Refactor Code to Address Implementation and Design Smells

xchart-demo/src/main/java/org/knowm/xchart/demo/DemoChartsUtil.java

@@ -4,8 +4,6 @@
 import java.io.IOException;
 import java.net.URL;
 import java.util.ArrayList;
-import java.util.Collections;
-import java.util.Comparator;
 import java.util.Enumeration;
 import java.util.List;
 import java.util.jar.JarEntry;
@@ -20,77 +18,26 @@ public class DemoChartsUtil {
   private static final String DEMO_CHARTS_PACKAGE = "org.knowm.xchart.demo.charts";
 
   public static List<ExampleChart<Chart<Styler, Series>>> getAllDemoCharts() {
-
+    
     List<ExampleChart<Chart<Styler, Series>>> demoCharts = null;
     String packagePath = DEMO_CHARTS_PACKAGE.replace(".", "/");
     ClassLoader loader = Thread.currentThread().getContextClassLoader();
     URL url = loader.getResource(packagePath);
-
     if (url != null) {
       try {
-        demoCharts = getAllDemoCharts(url);
+        demoCharts = URLClassUtil.getAllDemoCharts(url);
       } catch (Exception e) {
         e.printStackTrace();
       }
     }
-
-    return demoCharts;
-  }
-
-  @SuppressWarnings("unchecked")
-  private static List<ExampleChart<Chart<Styler, Series>>> getAllDemoCharts(URL url)
-      throws Exception {
-
-    List<ExampleChart<Chart<Styler, Series>>> demoCharts = new ArrayList<>();
-
-    List<Class<?>> classes = getAllAssignedClasses(url);
-    // sort
-    Collections.sort(
-        classes,
-        new Comparator<Class<?>>() {
-
-          @Override
-          public int compare(Class<?> c1, Class<?> c2) {
-            return c1.getName().compareTo(c2.getName());
-          }
-        });
-
-    for (Class<?> c : classes) {
-      demoCharts.add(((ExampleChart<Chart<Styler, Series>>) c.newInstance()));
-    }
     return demoCharts;
   }
 
-  private static List<Class<?>> getAllAssignedClasses(URL url)
-      throws ClassNotFoundException, IOException {
-
-    List<Class<?>> classes = null;
-
-    String type = url.getProtocol();
-    if ("file".equals(type)) {
-      classes = getClassesByFile(new File(url.getFile()), DEMO_CHARTS_PACKAGE);
-    } else if ("jar".equals(type)) {
-      classes = getClassesByJar(url.getPath());
-    }
-    List<Class<?>> allAssignedClasses = new ArrayList<>();
-    if (classes != null) {
-      for (Class<?> c : classes) {
-        if (ExampleChart.class.isAssignableFrom(c) && !ExampleChart.class.equals(c)) {
-          allAssignedClasses.add(c);
-        }
-      }
-    }
-    return allAssignedClasses;
-  }
-
-  private static List<Class<?>> getClassesByFile(File dir, String pk)
-      throws ClassNotFoundException {
-
+  public static List<Class<?>> getClassesByFile(File dir, String pk) throws ClassNotFoundException {
     List<Class<?>> classes = new ArrayList<>();
     if (!dir.exists()) {
       return classes;
     }
-
     String fileName = "";
     for (File f : dir.listFiles()) {
       fileName = f.getName();
@@ -101,14 +48,12 @@ private static List<Class<?>> getClassesByFile(File dir, String pk)
             Class.forName(pk + "." + fileName.substring(0, fileName.length() - ".class".length())));
       }
     }
-
     return classes;
   }
 
