- fix ImperativeVsDeclarativeFiltering.java

- update StreamParallelProcessing.java
- add StreamWhileExample.java

Author: Taras

stream-api/src/main/java/com/bobocode/ImperativeVsDeclarativeFiltering.java

@@ -12,12 +12,12 @@ public class ImperativeVsDeclarativeFiltering {
     public static void main(String[] args) {
         List<Account> accounts = Accounts.getAccountList(10);
 
-        findAllGmailAccountImperatively(accounts);
-        findAllGmailAccountDeclaratively(accounts);
+        findAllGmailAccountsImperatively(accounts);
+        findAllGmailAccountsDeclaratively(accounts);
 
     }
 
-    private static List<Account> findAllGmailAccountImperatively(List<Account> accounts) {
+    private static List<Account> findAllGmailAccountsImperatively(List<Account> accounts) {
         List<Account> gmailAccounts = new ArrayList<>();
         for (Account account : accounts) {
             if (account.getEmail().endsWith("@gmail.com")) {
@@ -27,9 +27,9 @@ private static List<Account> findAllGmailAccountImperatively(List<Account> accou
         return gmailAccounts;
     }
 
-    private static void findAllGmailAccountDeclaratively(List<Account> accounts) {
-        accounts.stream()
-                .filter(a -> a.getEmail().endsWith("@gmail"))
+    private static List<Account> findAllGmailAccountsDeclaratively(List<Account> accounts) {
+        return accounts.stream()
+                .filter(a -> a.getEmail().endsWith("@gmail.com"))
                 .collect(toList());
     }
 

stream-api/src/main/java/com/bobocode/StreamParallelProcessing.java

@@ -5,17 +5,22 @@
 import java.util.stream.LongStream;
 
 public class StreamParallelProcessing {
-    static final long STREAM_SIZE = 10_0000_000;
+    static final long STREAM_SIZE = 100_000_000;
     static final int N = 10;
 
     public static void main(String[] args) {
-        LongPredicate isEven = n -> n % 2 == 0;
+        LongPredicate isDivisibleBySeven = n -> n % 7 == 0;
 
         System.out.println("Sequential processing");
-        performNTimes(N, () -> LongStream.range(1, STREAM_SIZE).filter(isEven).count());
+        performNTimes(N, () -> LongStream.range(1, STREAM_SIZE)
+                .filter(isDivisibleBySeven)
+                .count());
 
         System.out.println("\nParallel processing");
-        performNTimes(N, () -> LongStream.range(1, STREAM_SIZE).parallel().filter(isEven).count());
+        performNTimes(N, () -> LongStream.range(1, STREAM_SIZE)
+                .parallel()
+                .filter(isDivisibleBySeven)
+                .count());
 
     }
 

stream-api/src/main/java/com/bobocode/StreamWhileExample.java

@@ -0,0 +1,39 @@
+package com.bobocode;
+
+import com.bobocode.data.Accounts;
+import com.bobocode.model.Account;
+
+import java.util.List;
+
+public class StreamWhileExample {
+    public static void main(String[] args) {
+        List<Account> accounts = Accounts.getAccountList(10);
+
+        printAllEmails(accounts);
+        printAllEmailsWhileGmail(accounts);
+        printAllEmailsWhileNotGmail(accounts);
+    }
+
+    private static void printAllEmails(List<Account> accounts) {
+        System.out.println("Whole emails list:");
+        accounts.stream()
+                .map(Account::getEmail)
+                .forEach(System.out::println);
+    }
+
+    private static void printAllEmailsWhileGmail(List<Account> accounts) {
+        System.out.println("\nAll while gmail:");
+        accounts.stream()
+                .takeWhile(a -> a.getEmail().endsWith("@gmail.com"))
+                .map(Account::getEmail)
+                .forEach(System.out::println);
+    }
+
+    private static void printAllEmailsWhileNotGmail(List<Account> accounts) {
+        System.out.println("\nAll while not gmail:");
+        accounts.stream()
+                .dropWhile(a -> a.getEmail().endsWith("@gmail.com"))
+                .map(Account::getEmail)
+                .forEach(System.out::println);
+    }
+}