introduced factory pattern for ConfidenceBasedAverager

java/com.sap.sailing.domain.test/src/com/sap/sailing/domain/test/ConfidenceTest.java

@@ -9,58 +9,13 @@ import com.sap.sailing.domain.base.Bearing;
 import com.sap.sailing.domain.base.impl.DegreeBearingImpl;
 import com.sap.sailing.domain.base.impl.RadianBearingImpl;
 import com.sap.sailing.domain.common.Util.Pair;
+import com.sap.sailing.domain.confidence.ConfidenceBasedAverager;
+import com.sap.sailing.domain.confidence.ConfidenceBasedAveragerFactory;
 import com.sap.sailing.domain.confidence.HasConfidence;
 import com.sap.sailing.domain.confidence.ScalableValue;
-import com.sap.sailing.domain.confidence.impl.ConfidenceBasedAveragerImpl;
+import com.sap.sailing.domain.confidence.impl.ScalableDoubleWithConfidence;
 
 public class ConfidenceTest {
-    private static class ScalableDouble implements ScalableValue<Double, Double> {
-        private final Double d;
-        
-        public ScalableDouble(Double d) {
-            this.d = d;
-        }
-
-        @Override
-        public ScalableValue<Double, Double> multiply(double factor) {
-            return new ScalableDouble(d * factor);
-        }
-
-        @Override
-        public ScalableValue<Double, Double> add(ScalableValue<Double, Double> t) {
-            return new ScalableDouble(d+t.getValue());
-        }
-
-        @Override
-        public Double divide(double divisor) {
-            return d / divisor;
-        }
-
-        @Override
-        public Double getValue() {
-            return d;
-        }
-    }
-    
-    private static class ScalableDoubleWithConfidence extends ScalableDouble implements HasConfidence<Double, Double> {
-        private final double confidence;
-        
-        public ScalableDoubleWithConfidence(double d, double confidence) {
-            super(d);
-            this.confidence = confidence;
-        }
-        
-        @Override
-        public double getConfidence() {
-            return confidence;
-        }
-
-        @Override
-        public ScalableValue<Double, Double> getScalableValue() {
-            return this;
-        }
-    }
-    
     private static class ScalableBearing implements ScalableValue<Pair<Double, Double>, Bearing> {
         private final double sin;
         private final double cos;
@@ -128,14 +83,16 @@ public class ConfidenceTest {
     
     @Test
     public void testAveragingWithEmptyListYieldsNull() {
+        ConfidenceBasedAverager<Double, Double> averager = ConfidenceBasedAveragerFactory.INSTANCE.createAverager();
         @SuppressWarnings("unchecked")
-        Double average = new ConfidenceBasedAveragerImpl<Double, Double>().getAverage();
+        Double average = averager.getAverage();
         assertNull(average);
     }
 
     @Test
     public void testAveragingWithNullArrayYieldsNull() {
-        Double average = new ConfidenceBasedAveragerImpl<Double, Double>().getAverage((HasConfidence<Double, Double>[]) null);
+        ConfidenceBasedAverager<Double, Double> averager = ConfidenceBasedAveragerFactory.INSTANCE.createAverager();
+        Double average = averager.getAverage((HasConfidence<Double, Double>[]) null);
         assertNull(average);
     }
 
@@ -143,8 +100,9 @@ public class ConfidenceTest {
     public void testAveragingWithTwoDoubles() {
         ScalableDoubleWithConfidence d1 = new ScalableDoubleWithConfidence(1., 0.5);
         ScalableDoubleWithConfidence d2 = new ScalableDoubleWithConfidence(2., 0.5);
+        ConfidenceBasedAverager<Double, Double> averager = ConfidenceBasedAveragerFactory.INSTANCE.createAverager();
         @SuppressWarnings("unchecked")
-        Double average = new ConfidenceBasedAveragerImpl<Double, Double>().getAverage(d1, d2);
+        Double average = averager.getAverage(d1, d2);
         assertEquals(1.5, average, 0.00000001);
     }
 
