geroza
2018-11-10 11:13:04 -02:00
parent 55c49b25f1
commit 7249a2c88d
44 changed files with 572 additions and 0 deletions
@@ -1,21 +0,0 @@
package com.baeldung.array;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;
public class ArrayBenchmarkRunner {
public static void main(String[] args) throws Exception {
Options options = new OptionsBuilder()
.include(SearchArrayUnitTest.class.getSimpleName()).threads(1)
.forks(1).shouldFailOnError(true).shouldDoGC(true)
.jvmArgs("-server").build();
new Runner(options).run();
}
}
@@ -1,78 +0,0 @@
package com.baeldung.array;
import java.util.Arrays;
import org.apache.commons.lang.ArrayUtils;
public class ArrayInitializer {
static int[] initializeArrayInLoop() {
int array[] = new int[5];
for (int i = 0; i < array.length; i++) {
array[i] = i + 2;
}
return array;
}
static int[][] initializeMultiDimensionalArrayInLoop() {
int array[][] = new int[2][5];
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 5; j++) {
array[i][j] = j + 1;
}
}
return array;
}
static String[] initializeArrayAtTimeOfDeclarationMethod1() {
String array[] = new String[] { "Toyota", "Mercedes", "BMW", "Volkswagen", "Skoda" };
return array;
}
static int[] initializeArrayAtTimeOfDeclarationMethod2() {
int[] array = new int[] { 1, 2, 3, 4, 5 };
return array;
}
static int[] initializeArrayAtTimeOfDeclarationMethod3() {
int array[] = { 1, 2, 3, 4, 5 };
return array;
}
static long[] initializeArrayUsingArraysFill() {
long array[] = new long[5];
Arrays.fill(array, 30);
return array;
}
static int[] initializeArrayRangeUsingArraysFill() {
int array[] = new int[5];
Arrays.fill(array, 0, 3, -50);
return array;
}
static int[] initializeArrayUsingArraysCopy() {
int array[] = { 1, 2, 3, 4, 5 };
int[] copy = Arrays.copyOf(array, 5);
return copy;
}
static int[] initializeLargerArrayUsingArraysCopy() {
int array[] = { 1, 2, 3, 4, 5 };
int[] copy = Arrays.copyOf(array, 6);
return copy;
}
static int[] initializeArrayUsingArraysSetAll() {
int[] array = new int[20];
Arrays.setAll(array, p -> p > 9 ? 0 : p);
return array;
}
static char[] initializeArrayUsingArraysUtilClone() {
char[] array = new char[] { 'a', 'b', 'c' };
return ArrayUtils.clone(array);
}
}
@@ -1,43 +0,0 @@
package com.baeldung.array;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.stream.IntStream;
import org.apache.commons.lang3.ArrayUtils;
import com.google.common.collect.Lists;
public class ArrayInverter {
public void invertUsingFor(Object[] array) {
for (int i = 0; i < array.length / 2; i++) {
Object temp = array[i];
array[i] = array[array.length - 1 - i];
array[array.length - 1 - i] = temp;
}
}
public void invertUsingCollectionsReverse(Object[] array) {
List<Object> list = Arrays.asList(array);
Collections.reverse(list);
}
public Object[] invertUsingStreams(final Object[] array) {
return IntStream.rangeClosed(1, array.length)
.mapToObj(i -> array[array.length - i])
.toArray();
}
public void invertUsingCommonsLang(Object[] array) {
ArrayUtils.reverse(array);
}
public Object[] invertUsingGuava(Object[] array) {
List<Object> list = Arrays.asList(array);
List<Object> reverted = Lists.reverse(list);
return reverted.toArray();
}
}
@@ -1,159 +0,0 @@
package com.baeldung.array;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.List;
import java.util.stream.IntStream;
import java.util.stream.Stream;
public class ArrayReferenceGuide {
public static void main(String[] args) {
declaration();
initialization();
access();
iterating();
varargs();
transformIntoList();
transformIntoStream();
sort();
search();
merge();
}
private static void declaration() {
int[] anArray;
int anotherArray[];
}
private static void initialization() {
int[] anArray = new int[10];
anArray[0] = 10;
anArray[5] = 4;
int[] anotherArray = new int[] {1, 2, 3, 4, 5};
}
private static void access() {
int[] anArray = new int[10];
anArray[0] = 10;
anArray[5] = 4;
System.out.println(anArray[0]);
}
private static void iterating() {
int[] anArray = new int[] {1, 2, 3, 4, 5};
