Added exercise binary

binary/build.gradle

@@ -0,0 +1,11 @@
+apply plugin: "java"
+apply plugin: "eclipse"
+apply plugin: "idea"
+
+repositories {
+  mavenCentral()
+}
+
+dependencies {
+  testCompile "junit:junit:4.10"
+}

binary/example.java

@@ -0,0 +1,35 @@
+public class Binary {
+
+    private String binary;
+    private int decimal;
+
+    public Binary(String binary) {
+        this.binary = binary;
+        this.decimal = getDecimalFromBinary(binary);
+    }
+
+    public int getDecimal() {
+        return decimal;
+    }
+
+    private static int getDecimalFromBinary(String binary) {
+        if (!isValid(binary)) {
+            return 0;
+        }
+
+        int sum = 0;
+
+        for (int i = 0; i < binary.length(); i++) {
+            sum += Character.getNumericValue(binary.charAt(i)) * (int) Math.pow(2, binary.length() - i - 1);
+        }
+
+        return sum;
+    }
+
+    private static boolean isValid(String binaryRepresentation) {
+        boolean isValid = binaryRepresentation.chars()
+                .allMatch(x -> Character.isDigit((char) x) && Character.getNumericValue((char) x) < 2);
+
+        return isValid;
+    }
+}

binary/src/main/java/Binary.java

@@ -0,0 +1,2 @@
+public class Binary {
+}

binary/src/test/java/BinaryTest.java

@@ -0,0 +1,47 @@
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.Parameterized;
+import org.junit.runners.Parameterized.Parameters;
+
+import java.util.Arrays;
+import java.util.Collection;
+
+import static org.junit.Assert.assertEquals;
+
+@RunWith(Parameterized.class)
+public class BinaryTest {
+
+    private String input;
+    private int expectedOutput;
+
+    @Parameters
+    public static Collection<Object[]> data() {
+        return Arrays.asList(new Object[][]{
+                {"1", 1},
+                {"10", 2},
+                {"11", 3},
+                {"100", 4},
+                {"1001", 9},
+                {"11010", 26},
+                {"10001101000", 1128},
+                {"2", 0},
+                {"5", 0},
+                {"9", 0},
+                {"134678", 0},
+                {"abc10z", 0},
+                {"011", 3}
+        });
+    }
+
+    public BinaryTest(String input, int expectedOutput) {
+        this.input = input;
+        this.expectedOutput = expectedOutput;
+    }
+
+    @Test
+    public void test() {
+        Binary binary = new Binary(input);
+
+        assertEquals(expectedOutput, binary.getDecimal());
+    }
+}

config.json

@@ -18,7 +18,8 @@
     "gigasecond",
     "triangle",
     "scrabble-score",
-    "roman-numerals"
+    "roman-numerals",
+    "binary"
   ],
   "deprecated": [
   ],