application/org.openjdk.jmc.ui/src/main/java/org/openjdk/jmc/ui/charts/IChartInfoVisitor.java

@@ -38,11 +38,11 @@
 
 import org.openjdk.jmc.common.IDisplayable;
 
 /**
  * Visitor interface to gather information about values displayed in charts, typically in the
- * vicinity of some coordinates. Suitable for tooltips, highlighting or snapping.
+ * vicinity of some coordinates. Suitable for tooltips, highlighting, hovering or snapping.
  */
 public interface IChartInfoVisitor {
         public abstract class Adapter implements IChartInfoVisitor {
 
                 @Override

@@ -53,10 +53,14 @@
                 @Override
                 public void leaveScope() {
                 }
 
                 @Override
+                public void hover(Object data) {
+                }
+
+                @Override
                 public void visit(IBucket bucket) {
                 }
 
                 @Override
                 public void visit(IPoint point) {

@@ -172,10 +176,20 @@
         boolean enterScope(String context, boolean fullyShown);
 
         void leaveScope();
 
         /**
+         * Deliver supplementary information about the hovered rendered item to the Visitor.
+         * <p>
+         * To be used in conjunction with an rendered item's {@code infoAt()} to
+         * deliver supplementary information about the currently hovered object to the Visitor.
+         *
+         * @param data
+         */
+        void hover(Object data);
+
+        /**
          * Visit a bucket in a histogram.
          * <p>
          * Note that the provided {@link IBucket} instance may be reused and thus cannot be directly
          * saved by the visitor. Visitors wishing to delay processing of {@link IBucket}s, can do so by
          * requesting an instance that will remain valid at least until the chart changes state, through