@@ -153,8 +111,9 @@ public class ConfidenceTest {
         ScalableDoubleWithConfidence d1 = new ScalableDoubleWithConfidence(1., 1.);
         ScalableDoubleWithConfidence d2 = new ScalableDoubleWithConfidence(2., 1.);
         ScalableDoubleWithConfidence d3 = new ScalableDoubleWithConfidence(3., 2.);
+        ConfidenceBasedAverager<Double, Double> averager = ConfidenceBasedAveragerFactory.INSTANCE.createAverager();
         @SuppressWarnings("unchecked")
-        Double average = new ConfidenceBasedAveragerImpl<Double, Double>().getAverage(d1, d2, d3);
+        Double average = averager.getAverage(d1, d2, d3);
         assertEquals(2.25, average, 0.00000001);
     }
     
@@ -162,8 +121,9 @@ public class ConfidenceTest {
     public void testAveragingWithTwoBearings() {
         ScalableBearingWithConfidence d1 = new ScalableBearingWithConfidence(new DegreeBearingImpl(350.), 1.);
         ScalableBearingWithConfidence d2 = new ScalableBearingWithConfidence(new DegreeBearingImpl(10.), 1.);
+        ConfidenceBasedAverager<Pair<Double, Double>, Bearing> averager = ConfidenceBasedAveragerFactory.INSTANCE.createAverager();
         @SuppressWarnings("unchecked")
-        Bearing average = new ConfidenceBasedAveragerImpl<Pair<Double, Double>, Bearing>().getAverage(d1, d2);
+        Bearing average = averager.getAverage(d1, d2);
         assertEquals(0, average.getDegrees(), 0.00000001);
     }
     
@@ -172,8 +132,9 @@ public class ConfidenceTest {
         ScalableBearingWithConfidence d1 = new ScalableBearingWithConfidence(new DegreeBearingImpl(350.), 1.);
         ScalableBearingWithConfidence d2 = new ScalableBearingWithConfidence(new DegreeBearingImpl(10.), 1.);
         ScalableBearingWithConfidence d3 = new ScalableBearingWithConfidence(new DegreeBearingImpl(20.), 2.);
+        ConfidenceBasedAverager<Pair<Double, Double>, Bearing> averager = ConfidenceBasedAveragerFactory.INSTANCE.createAverager();
         @SuppressWarnings("unchecked")
-        Bearing average = new ConfidenceBasedAveragerImpl<Pair<Double, Double>, Bearing>().getAverage(d1, d2, d3);
+        Bearing average = averager.getAverage(d1, d2, d3);
         assertEquals(10, average.getDegrees(), 0.1);
     }
     

java/com.sap.sailing.domain/src/com/sap/sailing/domain/confidence/AbstractScalarValue.java

@@ -0,0 +1,11 @@
+package com.sap.sailing.domain.confidence;
+
+/**
+ * A {@link ScalableValue} where the <code>ValueType</code> and the <code>AveragesTo</code> type are both the same because
+ * the value type is itself scalable, offering addition, multiplication and division.
+ * 
+ * @author Axel Uhl (d043530)
+ *
+ */
+public interface AbstractScalarValue<T> extends ScalableValue<T, T> {
+}

java/com.sap.sailing.domain/src/com/sap/sailing/domain/confidence/ConfidenceBasedAverager.java

@@ -0,0 +1,5 @@
+package com.sap.sailing.domain.confidence;
+
+public interface ConfidenceBasedAverager<ValueType, AveragesTo> {
+    AveragesTo getAverage(HasConfidence<ValueType, AveragesTo>... values);
+}

java/com.sap.sailing.domain/src/com/sap/sailing/domain/confidence/ConfidenceBasedAveragerFactory.java

