made it more convenient to get to the style nodes

chartfx-chart/src/main/java/io/fair_acc/chartfx/Chart.java

@@ -5,7 +5,6 @@
 import java.util.function.Consumer;
 import java.util.stream.Collectors;
 
-import io.fair_acc.chartfx.renderer.spi.AbstractRenderer;
 import io.fair_acc.chartfx.renderer.spi.ErrorDataSetRenderer;
 import io.fair_acc.chartfx.ui.css.ColorPalette;
 import io.fair_acc.chartfx.ui.css.StyleGroup;
@@ -220,7 +219,6 @@ public Chart(Axis... axes) {
         // Setup listeners
         showing.bind(FXUtils.getShowingBinding(this));
         getRenderers().addListener(rendererChangeListener);
-        getDatasets().addListener(datasetChangeListener);
         getPlugins().addListener(pluginsChangedListener);
         getAxes().addListener(axesChangeListenerLocal);
         getAxes().addListener(axesChangeListener);
@@ -284,6 +282,9 @@ public Chart(Axis... axes) {
         menuPane.setContent(measurementPane);
         getChildren().add(menuPane);
 
+        // TODO: get rid of default instance. It's created if anyone wants to use getDatasets()
+        getRenderers().add(new ErrorDataSetRenderer());
+
     }
 
     @Override
@@ -310,17 +311,16 @@ public final BooleanProperty animatedProperty() {
     }
 
     /**
-     * @return datasets attached to the chart and datasets attached to all renderers
+     * @return datasets attached to all renderers
      */
     public ObservableList<DataSet> getAllDatasets() {
-        if (getRenderers() == null) {
-            return allDataSets;
-        }
-
         allDataSets.clear();
-        allDataSets.addAll(getDatasets());
-        getRenderers().stream().filter(renderer -> !(renderer instanceof LabelledMarkerRenderer)).forEach(renderer -> allDataSets.addAll(renderer.getDatasets()));
-
+        for (Renderer renderer : renderers) {
+            if (renderer instanceof LabelledMarkerRenderer) {
+                continue;
+            }
+            allDataSets.addAll(renderer.getDatasets());
+        }
         return allDataSets;
     }
 
@@ -343,16 +343,6 @@ public final Pane getCanvasForeground() {
         return canvasForeground;
     }
 
-    /**
-     * @return datasets of the first renderer. Creates a renderer if needed.
-     */
-    public ObservableList<DataSet> getDatasets() {
-        if (getRenderers().isEmpty()) {
-            getRenderers().add(new ErrorDataSetRenderer());
-        }
-        return getRenderers().get(0).getDatasets();
-    }
-
     public Axis getFirstAxis(final Orientation orientation) {
         for (final Axis axis : getAxes()) {
             if (axis.getSide() == null) {
@@ -513,7 +503,7 @@ protected void runPreLayout() {
 
         // Update legend
         if (state.isDirty(ChartBits.ChartLegend)) {
-            updateLegend(getDatasets(), getRenderers());
+            updateLegend(getRenderers());
         }
         state.clear(ChartBits.ChartLegend);
 
@@ -661,7 +651,7 @@ private void updateStandaloneRendererAxes() {
         }
     }
 
-    private void forEachDataSet(Consumer<DataSet> action) {
+    protected void forEachDataSet(Consumer<DataSet> action) {
         for (Renderer renderer : renderers) {
             for (DataSet dataset : renderer.getDatasets()) {
                 action.accept(dataset);
@@ -897,12 +887,10 @@ protected void rendererChanged(final ListChangeListener.Change<? extends Rendere
                     dataset.addListener(dataSetState);
                 }
                 renderer.getDatasets().addListener(datasetChangeListener);
-                if (renderer instanceof AbstractRenderer) {
-                    var node = (AbstractRenderer<?>) renderer;
-                    node.setChart(this);
-                    if (!styleableNodes.getChildren().contains(node)) {
-                        styleableNodes.getChildren().add(node);
-                    }
+                renderer.setChart(this);
+                var node = renderer.getNode();
+                if (node != null && !styleableNodes.getChildren().contains(node)) {
+                    styleableNodes.getChildren().add(node);
                 }
             }
 
@@ -912,11 +900,8 @@ protected void rendererChanged(final ListChangeListener.Change<? extends Rendere
                     dataset.removeListener(dataSetState);
                 }
                 renderer.getDatasets().removeListener(datasetChangeListener);
-                if (renderer instanceof AbstractRenderer) {
-                    var node = (AbstractRenderer<?>) renderer;
-                    styleableNodes.getChildren().remove(node);
-                    node.setChart(null);
-                }
+                styleableNodes.getChildren().remove(renderer.getNode());
+                renderer.setChart(null);
             }
 
         }
@@ -939,7 +924,7 @@ protected final boolean shouldAnimate() {
         return isAnimated() && getScene() != null;
     }
 