for (int i = 0; i < anArray.length; i++) {
System.out.println(anArray[i]);
}
for (int element : anArray) {
System.out.println(element);
}
}
private static void varargs() {
String[] groceries = new String[] {"Milk", "Tomato", "Chips"};
varargMethod(groceries);
varargMethod("Milk", "Tomato", "Chips");
}
private static void varargMethod(String... varargs) {
for (String element : varargs) {
System.out.println(element);
}
}
private static void transformIntoList() {
Integer[] anArray = new Integer[] {1, 2, 3, 4, 5};
// Naïve implementation
List<Integer> aList = new ArrayList<>(); // We create an empty list
for (int element : anArray) {
// We iterate over array's elements and add them to the list
aList.add(element);
}
// Pretty implementation
aList = Arrays.asList(anArray);
// Drawbacks
try {
aList.remove(0);
} catch (UnsupportedOperationException e) {
System.out.println(e.getMessage());
}
try {
aList.add(6);
} catch (UnsupportedOperationException e) {
System.out.println(e.getMessage());
}
int[] anotherArray = new int[] {1, 2, 3, 4, 5};
// List<Integer> anotherList = Arrays.asList(anotherArray);
}
private static void transformIntoStream() {
int[] anArray = new int[] {1, 2, 3, 4, 5};
IntStream aStream = Arrays.stream(anArray);
Integer[] anotherArray = new Integer[] {1, 2, 3, 4, 5};
Stream<Integer> anotherStream = Arrays.stream(anotherArray, 2, 4);
}
private static void sort() {
int[] anArray = new int[] {5, 2, 1, 4, 8};
Arrays.sort(anArray); // anArray is now {1, 2, 4, 5, 8}
Integer[] anotherArray = new Integer[] {5, 2, 1, 4, 8};
Arrays.sort(anotherArray); // anArray is now {1, 2, 4, 5, 8}
String[] yetAnotherArray = new String[] {"A", "E", "Z", "B", "C"};
Arrays.sort(yetAnotherArray, 1, 3, Comparator.comparing(String::toString).reversed()); // yetAnotherArray is now {"A", "Z", "E", "B", "C"}
}
private static void search() {
int[] anArray = new int[] {5, 2, 1, 4, 8};
for (int i = 0; i < anArray.length; i++) {
if (anArray[i] == 4) {
System.out.println("Found at index " + i);
break;
}
}
Arrays.sort(anArray);
int index = Arrays.binarySearch(anArray, 4);
System.out.println("Found at index " + index);
}
private static void merge() {
int[] anArray = new int[] {5, 2, 1, 4, 8};
int[] anotherArray = new int[] {10, 4, 9, 11, 2};
int[] resultArray = new int[anArray.length + anotherArray.length];
for (int i = 0; i < resultArray.length; i++) {
resultArray[i] = (i < anArray.length ? anArray[i] : anotherArray[i - anArray.length]);
}
for (int element : resultArray) {
System.out.println(element);
}
Arrays.setAll(resultArray, i -> (i < anArray.length ? anArray[i] : anotherArray[i - anArray.length]));
for (int element : resultArray) {
System.out.println(element);
}
}
}
@@ -1,20 +0,0 @@
package com.baeldung.array;
public class Find2ndLargestInArray {
public static int find2ndLargestElement(int[] array) {
int maxElement = array[0];
int secondLargestElement = -1;
for (int index = 0; index < array.length; index++) {
if (maxElement <= array[index]) {
secondLargestElement = maxElement;
maxElement = array[index];
} else if (secondLargestElement < array[index]) {
secondLargestElement = array[index];
}
}
return secondLargestElement;
}
}
@@ -1,22 +0,0 @@
package com.baeldung.array;
import java.util.Arrays;
public class FindElementInArray {
public static boolean findGivenElementInArrayWithoutUsingStream(int[] array, int element) {
boolean actualResult = false;
for (int index = 0; index < array.length; index++) {
if (element == array[index]) {
actualResult = true;
break;
}
}
return actualResult;
}
public static boolean findGivenElementInArrayUsingStream(int[] array, int element) {
return Arrays.stream(array).filter(x -> element == x).findFirst().isPresent();
}
}
@@ -1,49 +0,0 @@
package com.baeldung.array;
import java.util.Arrays;
import java.util.Scanner;
public class JaggedArray {
int[][] shortHandFormInitialization() {
int[][] jaggedArr = { { 1, 2 }, { 3, 4, 5 }, { 6, 7, 8, 9 } };
return jaggedArr;
}
