commit de l'exercice 1 et 2 non terminé

stream-api/src/test/java/stream/api/Exercise1Test.java

@@ -27,8 +27,8 @@ public void findRichCustomers() {
          * Create a {@link Stream} from customerList only including customer who has more budget than 10000.
          * Use lambda expression for Predicate and {@link Stream#filter} for filtering.
          */
-        Predicate<Customer> richCustomerCondition = null;
-        Stream<Customer> richCustomerStream = null;
+        Predicate<Customer> richCustomerCondition = customer -> customer.getBudget() > 10000;
+        Stream<Customer> richCustomerStream = customerList.stream().filter(richCustomerCondition);
 
         assertTrue("Solution for Predicate should be lambda expression", AssertUtil.isLambda(richCustomerCondition));
         List<Customer> richCustomer = richCustomerStream.collect(Collectors.toList());
@@ -45,8 +45,8 @@ public void howOldAreTheCustomers() {
          * Use method reference(best) or lambda expression(okay) for creating {@link Function} which will
          * convert {@link Customer} to {@link Integer}, and then apply it by using {@link Stream#map}.
          */
-        Function<Customer, Integer> getAgeFunction = null;
-        Stream<Integer> ageStream = null;
+        Function<Customer, Integer> getAgeFunction = Customer::getAge;
+        Stream<Integer> ageStream = customerList.stream().map(getAgeFunction);
 
         assertTrue(AssertUtil.isLambda(getAgeFunction));
         List<Integer> richCustomer = ageStream.collect(Collectors.toList());

stream-api/src/test/java/stream/api/Exercise2Test.java

@@ -27,7 +27,7 @@ public void sortByAge() {
          * Create a stream with ascending ordered age values.
          * Use {@link Stream#sorted} to sort them.
          */
-        Stream<Integer> sortedAgeStream = null;
+        Stream<Integer> sortedAgeStream = customerList.stream().map(Customer::getAge).sorted();
 
         List<Integer> sortedAgeList = sortedAgeStream.collect(Collectors.toList());
         assertThat(sortedAgeList, contains(21, 22, 22, 26, 27, 28, 32, 35, 36, 38));
@@ -40,8 +40,8 @@ public void descSortByAge() {
         /**
          * Create a stream with descending ordered age values.
          */
-        Comparator<Integer> descOrder = null;
-        Stream<Integer> sortedAgeStream = null;
+        Comparator<Integer> descOrder = ((o1, o2) -> o1 - o2);
+        Stream<Integer> sortedAgeStream = customerList.stream().map(Customer::getAge).sorted(descOrder);
 
         assertTrue(AssertUtil.isLambda(descOrder));
         List<Integer> sortedAgeList = sortedAgeStream.collect(Collectors.toList());
@@ -55,7 +55,7 @@ public void top3RichCustomer() {
         /**
          * Create a stream with top 3 rich customers using {@link Stream#limit} to limit the size of the stream
          */
-        Stream<String> top3RichCustomerStream = null;
+        Stream<String> top3RichCustomerStream = customerList.stream().sorted((o1, o2) -> o1.getBudget()).map(Customer::getName).limit(3);
 
         List<String> top3RichCustomerList = top3RichCustomerStream.collect(Collectors.toList());
         assertThat(top3RichCustomerList, contains("Diana", "Andrew", "Chris"));
@@ -68,7 +68,7 @@ public void distinctAge() {
         /**
          * Create a stream with distinct age values using {@link Stream#distinct}
          */
-        Stream<Integer> distinctAgeStream = null;
+        Stream<Integer> distinctAgeStream = customerList.stream().map(Customer::getAge).distinct();
 
         List<Integer> distinctAgeList = distinctAgeStream.collect(Collectors.toList());
         assertThat(distinctAgeList, contains(22, 27, 28, 38, 26, 32, 35, 21, 36));
@@ -82,8 +82,8 @@ public void itemsCustomersWantToBuy() {
          * Create a stream with items' names stored in {@link Customer.wantToBuy}
          * Use {@link Stream#flatMap} to create a stream from each element of a stream.
          */
-        Function<Customer, Stream<Item>> getItemStream = null;
-        Stream<String> itemStream = null;
+        Function<Customer, Stream<Item>> getItemStream = customer -> customer.getWantToBuy().stream();
+        Stream<String> itemStream = customerList.stream().flatMap(getItemStream).map(item -> item.getName());
 
         assertTrue(AssertUtil.isLambda(getItemStream));
         List<String> itemList = itemStream.collect(Collectors.toList());