Refactor tooltip handling in TmfCommonXLineChart

Refactor TmfCommonXLineChartTooltipProvider to make the tooltip population logic extensible for subclasses via protected hooks, while preserving the default tooltip behavior.

Also remove unused maxLen calculation that was left over from an earlier implementation.

Files:
- org.eclipse.tracecompass.tmf.ui.viewers.xychart.linechart.TmfCommonXLineChartTooltipProvider

Author: TranHoangThanhDuy

tmf/org.eclipse.tracecompass.tmf.ui/src/org/eclipse/tracecompass/tmf/ui/viewers/xychart/linechart/TmfCommonXLineChartTooltipProvider.java

@@ -23,15 +23,14 @@
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.graphics.RGBA;
 import org.eclipse.swt.widgets.Control;
-import org.eclipse.tracecompass.internal.tmf.ui.Messages;
 import org.eclipse.tracecompass.tmf.core.presentation.RGBAColor;
-import org.eclipse.tracecompass.tmf.core.timestamp.ITmfTimestamp;
-import org.eclipse.tracecompass.tmf.core.timestamp.TmfTimestamp;
 import org.eclipse.tracecompass.tmf.ui.viewers.TmfAbstractToolTipHandler;
+import org.eclipse.tracecompass.tmf.ui.viewers.TmfAbstractToolTipHandler.ToolTipString;
 import org.eclipse.tracecompass.tmf.ui.viewers.xychart.IAxis;
 import org.eclipse.tracecompass.tmf.ui.viewers.xychart.ITmfChartTimeProvider;
 import org.eclipse.tracecompass.tmf.ui.viewers.xychart.IXYSeries;
 import org.eclipse.tracecompass.tmf.ui.viewers.xychart.TmfBaseProvider;
+import org.eclipse.tracecompass.tmf.ui.viewers.xychart.linechart.TmfCommonXAxisChartViewer;
 
 /**
  * Displays a tooltip on line charts. For each series, it shows the y value at
@@ -43,80 +42,8 @@
  */
 public class TmfCommonXLineChartTooltipProvider extends TmfBaseProvider {
 
-    private final class XYToolTipHandler extends TmfAbstractToolTipHandler {
-        private static final String HTML_COLOR_TOOLTIP = "<span style=\"color:%s;\">%s</span>"; //$NON-NLS-1$
-
-        private boolean isValid(int index, IXYSeries serie) {
-            double[] ySeries = serie.getYSeries();
-            return serie.isVisible() && ySeries != null && ySeries.length > index;
-        }
-
-        @Override
-        public void fill(Control control, MouseEvent event, Point pt) {
-            if (getChartViewer().getWindowDuration() != 0) {
-                IAxis xAxis = getXAxis();
-
-                double xCoordinate = xAxis.getDataCoordinate(pt.x);
-
-                List<IXYSeries> series = getSeries();
-
-                if ((xCoordinate < 0) || (series.isEmpty())) {
-                    return;
-                }
-
-                /* Find the index of the value we want */
-                double[] xS = series.get(0).getXSeries();
-                if (xS == null) {
-                    return;
-                }
-                int index = Arrays.binarySearch(xS, xCoordinate);
-                index = index >= 0 ? index : -index - 1;
-                int maxLen = 0;
-                for (IXYSeries serie : series) {
-                    /* Make sure the series values and the value at index exist */
-                    if (isValid(index, serie)) {
-                        maxLen = Math.max(maxLen, serie.getId().length());
-                    }
-                }
-
-                TmfCommonXAxisChartViewer viewer = null;
-                Format format = null;
-                ITmfChartTimeProvider timeProvider = getChartViewer();
-                if (timeProvider instanceof TmfCommonXAxisChartViewer) {
-                    viewer = (TmfCommonXAxisChartViewer) timeProvider;
-                    format = viewer.getSwtChart().getAxisSet().getYAxes()[0].getTick().getFormat();
-                }
-                ITmfTimestamp time = TmfTimestamp.fromNanos((long) xCoordinate + getChartViewer().getTimeOffset());
-                addItem(null, ToolTipString.fromString(Messages.TmfCommonXLineChartTooltipProvider_time), ToolTipString.fromTimestamp(time.toString(), time.toNanos()));
-                /* For each series, get the value at the index */
-                for (IXYSeries serie : series) {
-                    double[] yS = serie.getYSeries();
-                    /* Make sure the series values and the value at index exist */
-                    if (isValid(index, serie)) {
-                        String key = serie.getId();
-                        Color color = serie.getColor();
-                        if (key != null && color != null && viewer != null) {
-                            RGBA rgba = color.getRGBA();
-                            RGBAColor rgbaColor = new RGBAColor(rgba.rgb.red, rgba.rgb.green, rgba.rgb.blue, rgba.alpha);
-                            key = String.format(HTML_COLOR_TOOLTIP, rgbaColor, key);
-                        }
-                        if (key == null) {
-                            key = ""; //$NON-NLS-1$
-                        }
-                        double yValue = yS[index];
-                        if (format == null) {
-                            addItem(null, ToolTipString.fromHtml(key), ToolTipString.fromDecimal(yValue));
-                        } else {
-                            addItem(null, ToolTipString.fromHtml(key), ToolTipString.fromString(format.format(yValue)));
-                        }
-                    }
-                }
-            }
-        }
-
-    }
-
-    private XYToolTipHandler fToolTipHandler = new XYToolTipHandler();
+    private static final String HTML_COLOR_TOOLTIP = "<span style=\"color:%s;\">%s</span>"; //$NON-NLS-1$
+    private final CommonToolTipHandler fToolTipHandler = new CommonToolTipHandler();
 