int[][] declarationAndThenInitialization() {
int[][] jaggedArr = new int[3][];
jaggedArr[0] = new int[] { 1, 2 };
jaggedArr[1] = new int[] { 3, 4, 5 };
jaggedArr[2] = new int[] { 6, 7, 8, 9 };
return jaggedArr;
}
int[][] declarationAndThenInitializationUsingUserInputs() {
int[][] jaggedArr = new int[3][];
jaggedArr[0] = new int[2];
jaggedArr[1] = new int[3];
jaggedArr[2] = new int[4];
initializeElements(jaggedArr);
return jaggedArr;
}
void initializeElements(int[][] jaggedArr) {
Scanner sc = new Scanner(System.in);
for (int outer = 0; outer < jaggedArr.length; outer++) {
for (int inner = 0; inner < jaggedArr[outer].length; inner++) {
jaggedArr[outer][inner] = sc.nextInt();
}
}
}
void printElements(int[][] jaggedArr) {
for (int index = 0; index < jaggedArr.length; index++) {
System.out.println(Arrays.toString(jaggedArr[index]));
}
}
int[] getElementAtGivenIndex(int[][] jaggedArr, int index) {
return jaggedArr[index];
}
}
@@ -1,96 +0,0 @@
package com.baeldung.array;
import org.openjdk.jmh.annotations.*;
import java.util.*;
import java.util.concurrent.TimeUnit;
@BenchmarkMode(Mode.AverageTime)
@Warmup(iterations = 5)
@OutputTimeUnit(TimeUnit.MICROSECONDS)
public class SearchArrayUnitTest {
@State(Scope.Benchmark)
public static class SearchData {
static int count = 1000;
static String[] strings = seedArray(1000);
}
@Benchmark
public void searchArrayLoop() {
for (int i = 0; i < SearchData.count; i++) {
searchLoop(SearchData.strings, "T");
}
}
@Benchmark
public void searchArrayAllocNewList() {
for (int i = 0; i < SearchData.count; i++) {
searchList(SearchData.strings, "T");
}
}
@Benchmark
public void searchArrayAllocNewSet() {
for (int i = 0; i < SearchData.count; i++) {
searchSet(SearchData.strings, "T");
}
}
@Benchmark
public void searchArrayReuseList() {
List<String> asList = Arrays.asList(SearchData.strings);
for (int i = 0; i < SearchData.count; i++) {
asList.contains("T");
}
}
@Benchmark
public void searchArrayReuseSet() {
Set<String> asSet = new HashSet<>(Arrays.asList(SearchData.strings));
for (int i = 0; i < SearchData.count; i++) {
asSet.contains("T");
}
}
@Benchmark
public void searchArrayBinarySearch() {
Arrays.sort(SearchData.strings);
for (int i = 0; i < SearchData.count; i++) {
Arrays.binarySearch(SearchData.strings, "T");
}
}
private boolean searchList(String[] strings, String searchString) {
return Arrays.asList(strings).contains(searchString);
}
private boolean searchSet(String[] strings, String searchString) {
Set<String> set = new HashSet<>(Arrays.asList(strings));
return set.contains(searchString);
}
private boolean searchLoop(String[] strings, String searchString) {
for (String s : strings) {
if (s.equals(searchString))
return true;
}
return false;
}
private static String[] seedArray(int length) {
String[] strings = new String[length];
Random random = new Random();
for (int i = 0; i < length; i++)
{
strings[i] = String.valueOf(random.nextInt());
}
return strings;
}
}
@@ -1,31 +0,0 @@
package com.baeldung.array;
import java.util.Arrays;
public class SumAndAverageInArray {
public static int findSumWithoutUsingStream(int[] array) {
int sum = 0;
for (int value : array) {
sum += value;
}
return sum;
}
public static int findSumUsingStream(int[] array) {
return Arrays.stream(array).sum();
}
public static int findSumUsingStream(Integer[] array) {
return Arrays.stream(array).mapToInt(Integer::intValue).sum();
}
public static double findAverageWithoutUsingStream(int[] array) {
int sum = findSumWithoutUsingStream(array);
return (double) sum / array.length;
}
public static double findAverageUsingStream(int[] array) {
return Arrays.stream(array).average().orElse(Double.NaN);
}
}
@@ -1,61 +0,0 @@
package com.baeldung.arraycopy.model;
public class Address implements Cloneable {
private String country;
private String state;
private String city;
private String street;
private String zipcode;
public String getCountry() {
return country;
}
public void setCountry(String country) {
