Java examples for Lambda Stream:For Each
Java Print names of male members, forEach operation
import java.lang.Iterable; import java.lang.Number; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import java.util.function.BinaryOperator; import java.util.function.Consumer; import java.util.function.Function; import java.util.function.Predicate; import java.time.chrono.IsoChronology; import java.time.LocalDate; import java.time.temporal.ChronoUnit; import java.time.Period; public class BulkDataOperationsExamples { public static void main(String... args) { // w w w . jav a 2 s . c o m // Create sample data List<Person> roster = Person.createRoster(); // 1. Print names of members, for-each loop System.out.println("Members of the collection (for-each loop):"); for (Person p : roster) { System.out.println(p.getName()); } // 3. Print names of male members, forEach operation System.out.println( "Male members of the collection (bulk data operations):"); roster .stream() .filter(e -> e.getGender() == Person.Sex.MALE) .forEach(e -> System.out.println(e.getName())); // 4. Print names of male members, for-each loop System.out.println("Male members of the collection (for-each loop):"); for (Person p : roster) { if (p.getGender() == Person.Sex.MALE) { System.out.println(p.getName()); } } } } class Person { public enum Sex { MALE, FEMALE } String name; LocalDate birthday; Sex gender; String emailAddress; Person(String nameArg, LocalDate birthdayArg, Sex genderArg, String emailArg) { name = nameArg; birthday = birthdayArg; gender = genderArg; emailAddress = emailArg; } public int getAge() { return birthday.until(IsoChronology.INSTANCE.dateNow()).getYears(); } public void printPerson() { System.out.println(name + ", " + this.getAge()); } public Sex getGender() { return gender; } public String getName() { return name; } public String getEmailAddress() { return emailAddress; } public LocalDate getBirthday() { return birthday; } public static int compareByAge(Person a, Person b) { return a.birthday.compareTo(b.birthday); } public static List<Person> createRoster() { List<Person> roster = new ArrayList<>(); roster.add(new Person("Fred", IsoChronology.INSTANCE.date(1980, 6, 20), Person.Sex.MALE, "fred@example.com")); roster.add(new Person("Jane", IsoChronology.INSTANCE.date(1990, 7, 15), Person.Sex.FEMALE, "jane@example.com")); roster.add(new Person("George", IsoChronology.INSTANCE.date(1991, 8, 13), Person.Sex.MALE, "george@example.com")); roster.add(new Person("Bob", IsoChronology.INSTANCE.date(2000, 9, 12), Person.Sex.MALE, "bob@example.com")); return roster; } } /* * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of Oracle or the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */