Restructured the exercise

- added Functions.java
- refactored FunctionMap.java
- implemented FunctionsTest.java

Author: Taras

math-functions-factory/src/main/java/com.bobocode/FunctionFactory.java

@@ -9,14 +9,6 @@
     </parent>
     <modelVersion>4.0.0</modelVersion>
 
-    <artifactId>math-functions-factory</artifactId>
-
-    <dependencies>
-        <dependency>
-            <groupId>junit</groupId>
-            <artifactId>junit</artifactId>
-            <version>4.12</version>
-        </dependency>
-    </dependencies>
+    <artifactId>math-functions</artifactId>
 
 </project>

math-functions-factory/src/test/java/com/bobocode/FunctionFactoryTest.java

@@ -0,0 +1,29 @@
+package com.bobocode;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Function;
+
+/**
+ * FunctionMap is an API that allows you to store and retrieve functions by string name. FunctionMap are stored in a
+ * HashMap, where the key is a function name, and the value is a Function<T,R> instance
+ */
+public class FunctionMap<T, R> {
+    private Map<String, Function<T, R>> functionMap;
+
+    FunctionMap() {
+        functionMap = new HashMap<>();
+    }
+
+    public void addFunction(String name, Function<T, R> function) {
+        functionMap.put(name, function);
+    }
+
+    public Function<T, R> getFunction(String name) {
+        if (functionMap.containsKey(name)) {
+            return functionMap.get(name);
+        } else {
+            throw new InvalidFunctionNameException(name);
+        }
+    }
+}

math-functions-factory/pom.xml math-functions/pom.xmlmath-functions-factory/pom.xml renamed to math-functions/pom.xml

@@ -0,0 +1,21 @@
+package com.bobocode;
+
+public class Functions {
+    /**
+     * A static factory method that creates an integer function map with basic functions:
+     * - abs (absolute value)
+     * - sgn (signum function)
+     * - increment
+     * - decrement
+     * - square
+     *
+     * @return an instance of {@link FunctionMap} that contains all listed functions
+     */
+    public static FunctionMap<Integer, Integer> intFunctionMap() {
+        FunctionMap<Integer, Integer> intFunctionMap = new FunctionMap<>();
+
+        // todo: add simple functions to the function map (abs, sng, increment, decrement, square)
+
+        return intFunctionMap;
+    }
+}

math-functions/src/main/java/com.bobocode/FunctionMap.java

@@ -0,0 +1,85 @@
+package com.bobocode;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.function.Function;
+
+import static org.junit.Assert.assertEquals;
+
+public class FunctionsTest {
+    private FunctionMap<Integer, Integer> integerFunctionMap;
+
+    @Before
+    public void init(){
+        integerFunctionMap = Functions.intFunctionMap();
+    }
+
+    @Test
+    public void testSquareFunction() {
+        Function<Integer, Integer> squareFunction = integerFunctionMap.getFunction("square");
+
+        int actualResult = squareFunction.apply(5);
+
+        assertEquals(25, actualResult);
+    }
+
+    @Test
+    public void testAbsFunction(){
+        Function<Integer, Integer> absFunction = integerFunctionMap.getFunction("abs");
+
+        int actualResult = absFunction.apply(-192);
+
+        assertEquals(192, actualResult);
+    }
+
+    @Test
+    public void testIncrementFunction(){
+        Function<Integer, Integer> incrementFunction = integerFunctionMap.getFunction("increment");
+
+        int actualResult = incrementFunction.apply(399);
+
+        assertEquals(400, actualResult);
+    }
+
+    @Test
+    public void testDecrementFunction(){
+        Function<Integer, Integer> decrementFunction = integerFunctionMap.getFunction("decrement");
+
+        int actualResult = decrementFunction.apply(800);
+
+        assertEquals(799, actualResult);
+    }
+
+    @Test
+    public void testSignFunctionOnNegativeValue(){
+        Function<Integer, Integer> signFunction = integerFunctionMap.getFunction("sgn");
+
+        int actualResult = signFunction.apply(-123);
+
+        assertEquals(-1, actualResult);
+    }
+
+    @Test
+    public void testSignFunctionOnPositiveValue(){
+        Function<Integer, Integer> signFunction = integerFunctionMap.getFunction("sgn");
+
+        int actualResult = signFunction.apply(23);
+
+        assertEquals(1, actualResult);
+    }
+
+    @Test
+    public void testSignFunctionOnZero(){
+        Function<Integer, Integer> signFunction = integerFunctionMap.getFunction("sgn");
+
+        int actualResult = signFunction.apply(0);
+
+        assertEquals(0, actualResult);
+    }
+
+    @Test(expected = InvalidFunctionNameException.class)
+    public void testSqrtFunction(){
+        integerFunctionMap.getFunction("sqrt");
+    }
+}

math-functions/src/main/java/com.bobocode/Functions.java

@@ -9,12 +9,20 @@
     <packaging>pom</packaging>
     <version>1.0-SNAPSHOT</version>
     <modules>
-        <module>math-functions-factory</module>
+        <module>math-functions</module>
     </modules>
 
     <properties>
         <maven.compiler.source>1.8</maven.compiler.source>
         <maven.compiler.target>1.8</maven.compiler.target>
     </properties>
 
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.12</version>
+        </dependency>
+    </dependencies>
+
 </project>