   @SuppressWarnings("resource")
-  private static List<Class<?>> getClassesByJar(String jarPath)
+  public static List<Class<?>> getClassesByJar(String jarPath)
       throws IOException, ClassNotFoundException {
-
     List<Class<?>> classes = new ArrayList<>();
     String[] jarInfo = jarPath.split("!");
     String jarFilePath = jarInfo[0].substring(jarInfo[0].indexOf("/"));

xchart-demo/src/main/java/org/knowm/xchart/demo/URLClassUtil.java

@@ -0,0 +1,58 @@
+package org.knowm.xchart.demo;
+
+import java.io.File;
+import java.io.IOException;
+import java.net.URL;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+import org.knowm.xchart.demo.charts.ExampleChart;
+import org.knowm.xchart.internal.chartpart.Chart;
+import org.knowm.xchart.internal.series.Series;
+import org.knowm.xchart.style.Styler;
+
+public class URLClassUtil {
+
+  private static final String DEMO_CHARTS_PACKAGE = "org.knowm.xchart.demo.charts";
+
+  @SuppressWarnings("unchecked")
+  public static List<ExampleChart<Chart<Styler, Series>>> getAllDemoCharts(URL url)
+      throws Exception {
+    List<ExampleChart<Chart<Styler, Series>>> demoCharts = new ArrayList<>();
+    List<Class<?>> classes = getAllAssignedClasses(url);
+    // sort
+    Collections.sort(
+        classes,
+        new Comparator<Class<?>>() {
+          @Override
+          public int compare(Class<?> c1, Class<?> c2) {
+            return c1.getName().compareTo(c2.getName());
+          }
+        });
+    for (Class<?> c : classes) {
+      demoCharts.add(((ExampleChart<Chart<Styler, Series>>) c.newInstance()));
+    }
+    return demoCharts;
+  }
+
+  public static List<Class<?>> getAllAssignedClasses(URL url)
+      throws ClassNotFoundException, IOException {
+    List<Class<?>> classes = null;
+    String type = url.getProtocol();
+    if ("file".equals(type)) {
+      classes = DemoChartsUtil.getClassesByFile(new File(url.getFile()), DEMO_CHARTS_PACKAGE);
+    } else if ("jar".equals(type)) {
+      classes = DemoChartsUtil.getClassesByJar(url.getPath());
+    }
+    List<Class<?>> allAssignedClasses = new ArrayList<>();
+    if (classes != null) {
+      for (Class<?> c : classes) {
+        if (ExampleChart.class.isAssignableFrom(c) && !ExampleChart.class.equals(c)) {
+          allAssignedClasses.add(c);
+        }
+      }
+    }
+    return allAssignedClasses;
+  }
+}

xchart/src/main/java/org/knowm/xchart/CategoryChart.java

@@ -59,19 +59,6 @@ public CategoryChart(int width, int height, ChartTheme chartTheme) {
     this(width, height, chartTheme.newInstance(chartTheme));
   }
 
-  /**
-   * Constructor
-   *
-   * @param chartBuilder
-   */
-  public CategoryChart(CategoryChartBuilder chartBuilder) {
-
-    this(chartBuilder.width, chartBuilder.height, chartBuilder.chartTheme);
-    setTitle(chartBuilder.title);
-    setXAxisTitle(chartBuilder.xAxisTitle);
-    setYAxisTitle(chartBuilder.yAxisTitle);
-  }
-
   /**
    * Add a series for a Category type chart using using double arrays
    *

xchart/src/main/java/org/knowm/xchart/CategoryChartBuilder.java

@@ -28,7 +28,11 @@ public CategoryChartBuilder yAxisTitle(String yAxisTitle) {
    */
   @Override
   public CategoryChart build() {
-
-    return new CategoryChart(this);
+    // Pass the configured properties to CategoryChart during creation
+    CategoryChart chart = new CategoryChart(this.width, this.height, this.chartTheme);
+    chart.setTitle(this.title);
+    chart.setXAxisTitle(this.xAxisTitle);
+    chart.setYAxisTitle(this.yAxisTitle);
+    return chart;
   }
 }

xchart/src/main/java/org/knowm/xchart/internal/chartpart/Axis.java

@@ -753,7 +753,10 @@ public double getChartValue(double screenPoint) {
 
     minVal = isLog ? Math.log10(minVal) : minVal;
     maxVal = isLog ? Math.log10(maxVal) : maxVal;
-    double value = ((screenPoint - margin - startOffset) * (maxVal - minVal) / tickSpace) + minVal;
+    double adjustedScreenPoint = screenPoint - margin - startOffset;
+    double valueRange = maxVal - minVal;
+    double normalizedValue = (adjustedScreenPoint * valueRange) / tickSpace;
+    double value = normalizedValue + minVal;
     value = isLog ? Math.pow(10, value) : value;
     return value;
   }