@@ -0,0 +1,9 @@
+package com.sap.sailing.domain.confidence;
+
+import com.sap.sailing.domain.confidence.impl.ConfidenceBasedAveragerFactoryImpl;
+
+public interface ConfidenceBasedAveragerFactory {
+    ConfidenceBasedAveragerFactory INSTANCE = new ConfidenceBasedAveragerFactoryImpl();
+    
+    <ValueType, AveragesTo> ConfidenceBasedAverager<ValueType, AveragesTo> createAverager();
+}

java/com.sap.sailing.domain/src/com/sap/sailing/domain/confidence/impl/ConfidenceBasedAveragerFactoryImpl.java

@@ -0,0 +1,13 @@
+package com.sap.sailing.domain.confidence.impl;
+
+import com.sap.sailing.domain.confidence.ConfidenceBasedAverager;
+import com.sap.sailing.domain.confidence.ConfidenceBasedAveragerFactory;
+
+public class ConfidenceBasedAveragerFactoryImpl implements ConfidenceBasedAveragerFactory {
+
+    @Override
+    public <ValueType, AveragesTo> ConfidenceBasedAverager<ValueType, AveragesTo> createAverager() {
+        return new ConfidenceBasedAveragerImpl<ValueType, AveragesTo>();
+    }
+
+}

java/com.sap.sailing.domain/src/com/sap/sailing/domain/confidence/impl/ConfidenceBasedAveragerImpl.java

@@ -1,5 +1,6 @@
 package com.sap.sailing.domain.confidence.impl;
 
+import com.sap.sailing.domain.confidence.ConfidenceBasedAverager;
 import com.sap.sailing.domain.confidence.HasConfidence;
 import com.sap.sailing.domain.confidence.ScalableValue;
 
@@ -25,11 +26,9 @@ import com.sap.sailing.domain.confidence.ScalableValue;
  * devices produce some statistical errors, no matter how small (cf. Heisenberg ;-) ).
  * 
  * @author Axel Uhl (d043530)
- * 
- * @param <T>
- *            the type of value to be scaled / averaged using their confidence
  */
-public class ConfidenceBasedAveragerImpl<ValueType, AveragesTo> {
+public class ConfidenceBasedAveragerImpl<ValueType, AveragesTo> implements ConfidenceBasedAverager<ValueType, AveragesTo> {
+    @Override
     public AveragesTo getAverage(HasConfidence<ValueType, AveragesTo>... values) {
         if (values == null || values.length == 0) {
             return null;

java/com.sap.sailing.domain/src/com/sap/sailing/domain/confidence/impl/ScalableDouble.java

@@ -0,0 +1,33 @@
+package com.sap.sailing.domain.confidence.impl;
+
+import com.sap.sailing.domain.confidence.AbstractScalarValue;
+import com.sap.sailing.domain.confidence.ScalableValue;
+
+public class ScalableDouble implements AbstractScalarValue<Double> {
+    private final double value;
+    
+    public ScalableDouble(double value) {
+        this.value = value;
+    }
+    
+    @Override
+    public ScalableValue<Double, Double> multiply(double factor) {
+        return new ScalableDouble(factor*getValue());
+    }
+
+    @Override
+    public ScalableDouble add(ScalableValue<Double, Double> t) {
+        return new ScalableDouble(getValue()+t.getValue());
+    }
+
+    @Override
+    public Double divide(double divisor) {
+        return getValue()/divisor;
+    }
+
+    @Override
+    public Double getValue() {
+        return value;
+    }
+
+}

java/com.sap.sailing.domain/src/com/sap/sailing/domain/confidence/impl/ScalableDoubleWithConfidence.java

@@ -0,0 +1,22 @@
+package com.sap.sailing.domain.confidence.impl;
+
+import com.sap.sailing.domain.confidence.HasConfidence;
+
+public class ScalableDoubleWithConfidence extends ScalableDouble implements HasConfidence<Double, Double> {
+    private final double confidence;
+    
+    public ScalableDoubleWithConfidence(double d, double confidence) {
+        super(d);
+        this.confidence = confidence;
+    }
+    
+    @Override
+    public double getConfidence() {
+        return confidence;
+    }
+
+    @Override
+    public ScalableDouble getScalableValue() {
+        return this;
+    }
+}