Improve the Resolution implementation and add some tests.

src/de/gurkenlabs/litiengine/gui/screens/Resolution.java

@@ -1,79 +1,249 @@
 package de.gurkenlabs.litiengine.gui.screens;
 
 import java.awt.Dimension;
-
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+import de.gurkenlabs.litiengine.GameWindow;
+
+/**
+ * Represents the resolution of the game window consisting of the width and height and information about the ratio.
+ * 
+ * <p>
+ * This class also provides access to predefined known resolutions of the different aspect ratios which can be used
+ * to set the resolution of the <code>GameWindow</code>.
+ * </p>
+ * <ul>
+ * <li>{@link Ratio4x3}</li>
+ * <li>{@link Ratio5x4}</li>
+ * <li>{@link Ratio16x9}</li>
+ * <li>{@link Ratio16x10}</li>
+ * </ul>
+ *
+ * @see GameWindow#setResolution(Resolution)
+ */
 public class Resolution {
-  public static final String R_4X3 = "4x3";
-  public static final String R_5X4 = "5x4";
-  public static final String R_16X9 = "16x9";
-  public static final String R_16X10 = "16x10";
+  private static final Logger log = Logger.getLogger(Resolution.class.getName());
 
   private final int width;
   private final int height;
   private final Dimension dimension;
-  private final String ratio;
+  private final Ratio ratio;
 
-  private Resolution(int width, int height, String ratio) {
+  private Resolution(int width, int height, Ratio ratio) {
     this.width = width;
     this.height = height;
     this.dimension = new Dimension(this.getWidth(), this.getHeight());
     this.ratio = ratio;
   }
 
   public static Resolution custom(int width, int height, String resolutionName) {
-    return new Resolution(width, height, resolutionName);
+    return new Resolution(width, height, new Ratio(width, height, resolutionName));
   }
 
+  /**
+   * Gets the height of this resolution.
+   * 
+   * @return The height of the resolution.
+   */
   public int getHeight() {
     return this.height;
   }
 
+  /**
+   * Gets the width of this resolution.
+   * 
+   * @return The width of the resolution.
+   */
   public int getWidth() {
     return this.width;
   }
 
+  /**
+   * Gets the dimension of this resolution consisting of it's width and height.
+   * 
+   * @return The dimension of the resolution.
+   */
   public Dimension getDimension() {
     return this.dimension;
   }
 
-  public String getRatio() {
+  public String toDimensionString() {
+    return this.toDimensionString("x");
+  }
+
+  public String toDimensionString(String delimiter) {
+    return this.getWidth() + delimiter + this.getHeight();
+  }
+
+  @Override
+  public String toString() {
+    return this.toDimensionString();
+  }
+
+  /**
+   * Gets the aspect ratio of this resolution.
+   * 
+   * @return The aspect ratio of this resolution.
+   */
+  public Ratio getRatio() {
     return this.ratio;
   }
 
-  public static class Ratio4x3 {
-    public static final Resolution RES_1024x768 = new Resolution(1024, 768, R_4X3);
+  /**
+   * Contains predefined <code>Resolutions</code> with an aspect ratio of 4:3.
+   */
+  public static class Ratio4x3 extends Ratio {
+    public static final Resolution RES_1024x768 = new Resolution(1024, 768, new Ratio4x3());
 
     private Ratio4x3() {
+      super(4, 3);
+    }
+
+    /**
+     * Gets all predefined resolutions with an aspect ratio of 4:3.
+     * 
+     * @return All predefined resolutions with an aspect ratio of 4:3.
+     */
+    public static List<Resolution> getAll() {
+      return getAll(Ratio4x3.class);
     }
   }
 
-  public static class Ratio5x4 {
-    public static final Resolution RES_1280x1024 = new Resolution(1280, 1024, R_5X4);
+  /**
+   * Contains predefined <code>Resolutions</code> with an aspect ratio of 5:4.
+   */
+  public static class Ratio5x4 extends Ratio {
+    public static final Resolution RES_1280x1024 = new Resolution(1280, 1024, new Ratio5x4());
 
     private Ratio5x4() {
+      super(5, 4);
+    }
+
+    /**
+     * Gets all predefined resolutions with an aspect ratio of 5:4.
+     * 
+     * @return All predefined resolutions with an aspect ratio of 5:4.
+     */
+    public static List<Resolution> getAll() {
+      return getAll(Ratio5x4.class);
     }
   }
 
-  public static class Ratio16x9 {
-    public static final Resolution RES_1280x720 = new Resolution(1280, 720, R_16X9);
-    public static final Resolution RES_1360x768 = new Resolution(1360, 768, R_16X9);
-    public static final Resolution RES_1366x768 = new Resolution(1366, 768, R_16X9);
-    public static final Resolution RES_1536x864 = new Resolution(1536, 864, R_16X9);
-    public static final Resolution RES_1600x900 = new Resolution(1600, 900, R_16X9);
-    public static final Resolution RES_1920x1080 = new Resolution(1920, 1080, R_16X9);
-    public static final Resolution RES_2560x1440 = new Resolution(2560, 1440, R_16X9);
+  /**
+   * Contains predefined <code>Resolutions</code> with an aspect ratio of 16:9.
+   */
+  public static class Ratio16x9 extends Ratio {
+    public static final Resolution RES_1280x720 = new Resolution(1280, 720, new Ratio16x9());
+    public static final Resolution RES_1360x768 = new Resolution(1360, 768, new Ratio16x9());
+    public static final Resolution RES_1366x768 = new Resolution(1366, 768, new Ratio16x9());
+    public static final Resolution RES_1536x864 = new Resolution(1536, 864, new Ratio16x9());
+    public static final Resolution RES_1600x900 = new Resolution(1600, 900, new Ratio16x9());
+    public static final Resolution RES_1920x1080 = new Resolution(1920, 1080, new Ratio16x9());
+    public static final Resolution RES_2560x1440 = new Resolution(2560, 1440, new Ratio16x9());
 