this.country = country;
}
public String getState() {
return state;
}
public void setState(String state) {
this.state = state;
}
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public String getStreet() {
return street;
}
public void setStreet(String street) {
this.street = street;
}
public String getZipcode() {
return zipcode;
}
public void setZipcode(String zipcode) {
this.zipcode = zipcode;
}
@Override
protected Object clone() throws CloneNotSupportedException {
super.clone();
Address address = new Address();
address.setCity(this.city);
address.setCountry(this.country);
address.setState(this.state);
address.setStreet(this.street);
address.setZipcode(this.zipcode);
return address;
}
}
@@ -1,25 +0,0 @@
package com.baeldung.arraycopy.model;
import java.io.Serializable;
public class Employee implements Serializable {
private static final long serialVersionUID = -2454619097207585825L;
private int id;
private String name;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
@@ -1,40 +0,0 @@
package com.baeldung.doubles;
import java.math.BigDecimal;
public class SplitFloatingPointNumbers {
public static void main(String[] args) {
double doubleNumber = 24.04;
splitUsingFloatingTypes(doubleNumber);
splitUsingString(doubleNumber);
splitUsingBigDecimal(doubleNumber);
}
private static void splitUsingFloatingTypes(double doubleNumber) {
System.out.println("Using Floating Point Arithmetics:");
int intPart = (int) doubleNumber;
System.out.println("Double Number: "+doubleNumber);
System.out.println("Integer Part: "+ intPart);
System.out.println("Decimal Part: "+ (doubleNumber - intPart));
}
private static void splitUsingString(double doubleNumber) {
System.out.println("Using String Operations:");
String doubleAsString = String.valueOf(doubleNumber);
int indexOfDecimal = doubleAsString.indexOf(".");
System.out.println("Double Number: "+doubleNumber);
System.out.println("Integer Part: "+ doubleAsString.substring(0, indexOfDecimal));
System.out.println("Decimal Part: "+ doubleAsString.substring(indexOfDecimal));
}
private static void splitUsingBigDecimal(double doubleNumber) {
System.out.println("Using BigDecimal Operations:");
BigDecimal bigDecimal = new BigDecimal(String.valueOf(doubleNumber));
int intValue = bigDecimal.intValue();
System.out.println("Double Number: "+bigDecimal.toPlainString());
System.out.println("Integer Part: "+intValue);
System.out.println("Decimal Part: "+bigDecimal.subtract(new BigDecimal(intValue)).toPlainString());
}
}
@@ -1,27 +0,0 @@
package com.baeldung.inheritancecomposition.application;
import com.baeldung.inheritancecomposition.model.Actress;
import com.baeldung.inheritancecomposition.model.Computer;
import com.baeldung.inheritancecomposition.model.StandardMemory;
import com.baeldung.inheritancecomposition.model.Person;
import com.baeldung.inheritancecomposition.model.StandardProcessor;
import com.baeldung.inheritancecomposition.model.StandardSoundCard;
import com.baeldung.inheritancecomposition.model.Waitress;
public class Application {
public static void main(String[] args) {
Person person = new Person("John", "john@domain.com", 35);
Waitress waitress = new Waitress("Mary", "mary@domain.com", 22);
System.out.println(waitress.serveStarter("mixed salad"));
System.out.println(waitress.serveMainCourse("steak"));
System.out.println(waitress.serveDessert("cup of cofee"));
Actress actress = new Actress("Susan", "susan@domain.com", 30);
System.out.println(actress.readScript("Psycho"));
System.out.println(actress.performRole());
Computer computer = new Computer(new StandardProcessor("Intel I3"), new StandardMemory("Kingston", "1TB"));
computer.setSoundCard(new StandardSoundCard("Generic Sound Card"));
System.out.println(computer);
}
}
@@ -1,16 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public class Actress extends Person {
public Actress(String name, String email, int age) {
super(name, email, age);
}
public String readScript(String movie) {
return "Reading the script of " + movie;
