Added adapter pattern and its test case

src/main/java/com/conversions/BinaryToHexadecimal.java

@@ -36,7 +36,7 @@ public String binToHex(String binStr) {
         String hex = "";
 
         int currentBit;
-        BigInteger tenValue = new BigInteger("10");
+        BigInteger tenValue = BigInteger.valueOf(10);
         while (binary.compareTo(BigInteger.ZERO) != 0) {
             // to store decimal equivalent of number formed by 4 decimal digits
             int code4 = 0;

src/main/java/com/conversions/DecimalToHexadecimal.java

@@ -4,7 +4,7 @@
 
 public class DecimalToHexadecimal {
     private static final char[] hexChars = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
-    private static final BigInteger valueHex = new BigInteger("16");
+    private static final BigInteger valueHex = BigInteger.valueOf(16);
 
     /**
      * This method converts and decimal number to a Hexadecimal number

src/main/java/com/conversions/DecimalToOctal.java

@@ -4,7 +4,7 @@
 
 public class DecimalToOctal {
     private static final char[] octalChars = {'0', '1', '2', '3', '4', '5', '6', '7'};
-    private static final BigInteger valueOctal = new BigInteger("8");
+    private static final BigInteger valueOctal = BigInteger.valueOf(8);
 
     /**
      * This method converts and decimal number to a octal number

src/main/java/com/designpatterns/structural/adapter/BugattiVeyron.java

@@ -0,0 +1,8 @@
+package src.main.java.com.designpatterns.structural.adapter;
+
+public class BugattiVeyron implements Movable {
+    @Override
+    public double getSpeed() {
+        return 268;
+    }
+}

src/main/java/com/designpatterns/structural/adapter/Movable.java

@@ -0,0 +1,6 @@
+package src.main.java.com.designpatterns.structural.adapter;
+
+public interface Movable {
+    // Returns the speed of the movable in MPH
+    double getSpeed();
+}

src/main/java/com/designpatterns/structural/adapter/MovableAdapter.java

@@ -0,0 +1,16 @@
+package src.main.java.com.designpatterns.structural.adapter;
+
+/**
+ * An Adapter pattern acts as a connector between two incompatible interfaces that otherwise cannot be connected
+ * directly. An Adapter wraps an existing class with a new interface so that it becomes compatible with the client’s
+ * interface.
+ * <br>
+ * The main motive behind using this pattern is to convert an existing interface into another interface that the client
+ * expects. It’s usually implemented once the application is designed.
+ *
+ * @see <a href="https://en.wikipedia.org/wiki/Adapter_pattern">Adapter Pattern</a>
+ */
+public interface MovableAdapter {
+    // Returns the speed of the movable in KPH
+    double getSpeed();
+}

src/main/java/com/designpatterns/structural/adapter/MovableAdapterImpl.java

@@ -0,0 +1,18 @@
+package src.main.java.com.designpatterns.structural.adapter;
+
+public class MovableAdapterImpl implements MovableAdapter {
+    private Movable luxuryCars;
+
+    public MovableAdapterImpl(Movable luxuryCars) {
+        this.luxuryCars = luxuryCars;
+    }
+
+    @Override
+    public double getSpeed() {
+        return convertMPHtoKMPH(luxuryCars.getSpeed());
+    }
+
+    private double convertMPHtoKMPH(double mph) {
+        return mph * 1.60934;
+    }
+}

src/test/java/com/designpatterns/structural/adapter/MovableAdapterTest.java

@@ -0,0 +1,18 @@
+package src.test.java.com.designpatterns.structural.adapter;
+
+import org.junit.Test;
+import src.main.java.com.designpatterns.structural.adapter.BugattiVeyron;
+import src.main.java.com.designpatterns.structural.adapter.Movable;
+import src.main.java.com.designpatterns.structural.adapter.MovableAdapter;
+import src.main.java.com.designpatterns.structural.adapter.MovableAdapterImpl;
+
+import static org.junit.Assert.assertEquals;
+
+public class MovableAdapterTest {
+    @Test
+    public void testMovableAdapter() {
+        Movable bugattiVeyron = new BugattiVeyron();
+        MovableAdapter bugattiVeyronAdapter = new MovableAdapterImpl(bugattiVeyron);
+        assertEquals(bugattiVeyronAdapter.getSpeed(), 431.30312, 0.00001);
+    }
+}