     private Ratio16x9() {
+      super(16, 9);
+    }
+
+    /**
+     * Gets all predefined resolutions with an aspect ratio of 16:9.
+     * 
+     * @return All predefined resolutions with an aspect ratio of 16:9.
+     */
+    public static List<Resolution> getAll() {
+      return getAll(Ratio16x9.class);
     }
   }
 
-  public static class Ratio16x10 {
-    public static final Resolution RES_1280x800 = new Resolution(1280, 800, R_16X10);
-    public static final Resolution RES_1440x900 = new Resolution(1440, 900, R_16X10);
-    public static final Resolution RES_1680x1050 = new Resolution(1680, 1050, R_16X10);
-    public static final Resolution RES_1920x1200 = new Resolution(1920, 1200, R_16X10);
+  /**
+   * Contains predefined <code>Resolutions</code> with an aspect ratio of 16:10.
+   */
+  public static class Ratio16x10 extends Ratio {
+    public static final Resolution RES_1280x800 = new Resolution(1280, 800, new Ratio16x10());
+    public static final Resolution RES_1440x900 = new Resolution(1440, 900, new Ratio16x10());
+    public static final Resolution RES_1680x1050 = new Resolution(1680, 1050, new Ratio16x10());
+    public static final Resolution RES_1920x1200 = new Resolution(1920, 1200, new Ratio16x10());
 
     private Ratio16x10() {
+      super(16, 10);
+    }
+
+    /**
+     * Gets all predefined resolutions with an aspect ratio of 16:10.
+     * 
+     * @return All predefined resolutions with an aspect ratio of 16:10.
+     */
+    public static List<Resolution> getAll() {
+      return getAll(Ratio16x10.class);
+    }
+  }
+
+  public static class Ratio {
+    private final String name;
+    private final int x;
+    private final int y;
+
+    protected Ratio(int x, int y) {
+      this(x, y, x + ":" + y);
+    }
+
+    protected Ratio(int x, int y, String name) {
+      this.x = x;
+      this.y = y;
+      this.name = name;
+    }
+
+    protected static List<Resolution> getAll(Class<?> clz) {
+      List<Resolution> resolutions = new ArrayList<>();
+
+      for (final Field field : clz.getDeclaredFields()) {
+        if (field.getType() == Resolution.class && Modifier.isStatic(field.getModifiers()) && Modifier.isPublic(field.getModifiers())) {
+          try {
+            resolutions.add((Resolution) field.get(null));
+          } catch (final IllegalArgumentException | IllegalAccessException e) {
+            log.log(Level.SEVERE, e.getMessage(), e);
+          }
+        }
+      }
+
+      return resolutions;
+    }
+
+    /**
+     * Gets the name of this aspect ratio
+     * 
+     * @return
+     */
+    public String getName() {
+      return this.name;
+    }
+
+    /**
+     * Gets the x-value of this aspect ratio.
+     * 
+     * @return The x-value of this aspect ratio.
+     */
+    public int getX() {
+      return this.x;
+    }
+
+    /**
+     * Gets the y-value of this aspect ratio.
+     * 
+     * @return The y-value of this aspect ratio.
+     */
+    public int getY() {
+      return this.y;
+    }
+
+    @Override
+    public String toString() {
+      return this.getName();
     }
   }
 }

tests/de/gurkenlabs/litiengine/gui/ResolutionTests.java

@@ -0,0 +1,47 @@
+package de.gurkenlabs.litiengine.gui;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import de.gurkenlabs.litiengine.gui.screens.Resolution;
+
+public class ResolutionTests {
+
+  @Test
+  public void testDimensionString() {
+    Resolution res = Resolution.Ratio16x9.RES_1280x720;
+
+    assertEquals("1280x720", res.toDimensionString());
+    assertEquals("1280---720", res.toDimensionString("---"));
+  }
+
+  @Test
+  public void testCorrectRatio() {
+    List<Resolution> resolutions16x9 = Resolution.Ratio16x9.getAll();
+
+    for (Resolution res : resolutions16x9) {
+      assertEquals("16:9", res.getRatio().getName());
+    }
+
+    List<Resolution> resolutions16x10 = Resolution.Ratio16x10.getAll();
+
+    for (Resolution res : resolutions16x10) {
+      assertEquals("16:10", res.getRatio().getName());
+    }
+
+    List<Resolution> resolutions4x3 = Resolution.Ratio4x3.getAll();
+
+    for (Resolution res : resolutions4x3) {
+      assertEquals("4:3", res.getRatio().getName());
+    }
+
+    List<Resolution> resolutions5x4 = Resolution.Ratio5x4.getAll();
+
+    for (Resolution res : resolutions5x4) {
+      assertEquals("5:4", res.getRatio().getName());
+    }
+  }
+}