Part1 by Iurii Salnikov

src/test/java/lambda/part1/exercise/Lambdas01Exercise.java

@@ -1,5 +1,8 @@
 package lambda.part1.exercise;
 
+import com.google.common.base.Optional;
+import com.google.common.base.Predicate;
+import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableList;
 import data.Person;
 import org.junit.Test;
@@ -21,7 +24,12 @@ public void sortPersonsByAge() {
                 new Person("name 2", "lastName 1", 30)
         };
 
-        // TODO use Arrays.sort
+        Arrays.sort(persons, new Comparator<Person>() {
+            @Override
+            public int compare(Person p1, Person p2) {
+                return Integer.compare(p1.getAge(), p2.getAge());
+            }
+        });
 
         assertArrayEquals(persons, new Person[]{
                 new Person("name 3", "lastName 3", 20),
@@ -40,7 +48,16 @@ public void findFirstWithAge30() {
 
         Person person = null;
 
-        // TODO use FluentIterable
+        final Optional<Person> personOptional =
+                FluentIterable.from(persons).firstMatch(new Predicate<Person>() {
+                    @Override
+                    public boolean apply(Person person) {
+                        return person.getAge() == 30;
+                    }
+                });
+
+        if (personOptional.isPresent())
+            person = personOptional.get();
 
         assertEquals(person, new Person("name 1", "lastName 2", 30));
     }

src/test/java/lambda/part1/exercise/Lambdas02Exercise.java

@@ -1,9 +1,13 @@
 package lambda.part1.exercise;
 
+import com.google.common.base.Optional;
+import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableList;
 import data.Person;
 import org.junit.Test;
 
+import java.util.Arrays;
+import java.util.Comparator;
 import java.util.List;
 
 import static org.junit.Assert.assertArrayEquals;
@@ -18,7 +22,7 @@ public void sortPersonsByAge() {
                 new Person("name 2", "lastName 1", 30)
         };
 
-        // TODO use Arrays.sort
+        Arrays.sort(persons, Comparator.comparingInt(p -> p.getAge()));
 
         assertArrayEquals(persons, new Person[]{
                 new Person("name 3", "lastName 3", 20),
@@ -37,7 +41,11 @@ public void findFirstWithAge30() {
 
         Person person = null;
 
-        // TODO use FluentIterable
+        final Optional<Person> personOptional =
+                FluentIterable.from(persons).firstMatch(p -> p.getAge() == 30);
+
+        if (personOptional.isPresent())
+            person = personOptional.get();
 
         assertEquals(person, new Person("name 1", "lastName 2", 30));
     }

src/test/java/lambda/part1/exercise/Lambdas03Exercise.java

@@ -17,22 +17,29 @@ default T twice(T t) {
     }
 
     @Test
-    public void generic0() {
-        final GenericProduct<Integer> prod = null; // Use anonymous class
+    public void generic0() { // Use anonymous class
+        final GenericProduct<Integer> prod = new GenericProduct<Integer>() {
+            @Override
+            public Integer prod(Integer a, int i) {
+                return a * i;
+            }
+        };
 
         assertEquals(prod.prod(3, 2), Integer.valueOf(6));
     }
 
     @Test
-    public void generic1() {
-        final GenericProduct<Integer> prod = null; // Use statement lambda
+    public void generic1() { // Use statement lambda
+        final GenericProduct<Integer> prod = (a, i) -> {
+            return a * i;
+        };
 
         assertEquals(prod.prod(3, 2), Integer.valueOf(6));
     }
 
     @Test
-    public void generic2() {
-        final GenericProduct<Integer> prod = null; // Use expression lambda
+    public void generic2() { // Use expression lambda
+        final GenericProduct<Integer> prod = (a, i) -> a * i;
 
         assertEquals(prod.prod(3, 2), Integer.valueOf(6));
     }
@@ -46,8 +53,8 @@ private static String stringProd(String s, int i) {
     }
 
     @Test
-    public void strSum() {
-        final GenericProduct<String> prod = null; // use stringProd;
+    public void strSum() { // Use stringProd
+        final GenericProduct<String> prod = Lambdas03Exercise::stringProd;
 
         assertEquals(prod.prod("a", 2), "aa");
     }
@@ -63,8 +70,8 @@ private String stringSumWithDelimeter(String s, int i) {
     }
 
     @Test
-    public void strSum2() {
-        final GenericProduct<String> prod = null; // use stringSumWithDelimeter;
+    public void strSum2() { // Use stringSumWithDelimeter
+        final GenericProduct<String> prod = this::stringSumWithDelimeter;
 
         assertEquals(prod.prod("a", 3), "a-a-a");
     }