parallel stream example

Author: basahota

parralel_stream/ParallelStreamExample.java

@@ -0,0 +1,56 @@
+package com.javatechie.parralel_stream;
+
+import com.javatechie.map_reduce.Employee;
+import com.javatechie.map_reduce.EmployeeDatabase;
+
+import java.util.List;
+import java.util.stream.IntStream;
+
+public class ParallelStreamExample {
+
+
+    public static void main(String[] args) {
+        long start=0;
+        long end=0;
+
+        start=System.currentTimeMillis();
+        IntStream.range(1,100).forEach(System.out::println);
+        end=System.currentTimeMillis();
+        System.out.println("Plain stream took time : "+(end-start));
+
+       System.out.println("============================================");
+
+       start=System.currentTimeMillis();
+       IntStream.range(1,100).parallel().forEach(System.out::println);
+        end=System.currentTimeMillis();
+        System.out.println("Parallel stream took time : "+(end-start));
+
+
+
+        IntStream.range(1,10).forEach(x->{
+            System.out.println("Thread : "+Thread.currentThread().getName()+" : "+x);
+        });
+
+        IntStream.range(1,10).parallel().forEach(x->{
+            System.out.println("Thread : "+Thread.currentThread().getName()+" : "+x);
+        });
+
+        List<Employee> employees = EmployeeDatabase.getEmployees();
+
+        //normal
+        start=System.currentTimeMillis();
+        double salaryWithStream = employees.stream()
+                .map(Employee::getSalary).mapToDouble(i -> i).average().getAsDouble();
+        end=System.currentTimeMillis();
+
+        System.out.println("Normal stream execution time : "+(end-start)+" : Avg salary : "+salaryWithStream);
+
+        start=System.currentTimeMillis();
+        double salaryWithParallelStream = employees.parallelStream()
+                .map(Employee::getSalary).mapToDouble(i -> i).average().getAsDouble();
+
+        end=System.currentTimeMillis();
+
+        System.out.println("Parallel stream execution time : "+(end-start)+" : Avg salary : "+salaryWithParallelStream);
+    }
+}