-    protected void updateLegend(final List<DataSet> dataSets, final List<Renderer> renderers) {
+    protected void updateLegend(final List<Renderer> renderers) {
         final Legend legend = getLegend();
         if (legend == null) {
             return;

chartfx-chart/src/main/java/io/fair_acc/chartfx/XYChart.java

@@ -6,6 +6,7 @@
 import java.util.stream.Collectors;
 
 import io.fair_acc.chartfx.axes.spi.AxisRange;
+import io.fair_acc.chartfx.renderer.spi.ErrorDataSetRenderer;
 import io.fair_acc.chartfx.ui.css.DataSetNode;
 import io.fair_acc.chartfx.utils.PropUtil;
 import io.fair_acc.dataset.events.ChartBits;
@@ -97,6 +98,16 @@ public XYChart(final Axis... axes) {
         getRenderers().addListener(this::rendererChanged);
     }
 
+    /**
+     * @return datasets of the first renderer. Creates a renderer if needed.
+     */
+    public ObservableList<DataSet> getDatasets() {
+        if (getRenderers().isEmpty()) {
+            getRenderers().add(new ErrorDataSetRenderer());
+        }
+        return getRenderers().get(0).getDatasets();
+    }
+
     /**
      * @return datasets attached to the chart and datasets attached to all renderers
      */
@@ -122,7 +133,6 @@ public ObservableList<DataSet> getAllDatasets() {
      */
     public ObservableList<DataSet> getAllShownDatasets() {
         final ObservableList<DataSet> ret = FXCollections.observableArrayList();
-        ret.addAll(getDatasets());
         getRenderers().stream().filter(Renderer::showInLegend).forEach(renderer -> ret.addAll(renderer.getDatasets()));
         return ret;
     }
@@ -195,10 +205,6 @@ public void setPolarStepSize(final PolarTickStep step) {
 
     @Override
     public void updateAxisRange() {
-        if (isDataEmpty()) {
-            return;
-        }
-
         // Check that all registered data sets have proper ranges defined. The datasets
         // are already locked, so we can use parallel stream without extra synchronization.
         getRenderers().stream()
@@ -213,11 +219,6 @@ public void updateAxisRange() {
 
         // Update each of the axes
         getAxes().forEach(chartAxis -> updateNumericAxis(chartAxis, getDataSetForAxis(chartAxis)));
-
-    }
-
-    private boolean isDataEmpty() {
-        return getAllDatasets() == null || getAllDatasets().isEmpty();
     }
 
     /**
@@ -366,4 +367,5 @@ protected static void updateNumericAxis(final Axis axis, final List<DataSetNode>
         }
 
     }
+
 }

chartfx-chart/src/main/java/io/fair_acc/chartfx/plugins/UpdateAxisLabels.java

@@ -4,6 +4,7 @@
 import java.util.Map;
 import java.util.Optional;
 
+import io.fair_acc.chartfx.XYChart;
 import io.fair_acc.dataset.events.ChartBits;
 import io.fair_acc.dataset.events.StateListener;
 import javafx.beans.value.ChangeListener;
@@ -27,6 +28,7 @@
  * updated, if there is exactly one DataSet in the each Renderer or the Chart.
  *
  * TODO: revisit this plugin. we should be able to turn this into a single chart listener and an update method (ennerf)
+ * TODO: this is using Chart::getDataSets() which doesn't really exist anymore
  *
  * @author akrimm
  */
@@ -69,8 +71,8 @@ public class UpdateAxisLabels extends ChartPlugin {
 
     // called whenever the chart for the plugin is changed
     private final ChangeListener<? super Chart> chartChangeListener = (change, oldChart, newChart) -> {
-        removeRendererAndDataSetListener(oldChart);
-        addRendererAndDataSetListener(newChart);
+        removeRendererAndDataSetListener((XYChart) oldChart);
+        addRendererAndDataSetListener((XYChart) newChart);
     };
 
     /**
@@ -79,10 +81,10 @@ public class UpdateAxisLabels extends ChartPlugin {
     public UpdateAxisLabels() {
         super();
         chartProperty().addListener(chartChangeListener);
-        addRendererAndDataSetListener(getChart());
+        addRendererAndDataSetListener(getXYChart());
     }
 
-    private void addRendererAndDataSetListener(Chart newChart) {
+    private void addRendererAndDataSetListener(XYChart newChart) {
         if (newChart == null) {
             return;
         }
@@ -91,10 +93,14 @@ private void addRendererAndDataSetListener(Chart newChart) {
         newChart.getRenderers().forEach((Renderer r) -> setupDataSetListeners(r, r.getDatasets()));
     }
 
