Xy data set refactor (#97)

* Renamed max() to maxOfY(), changed return type to OptionalDouble, better tests

* Moved XYDataSet into samples module

* Reformatted XML to avoid hurting Martijn's eyes

core/api/src/main/java/module-info.java

@@ -44,7 +44,6 @@ module com.microsoft.gctoolkit.api {
     exports com.microsoft.gctoolkit.io;
     exports com.microsoft.gctoolkit.jvm;
     exports com.microsoft.gctoolkit.time;
-    exports com.microsoft.gctoolkit.collections;
     exports com.microsoft.gctoolkit.util.concurrent;
     requires java.logging;
 

sample/pom.xml

@@ -25,6 +25,14 @@
             <artifactId>gctoolkit-vertx</artifactId>
             <version>${project.version}</version>
         </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-engine</artifactId>
+        </dependency>
     </dependencies>
 
     <build>

sample/src/main/java/com/microsoft/gctoolkit/sample/aggregation/HeapOccupancyAfterCollectionSummary.java

@@ -1,7 +1,7 @@
 package com.microsoft.gctoolkit.sample.aggregation;
 
 import com.microsoft.gctoolkit.aggregator.Collates;
-import com.microsoft.gctoolkit.collections.XYDataSet;
+import com.microsoft.gctoolkit.sample.collections.XYDataSet;
 import com.microsoft.gctoolkit.event.GarbageCollectionTypes;
 import com.microsoft.gctoolkit.time.DateTimeStamp;
 

sample/src/main/java/com/microsoft/gctoolkit/sample/collections/XYDataSet.java

@@ -1,16 +1,14 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
-package com.microsoft.gctoolkit.collections;
+package com.microsoft.gctoolkit.sample.collections;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.OptionalDouble;
 import java.util.stream.Stream;
 
-import static java.util.Collections.unmodifiableList;
-
 public class XYDataSet {
-
-    private List<Point> dataSeries;
+    private final List<Point> dataSeries;
 
     public XYDataSet() {
         dataSeries = new ArrayList<>();
@@ -18,7 +16,6 @@ public class XYDataSet {
 
     public XYDataSet(XYDataSet series) {
         dataSeries = new ArrayList<>(series.getItems());
-
     }
 
     public void add(Number x, Number y) {
@@ -37,8 +34,11 @@ public class XYDataSet {
         return dataSeries.isEmpty();
     }
 
+    /**
+     * Returns an immutable List of the items in this DataSet.
+     */
     public List<Point> getItems() {
-        return unmodifiableList(dataSeries);
+        return List.copyOf(dataSeries);
     }
 
     public XYDataSet scaleSeries(double scaleFactor) {
@@ -49,8 +49,15 @@ public class XYDataSet {
         return scaled;
     }
 
-    public double max() {
-        return dataSeries.stream().map(Point::getY).mapToDouble(Number::doubleValue).max().getAsDouble();
+    /**
+     * Returns the largest Y value in the XYDataSet as an OptionalDouble,
+     * with an empty optional if the dataset is empty.
+     */
+    public OptionalDouble maxOfY() {
+        return dataSeries.stream()
+                .map(Point::getY)
+                .mapToDouble(Number::doubleValue)
+                .max();
     }
 
     public XYDataSet scaleAndTranslateXAxis(double scale, double offset) {
@@ -71,7 +78,6 @@ public class XYDataSet {
     }
 
     public static class Point {
-
         private final Number x;
         private final Number y;
 
@@ -83,6 +89,7 @@ public class XYDataSet {
         public Number getX() {
             return x;
         }
+
         public Number getY() {
             return y;
         }

sample/src/main/java/module-info.java

@@ -8,12 +8,12 @@ import com.microsoft.gctoolkit.sample.aggregation.HeapOccupancyAfterCollectionSu
  * Contains an Aggregator and an Aggregation
  */
 module com.microsoft.gctoolkit.sample {
-
     requires com.microsoft.gctoolkit.api;
     requires com.microsoft.gctoolkit.vertx;
     requires java.logging;
 
     exports com.microsoft.gctoolkit.sample.aggregation to com.microsoft.gctoolkit.vertx;
+    exports com.microsoft.gctoolkit.sample.collections to gctoolkit.sample.test;
 
     provides Aggregation with HeapOccupancyAfterCollectionSummary;
 }

sample/src/test/java/com/microsoft/gctoolkit/sample/test/collections/XYDataSetTest.java

@@ -1,40 +1,46 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
-package com.microsoft.gctoolkit.test.collections;
+package com.microsoft.gctoolkit.sample.test.collections;
 
-import com.microsoft.gctoolkit.collections.XYDataSet;
-import com.microsoft.gctoolkit.collections.XYDataSet.Point;
+import com.microsoft.gctoolkit.sample.collections.XYDataSet;
+import com.microsoft.gctoolkit.sample.collections.XYDataSet.Point;
 import org.junit.jupiter.api.Test;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class XYDataSetTest {
-
     @Test
     void shouldScaleOnlyY_AxisDataSet() {
-        XYDataSet xyDataSet = new XYDataSet();
+        var xyDataSet = new XYDataSet();
         xyDataSet.add(new Point(50, 100));
         XYDataSet scaledPoint = xyDataSet.scaleSeries(2);
         assertEquals(50, scaledPoint.getItems().get(0).getX());
         assertEquals(200.0, scaledPoint.getItems().get(0).getY());
     }
 
-
     @Test
     void shouldReturnMaximumValueOfY_Axis() {
-        XYDataSet xyDataSet = new XYDataSet();
+        var xyDataSet = new XYDataSet();
         xyDataSet.add(new Point(50, 100));
         xyDataSet.add(new Point(100, 140));
         xyDataSet.add(new Point(75, 230));
-        assertEquals(230, xyDataSet.max());
+        // added a bigger X than Y value
+        xyDataSet.add(new Point(1075, 10));
+        assertEquals(230, xyDataSet.maxOfY().getAsDouble());
     }
 
     @Test
     void shouldReturnScaledAndTranslatedX_AxisDataSet() {
-        XYDataSet xyDataSet = new XYDataSet();
+        var xyDataSet = new XYDataSet();
         xyDataSet.add(new Point(50, 100));
-        XYDataSet translated = xyDataSet.scaleAndTranslateXAxis(2, 20);
+        var translated = xyDataSet.scaleAndTranslateXAxis(2, 20);
         assertEquals(120.0, translated.getItems().get(0).getX());
         assertEquals(100, translated.getItems().get(0).getY());
     }
-}
+
+    @Test
+    void maxOnEmptyDataSet() {
+        assertTrue(new XYDataSet().maxOfY().isEmpty());
+    }
+}

sample/src/test/java/module-info.java

@@ -0,0 +1,8 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+open module gctoolkit.sample.test {
+    requires com.microsoft.gctoolkit.sample;
+    requires java.logging;
+    requires org.junit.jupiter.api;
+    requires org.junit.jupiter.engine;
+}