     /**
      * Constructor for the tooltip provider
@@ -142,4 +69,98 @@ public TmfAbstractToolTipHandler getTooltipHandler() {
     public void refresh() {
         // nothing to do
     }
+
+    protected boolean isTooltipAvailable() {
+        return getChartViewer().getWindowDuration() != 0;
+    }
+
+    protected int getHoveredIndex(List<IXYSeries> series, double xCoordinate) {
+        if (series.isEmpty()) {
+            return -1;
+        }
+        double[] xSeries = series.get(0).getXSeries();
+        if ((xSeries == null) || (xSeries.length == 0)) {
+            return -1;
+        }
+        int index = Arrays.binarySearch(xSeries, xCoordinate);
+        index = (index >= 0) ? index : -index - 1;
+        return (index < xSeries.length) ? index : -1;
+    }
+
+    protected boolean isValidSeriesIndex(IXYSeries series, int index) {
+        double[] ySeries = series.getYSeries();
+        return series.isVisible() && ySeries != null && index >= 0 && index < ySeries.length;
+    }
+
+    protected void addAdditionalTooltipItems(double xCoordinate, String seriesKey) {
+        // Default: no-op
+    }
+
+    protected void addSeriesTooltipItem(IXYSeries series, String key, int index, Format format) {
+        double[] ySeries = series.getYSeries();
+        if (ySeries == null || index < 0 || index >= ySeries.length) {
+            return;
+        }
+
+        String label = formatSeriesLabel(series, key);
+        double yValue = ySeries[index];
+        if (format == null) {
+            addItem(null, ToolTipString.fromHtml(label), ToolTipString.fromDecimal(yValue));
+        } else {
+            addItem(null, ToolTipString.fromHtml(label), ToolTipString.fromString(format.format(yValue)));
+        }
+    }
+
+    protected String formatSeriesLabel(IXYSeries series, String key) {
+        String label = (key == null) ? "" : key; //$NON-NLS-1$
+        Color color = series.getColor();
+        if (color != null) {
+            RGBA rgba = color.getRGBA();
+            RGBAColor rgbaColor = new RGBAColor(rgba.rgb.red, rgba.rgb.green, rgba.rgb.blue, rgba.alpha);
+            label = String.format(TmfCommonXLineChartTooltipProvider.HTML_COLOR_TOOLTIP, rgbaColor, label);
+        }
+        return label;
+    }
+
+    private final class CommonToolTipHandler extends TmfAbstractToolTipHandler {
+
+        @Override
+        public void fill(Control control, MouseEvent event, Point pt) {
+            if (!isTooltipAvailable()) {
+                return;
+            }
+
+            IAxis xAxis = getXAxis();
+            double xCoordinate = xAxis.getDataCoordinate(pt.x);
+            if (xCoordinate < 0) {
+                return;
+            }
+
+            List<IXYSeries> series = getSeries();
+            int index = getHoveredIndex(series, xCoordinate);
+            if (index < 0) {
+                return;
+            }
+
+            Format format = null;
+            if (getChartViewer() instanceof TmfCommonXAxisChartViewer chartViewer) {
+                format = chartViewer.getSwtChart().getAxisSet().getYAxes()[0].getTick().getFormat();
+            }
+
+            boolean additionalItemsAdded = false;
+            for (IXYSeries xySeries : series) {
+                if (!isValidSeriesIndex(xySeries, index)) {
+                    continue;
+                }
+
+                String key = xySeries.getId();
+                if (!additionalItemsAdded) {
+                    addAdditionalTooltipItems(xCoordinate, key);
+                    additionalItemsAdded = true;
+                }
+
+                addSeriesTooltipItem(xySeries, key, index, format);
+            }
+        }
+    }
 }