+    private XYChart getXYChart() {
+        return (XYChart) super.getChart();
+    }
+
     // the actual DataSet renaming logic
     private void dataSetChange(DataSet dataSet, Renderer renderer) {
         if (renderer == null) { // dataset was added to / is registered at chart
-            if (getChart().getDatasets().size() == 1) {
+            if (getXYChart().getDatasets().size() == 1) {
                 for (int dimIdx = 0; dimIdx < dataSet.getDimension(); dimIdx++) {
                     final int dimIndex = dimIdx;
                     Optional<Axis> oldAxis = getChart().getAxes().stream().filter(axis -> axis.getDimIndex() == dimIndex).findFirst();
@@ -156,7 +162,7 @@ private void dataSetsChanged(ListChangeListener.Change<? extends DataSet> change
         }
     }
 
-    private void removeRendererAndDataSetListener(Chart oldChart) {
+    private void removeRendererAndDataSetListener(XYChart oldChart) {
         if (oldChart == null) {
             return;
         }

chartfx-chart/src/main/java/io/fair_acc/chartfx/renderer/Renderer.java

@@ -1,13 +1,18 @@
 package io.fair_acc.chartfx.renderer;
 
+import io.fair_acc.chartfx.Chart;
 import io.fair_acc.chartfx.ui.css.DataSetNode;
 import javafx.beans.property.BooleanProperty;
 import javafx.collections.ObservableList;
+import javafx.scene.Node;
 import javafx.scene.canvas.Canvas;
 
 import io.fair_acc.chartfx.axes.Axis;
 import io.fair_acc.dataset.DataSet;
 
+import java.util.ArrayList;
+import java.util.List;
+
 /**
  * -- generic renderer interface --
  *
@@ -35,6 +40,28 @@ default boolean drawLegendSymbol(DataSetNode dataSet, Canvas canvas) {
 
     ObservableList<DataSetNode> getDatasetNodes();
 
+    default DataSetNode getStyleableNode(DataSet dataSet) {
+        for (DataSetNode datasetNode : getDatasetNodes()) {
+            if (datasetNode.getDataSet() == dataSet) {
+                return datasetNode;
+            }
+        }
+        throw new IllegalArgumentException("dataset does not have a styleable node");
+    }
+
+    default DataSetNode addDataSet(DataSet dataSet) {
+        getDatasets().add(dataSet);
+        return getStyleableNode(dataSet);
+    }
+
+    default List<DataSetNode> addDataSets(DataSet... dataSets) {
+        List<DataSetNode> retVal = new ArrayList<>(dataSets.length);
+        for (DataSet dataSet : dataSets) {
+            retVal.add(addDataSet(dataSet));
+        }
+        return retVal;
+    }
+
     /**
      * Optional method that allows the renderer make layout changes after axes and dataset limits are known.
      * Gets called after axis ranges are known
@@ -93,4 +120,13 @@ default boolean isUsingAxis(Axis axis) {
     void setGlobalIndexOffset(int value);
     int getGlobalIndexOffset();
 
+    default void setChart(Chart chart) {
+        // do nothing if it's not needed
+    }
+
+    default Node getNode() {
+        // add nothing if not needed
+        return null;
+    }
+
 }

chartfx-chart/src/main/java/io/fair_acc/chartfx/renderer/spi/AbstractRenderer.java

@@ -22,6 +22,7 @@
 import javafx.css.Styleable;
 import javafx.css.StyleableBooleanProperty;
 import javafx.geometry.Orientation;
+import javafx.scene.Node;
 import javafx.scene.Parent;
 
 import java.util.List;
@@ -48,7 +49,7 @@ public abstract class AbstractRenderer<R extends Renderer> extends Parent implem
     protected DataSetNode createNode(DataSet dataSet) {
         // Reuse existing nodes when possible
         for (DataSetNode dataSetNode : dataSetNodes) {
-            if (dataSetNode.getDataSet() == dataSet) {
+            if(dataSetNode.getDataSet() == dataSet) {
                 return dataSetNode;
             }
         }
@@ -278,6 +279,11 @@ protected void fireInvalidated(IntSupplier bit) {
         }
     }
 
+    @Override
+    public Node getNode() {
+        return this;
+    }
+
     protected CssPropertyFactory<AbstractRenderer<?>> css() {
         return CSS; // subclass specific CSS due to inheritance issues otherwise
     }

chartfx-samples/src/main/java/io/fair_acc/sample/chart/ChartAnatomySample.java

@@ -73,7 +73,7 @@ public void updateAxisRange() {
             }
 
             @Override
-            protected void updateLegend(final List<DataSet> dataSets, final List<Renderer> renderers) {
+            protected void updateLegend(final List<Renderer> renderers) {
                 // TODO Auto-generated method stub
             }
         };

chartfx-samples/src/main/java/io/fair_acc/sample/chart/ZoomerSample.java

@@ -112,7 +112,7 @@ private static DataSet generateData() {
     }
 
     private static Chart getTestChart(final String title, final DataSet testDataSet) {
-        final Chart chart = new XYChart();
+        final var chart = new XYChart();
         chart.setTitle(title);
         chart.setLegendVisible(false);
         chart.getDatasets().add(testDataSet);