From 3b473329ea8cd29251331d63377962d597e62bae Mon Sep 17 00:00:00 2001
From: OliE <olie.xdev@googlemail.com>
Date: Mon, 26 Feb 2018 17:33:54 +0100
Subject: [PATCH] use generic java reflection to divide and add scale
 measurements

---
 .../core/datatypes/ScaleMeasurement.java      | 47 ++++++++++++-------
 .../com/health/openscale/MeasurementTest.java | 34 ++++++++++++--
 2 files changed, 59 insertions(+), 22 deletions(-)

diff --git a/android_app/app/src/main/java/com/health/openscale/core/datatypes/ScaleMeasurement.java b/android_app/app/src/main/java/com/health/openscale/core/datatypes/ScaleMeasurement.java
index a0e93c3e..07154319 100644
--- a/android_app/app/src/main/java/com/health/openscale/core/datatypes/ScaleMeasurement.java
+++ b/android_app/app/src/main/java/com/health/openscale/core/datatypes/ScaleMeasurement.java
@@ -106,25 +106,38 @@ public class ScaleMeasurement implements Cloneable {
     }
 
     public void add(final ScaleMeasurement summand) {
-        weight += summand.getWeight();
-        fat += summand.getFat();
-        water += summand.getWater();
-        muscle += summand.getMuscle();
-        lbw += summand.getLbw();
-        bone += summand.getBone();
-        waist += summand.getWaist();
-        hip += summand.getHip();
+        try {
+            Field[] fields = getClass().getDeclaredFields();
+
+            for (Field field : fields) {
+                field.setAccessible(true);
+                Object value = field.get(this);
+
+                if (value != null && Float.class.isAssignableFrom(value.getClass())) {
+                    field.set(this, (float)value + (float)field.get(summand));
+                }
+                field.setAccessible(false);
+            }
+        } catch (IllegalAccessException e) {
+            Log.e("ScaleMeasurement", "Error: " + e.getMessage());
+        }
     }
 
     public void divide(final float divisor) {
-        weight /= divisor;
-        fat /= divisor;
-        water /= divisor;
-        muscle /= divisor;
-        lbw /= divisor;
-        bone /= divisor;
-        waist /= divisor;
-        hip /= divisor;
+        try {
+            Field[] fields = getClass().getDeclaredFields();
+
+            for (Field field : fields) {
+                field.setAccessible(true);
+                Object value = field.get(this);
+                if (value != null && Float.class.isAssignableFrom(value.getClass())) {
+                    field.set(this, (float)value / divisor);
+                }
+                field.setAccessible(false);
+            }
+        } catch (IllegalAccessException e) {
+            Log.e("ScaleMeasurement", "Error: " + e.getMessage());
+        }
     }
 
     public void merge(ScaleMeasurement measurements) {
@@ -134,7 +147,7 @@ public class ScaleMeasurement implements Cloneable {
             for (Field field : fields) {
                 field.setAccessible(true);
                 Object value = field.get(measurements);
-                if (Float.class.isAssignableFrom(value.getClass())) {
+                if (value != null && Float.class.isAssignableFrom(value.getClass())) {
                     if ((float)field.get(this) == 0.0f) {
                         field.set(this, value);
                     }
diff --git a/android_app/app/src/test/java/com/health/openscale/MeasurementTest.java b/android_app/app/src/test/java/com/health/openscale/MeasurementTest.java
index 4bfb1627..908e0407 100644
--- a/android_app/app/src/test/java/com/health/openscale/MeasurementTest.java
+++ b/android_app/app/src/test/java/com/health/openscale/MeasurementTest.java
@@ -17,18 +17,18 @@ package com.health.openscale;
 
 import com.health.openscale.core.datatypes.ScaleMeasurement;
 
+import org.junit.Before;
 import org.junit.Test;
 
 import static junit.framework.Assert.assertEquals;
 
 public class MeasurementTest {
     private static final double DELTA = 1e-15;
+    private ScaleMeasurement measurementA = new ScaleMeasurement();
+    private ScaleMeasurement measurementB = new ScaleMeasurement();
 
-    @Test
-    public void mergeTest() throws InstantiationException, IllegalAccessException {
-        ScaleMeasurement measurementA = new ScaleMeasurement();
-        ScaleMeasurement measurementB = new ScaleMeasurement();
-
+    @Before
+    public void initData() {
         measurementA.setWeight(80.0f);
         measurementA.setBone(3.0f);
         measurementA.setMuscle(55.0f);
@@ -37,7 +37,10 @@ public class MeasurementTest {
         measurementB.setBone(10.0f);
         measurementB.setHip(5.0f);
         measurementB.setWater(12.0f);
+    }
 
+    @Test
+    public void mergeTest() {
         measurementA.merge(measurementB);
 
         assertEquals(80.0f, measurementA.getWeight(), DELTA);
@@ -46,4 +49,25 @@ public class MeasurementTest {
         assertEquals( 12.0f, measurementA.getWater(), DELTA);
         assertEquals( 55.0f, measurementA.getMuscle(), DELTA);
     }
+
+    @Test
+    public void divideTest() {
+        measurementA.divide(2.0f);
+
+        assertEquals(40.0f, measurementA.getWeight(), DELTA);
+        assertEquals(1.5f, measurementA.getBone(), DELTA);
+        assertEquals(27.5f, measurementA.getMuscle(), DELTA);
+        assertEquals(0.0f, measurementA.getWater(), DELTA);
+    }
+
+    @Test
+    public void addTest() {
+        measurementA.add(measurementB);
+
+        assertEquals(170.0f, measurementA.getWeight(), DELTA);
+        assertEquals(13.0f, measurementA.getBone(), DELTA);
+        assertEquals(55.0f, measurementA.getMuscle(), DELTA);
+        assertEquals(12.0f, measurementA.getWater(), DELTA);
+        assertEquals(5.0f, measurementA.getHip(), DELTA);
+    }
 }