}
public String performRole() {
return "Performing a role";
}
}
@@ -1,36 +0,0 @@
package com.baeldung.inheritancecomposition.model;
import java.util.Optional;
public class Computer {
private Processor processor;
private Memory memory;
private SoundCard soundCard;
public Computer(Processor processor, Memory memory) {
this.processor = processor;
this.memory = memory;
}
public void setSoundCard(SoundCard soundCard) {
this.soundCard = soundCard;
}
public Processor getProcessor() {
return processor;
}
public Memory getMemory() {
return memory;
}
public Optional<SoundCard> getSoundCard() {
return Optional.ofNullable(soundCard);
}
@Override
public String toString() {
return "Computer{" + "processor=" + processor + ", memory=" + memory + ", soundcard=" + soundCard +"}";
}
}
@@ -1,8 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public interface Memory {
String getBrand();
String getSize();
}
@@ -1,31 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public class Person {
private final String name;
private final String email;
private final int age;
public Person(String name, String email, int age) {
this.name = name;
this.email = email;
this.age = age;
}
public String getName() {
return name;
}
public String getEmail() {
return email;
}
public int getAge() {
return age;
}
@Override
public String toString() {
return "Person{" + "name=" + name + ", email=" + email + ", age=" + age + "}";
}
}
@@ -1,6 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public interface Processor {
String getModel();
}
@@ -1,6 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public interface SoundCard {
String getBrand();
}
@@ -1,25 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public class StandardMemory implements Memory {
private String brand;
private String size;
public StandardMemory(String brand, String size) {
this.brand = brand;
this.size = size;
}
public String getBrand() {
return brand;
}
public String getSize() {
return size;
}
@Override
public String toString() {
return "Memory{" + "brand=" + brand + ", size=" + size + "}";
}
}
@@ -1,20 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public class StandardProcessor implements Processor {
private String model;
public StandardProcessor(String model) {
this.model = model;
}
@Override
public String getModel() {
return model;
}
@Override
public String toString() {
return "Processor{" + "model=" + model + "}";
}
}
@@ -1,20 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public class StandardSoundCard implements SoundCard {
private String brand;
public StandardSoundCard(String brand) {
this.brand = brand;
}
@Override
public String getBrand() {
return brand;
}
@Override
public String toString() {
return "SoundCard{" + "brand=" + brand + "}";
}
}
@@ -1,20 +0,0 @@
package com.baeldung.inheritancecomposition.model;
public class Waitress extends Person {
public Waitress(String name, String email, int age) {
super(name, email, age);
}
public String serveStarter(String starter) {
return "Serving a " + starter;
}
public String serveMainCourse(String mainCourse) {
return "Serving a " + mainCourse;
}
public String serveDessert(String dessert) {
return "Serving a " + dessert;
}
}
@@ -1,23 +0,0 @@
package com.baeldung.sneakythrows;
import lombok.SneakyThrows;
public class SneakyRunnable implements Runnable {
@SneakyThrows
public void run() {
try {
throw new InterruptedException();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
try {
new SneakyRunnable().run();
} catch (Exception e) {
e.printStackTrace();
}
}
}
@@ -1,25 +0,0 @@
package com.baeldung.sneakythrows;
import java.io.IOException;
public class SneakyThrows {
public static <E extends Throwable> void sneakyThrow(Throwable e) throws E {
throw (E) e;
}
public static void throwsSneakyIOException() {
sneakyThrow(new IOException("sneaky"));
}
public static void main(String[] args) {
try {
throwsSneakyIOException();
} catch (Exception ex) {
ex.printStackTrace();
}
}
}