ParagraphText: immediately remove listeners from SelectionPath and Caret on dispose instead of waiting for GC (this improves PR FXMisc#779, issue FXMisc#627)

without this change, disposed ParagraphText objects still listen to selection and caret and do some useless stuff

Author: DevCharly

richtextfx/src/main/java/org/fxmisc/richtext/GenericStyledArea.java

@@ -1463,6 +1463,7 @@ public void dispose() {
                 box.wrapTextProperty().unbind();
                 box.graphicFactoryProperty().unbind();
                 box.graphicOffset.unbind();
+                box.dispose();
 
                 firstParPseudoClass.unsubscribe();
                 lastParPseudoClass.unsubscribe();

richtextfx/src/main/java/org/fxmisc/richtext/ParagraphBox.java

@@ -22,7 +22,6 @@
 import javafx.geometry.Insets;
 import javafx.geometry.Point2D;
 import javafx.scene.Node;
-import javafx.scene.control.IndexRange;
 import javafx.scene.layout.Region;
 import javafx.scene.paint.Paint;
 import javafx.scene.text.TextFlow;
@@ -118,6 +117,10 @@ public final ObservableMap<Selection<PS, SEG, S>, SelectionPath> selectionsPrope
         graphicOffset.addListener(obs -> requestLayout());
     }
 
+    void dispose() {
+        text.dispose();
+    }
+
     @Override
     public String toString() {
         return String.format(

richtextfx/src/main/java/org/fxmisc/richtext/ParagraphText.java

@@ -62,6 +62,9 @@ class ParagraphText<PS, SEG, S> extends TextFlowExt {
             FXCollections.observableMap(new HashMap<>(1));
     public final ObservableMap<Selection<PS, SEG, S>, SelectionPath> selectionsProperty() { return selections; }
 
+    private final ChangeListener<IndexRange> selectionRangeListener;
+    private final ChangeListener<Integer> caretPositionListener;
+
     // FIXME: changing it currently has not effect, because
     // Text.impl_selectionFillProperty().set(newFill) doesn't work
     // properly for Text node inside a TextFlow (as of JDK8-b100).
@@ -95,11 +98,11 @@ public ObjectProperty<Paint> highlightTextFillProperty() {
         Val<Double> leftInset = Val.map(insetsProperty(), Insets::getLeft);
         Val<Double> topInset = Val.map(insetsProperty(), Insets::getTop);
 
-        ChangeListener<IndexRange> requestLayout1 = new SelectionRangeChangeListener<>(this);
-        selections.addListener(new SelectionsSetListener<>(leftInset, requestLayout1, topInset, this));
+        selectionRangeListener = new SelectionRangeChangeListener<>(this);
+        selections.addListener(new SelectionsSetListener<>(leftInset, selectionRangeListener, topInset, this));
 
-        ChangeListener<Integer> requestLayout2 = new CaretPositionChangeListener<>(this);
-        carets.addListener(new CaretsChangeListener<>(leftInset, requestLayout2, topInset, this));
+        caretPositionListener = new CaretPositionChangeListener<>(this);
+        carets.addListener(new CaretsChangeListener<>(leftInset, caretPositionListener, topInset, this));
 
         // XXX: see the note at highlightTextFill
 //        highlightTextFill.addListener(new ChangeListener<Paint>() {
@@ -182,6 +185,20 @@ public ObjectProperty<Paint> highlightTextFillProperty() {
         );
     }
 
+    void dispose() {
+        for (SelectionPath p : selections.values()) {
+            p.rangeProperty().removeListener(selectionRangeListener);
+            p.layoutXProperty().unbind();
+            p.layoutYProperty().unbind();
+        }
+
+        for (CaretNode caret : carets) {
+            caret.columnPositionProperty().removeListener(caretPositionListener);
+            caret.layoutXProperty().unbind();
+            caret.layoutYProperty().unbind();
+        }
+    }
+
     public Paragraph<PS, SEG, S> getParagraph() {
         return paragraph;
     }