xchart/src/main/java/org/knowm/xchart/internal/chartpart/AxisPair.java

@@ -331,25 +331,12 @@ private void prepareForPaint() {
       }
     }
     // infinity checks
-    if (xAxis.getMin() == Double.POSITIVE_INFINITY || xAxis.getMax() == Double.POSITIVE_INFINITY) {
-      throw new IllegalArgumentException(
-          "Series data (accounting for error bars too) cannot be equal to Double.POSITIVE_INFINITY!!!");
-    }
+    checkAxisForPositiveInfinity(xAxis);
     for (Axis<ST, S> ya : yAxisMap.values()) {
-      if (ya.getMin() == Double.POSITIVE_INFINITY || ya.getMax() == Double.POSITIVE_INFINITY) {
-        throw new IllegalArgumentException(
-            "Series data (accounting for error bars too) cannot be equal to Double.POSITIVE_INFINITY!!!");
-      }
-      if (ya.getMin() == Double.NEGATIVE_INFINITY || ya.getMax() == Double.NEGATIVE_INFINITY) {
-        throw new IllegalArgumentException(
-            "Series data (accounting for error bars too) cannot be equal to Double.NEGATIVE_INFINITY!!!");
-      }
-    }
-
-    if (xAxis.getMin() == Double.NEGATIVE_INFINITY || xAxis.getMax() == Double.NEGATIVE_INFINITY) {
-      throw new IllegalArgumentException(
-          "Series data (accounting for error bars too) cannot be equal to Double.NEGATIVE_INFINITY!!!");
+      checkAxisForPositiveInfinity(ya);
+      checkAxisForNegativeInfinity(ya);
     }
+    checkAxisForNegativeInfinity(xAxis);
   }
 
   /**
@@ -529,4 +516,18 @@ Axis<ST, S> getRightMainYAxis() {
 
     return rightMainYAxis;
   }
+
+  private void checkAxisForPositiveInfinity(Axis<ST, S> axis) {
+    if (axis.getMin() == Double.POSITIVE_INFINITY || axis.getMax() == Double.POSITIVE_INFINITY) {
+      throw new IllegalArgumentException(
+              "Series data (accounting for error bars too) cannot be equal to Double.POSITIVE_INFINITY!!!");
+    }
+  }
+
+  private void checkAxisForNegativeInfinity(Axis<ST, S> axis) {
+    if (axis.getMin() == Double.NEGATIVE_INFINITY || axis.getMax() == Double.NEGATIVE_INFINITY) {
+      throw new IllegalArgumentException(
+              "Series data (accounting for error bars too) cannot be equal to Double.NEGATIVE_INFINITY!!!");
+    }
+  }
 }

xchart/src/main/java/org/knowm/xchart/internal/chartpart/Chart.java

@@ -3,6 +3,8 @@
 import java.awt.Graphics2D;
 import java.awt.RenderingHints;
 import java.awt.Shape;
+import java.awt.font.FontRenderContext;
+import java.awt.font.TextLayout;
 import java.awt.geom.Rectangle2D;
 import java.text.DecimalFormat;
 import java.text.Format;
@@ -159,6 +161,28 @@ public void setYAxisGroupTitle(int yAxisGroup, String yAxisTitle) {
     yAxisGroupTitleMap.put(yAxisGroup, yAxisTitle);
   }
 
+  public Rectangle2D getBoundsHint() {
+
+    if (this.getStyler().isChartTitleVisible() && this.getTitle().length() > 0) {
+
+      TextLayout textLayout =
+          new TextLayout(
+              this.getTitle(),
+              this.getStyler().getChartTitleFont(),
+              new FontRenderContext(null, true, false));
+      Rectangle2D rectangle = textLayout.getBounds();
+      double width = 2 * this.getStyler().getChartTitlePadding() + rectangle.getWidth();
+      double height = 2 * this.getStyler().getChartTitlePadding() + rectangle.getHeight();
+
+      return new Rectangle2D.Double(
+          Double.NaN, Double.NaN, width, height); // Double.NaN indicates not sure yet.
+    } else {
+      return new Rectangle2D
+          .Double(); // Constructs a new Rectangle2D, initialized to location (0, 0) and size (0,
+      // 0).
+    }
+  }
+
   public void addAnnotation(Annotation annotation) {
 
