat("HH:mm:ss"));
         this.component = chartPanel;
@@ -56,7 +49,8 @@ public void update() {
         collection.removeAllSeries();
 
         for (InstanceDiagnostics diagnostics : diagnosticsList) {
-            Iterator<Map.Entry<Long, Number>> iterator = diagnostics.metricsBetween("[metric=os.processCpuLoad]", startMs, endMs);
+            Iterator<Map.Entry<Long, Number>> iterator = diagnostics.metricsBetween(
+                    InstanceDiagnostics.METRIC_OS_PROCESS_CPU_LOAD, startMs, endMs);
 
             if (!iterator.hasNext()) {
                 continue;