     annotations.add(annotation);

xchart/src/main/java/org/knowm/xchart/internal/chartpart/ChartTitle.java

@@ -99,35 +99,13 @@ public void paint(Graphics2D g) {
    *
    * @return a Rectangle2D defining the height of the chart title including the chart title padding
    */
-  private Rectangle2D getBoundsHint() {
-
-    if (chart.getStyler().isChartTitleVisible() && chart.getTitle().length() > 0) {
-
-      TextLayout textLayout =
-          new TextLayout(
-              chart.getTitle(),
-              chart.getStyler().getChartTitleFont(),
-              new FontRenderContext(null, true, false));
-      Rectangle2D rectangle = textLayout.getBounds();
-      double width = 2 * chart.getStyler().getChartTitlePadding() + rectangle.getWidth();
-      double height = 2 * chart.getStyler().getChartTitlePadding() + rectangle.getHeight();
-
-      return new Rectangle2D.Double(
-          Double.NaN, Double.NaN, width, height); // Double.NaN indicates not sure yet.
-    } else {
-      return new Rectangle2D
-          .Double(); // Constructs a new Rectangle2D, initialized to location (0, 0) and size (0,
-      // 0).
-    }
-  }
-
   @Override
   public Rectangle2D getBounds() {
 
     if (bounds
         == null) { // was not drawn fully yet, just need the height hint. The Plot object will be
       // asking for it.
-      bounds = getBoundsHint();
+      bounds = chart.getBoundsHint();
     }
     return bounds;
   }

xchart/src/main/java/org/knowm/xchart/internal/chartpart/ChartZoom.java

@@ -72,9 +72,9 @@ public void paint(Graphics2D g) {
     // or 2. nothing should be drawn or 3. the zoom area
     //    should be drawn
 
-    if (resetButton.visible && (x1 == -1 || x2 == -1)) { //
+    if (isResetButtonVisibleAndInvalidXCoordinates(x1, x2)) { //
       resetButton.paint(g);
-    } else if (x1 == -1 || x2 == -1) {
+    } else if (isEitherXInvalid(x1, x2)) {
       return;
     } else {
       g.setColor(xyChart.getStyler().getZoomSelectionColor());
@@ -241,4 +241,16 @@ private boolean isOverlapping() {
     }
     return isOverlapping;
   }
+
+  private boolean isResetButtonVisible() {
+    return resetButton.visible;
+  }
+
+  private boolean isEitherXInvalid(int x1, int x2) {
+    return x1 == -1 || x2 == -1;
+  }
+
+  private boolean isResetButtonVisibleAndInvalidXCoordinates(int x1, int x2) {
+    return isResetButtonVisible() && isEitherXInvalid(x1, x2);
+  }
 }

xchart/src/test/java/org/knowm/xchart/CategoryChartTest.java

@@ -12,7 +12,6 @@
 import org.knowm.xchart.custom.CustomGraphic;
 import org.knowm.xchart.custom.CustomTheme;
 import org.knowm.xchart.internal.series.Series;
-import org.knowm.xchart.style.Styler;
 
 public class CategoryChartTest {
 
@@ -25,20 +24,11 @@ void setUp() {
 
   @Test
   void constructor() {
-    CategoryChartBuilder builder =
-        new CategoryChartBuilder()
-            .width(800)
-            .height(600)
-            .theme(Styler.ChartTheme.GGPlot2)
-            .title("CategoryChart")
-            .xAxisTitle("x-axis")
-            .yAxisTitle("y-axis");
 
     assertAll(
         () -> assertDoesNotThrow(() -> new CategoryChart(800, 600)),
         () -> assertDoesNotThrow(() -> new CategoryChart(800, 600, new CustomTheme())),
-        () -> assertDoesNotThrow(() -> new CategoryChart(800, 600, XChart)),
-        () -> assertDoesNotThrow(() -> new CategoryChart(builder)));
+        () -> assertDoesNotThrow(() -> new CategoryChart(800, 600, XChart)));
   }
 
   @Test