core-java-collections-3 模块添加到仓库列表中
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core-java-modules/core-java-collections-3/README.md
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core-java-modules/core-java-collections-3/README.md
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=========
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## Core Java Collections Cookbooks and Examples
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### Relevant Articles:
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- [Time Comparison of Arrays.sort(Object[]) and Arrays.sort(int[])](https://www.baeldung.com/arrays-sortobject-vs-sortint)
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- [Java ArrayList vs Vector](https://www.baeldung.com/java-arraylist-vs-vector)
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- [Differences Between HashMap and Hashtable](https://www.baeldung.com/hashmap-hashtable-differences)
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- [Differences Between Collection.clear() and Collection.removeAll()](https://www.baeldung.com/java-collection-clear-vs-removeall)
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- [Performance of contains() in a HashSet vs ArrayList](https://www.baeldung.com/java-hashset-arraylist-contains-performance)
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- [Fail-Safe Iterator vs Fail-Fast Iterator](https://www.baeldung.com/java-fail-safe-vs-fail-fast-iterator)
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- [Quick Guide to the Java Stack](https://www.baeldung.com/java-stack)
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- [A Guide to BitSet in Java](https://www.baeldung.com/java-bitset)
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- [Get the First Key and Value From a HashMap](https://www.baeldung.com/java-hashmap-get-first-entry)
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- [Performance of removeAll() in a HashSet](https://www.baeldung.com/java-hashset-removeall-performance)
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- More articles: [[<-- prev]](/core-java-modules/core-java-collections-2) [[next -->]](/core-java-modules/core-java-collections-4)
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core-java-modules/core-java-collections-3/pom.xml
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core-java-modules/core-java-collections-3/pom.xml
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<?xml version="1.0" encoding="UTF-8"?>
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<project xmlns="http://maven.apache.org/POM/4.0.0"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
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<modelVersion>4.0.0</modelVersion>
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<artifactId>core-java-collections-3</artifactId>
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<version>0.1.0-SNAPSHOT</version>
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<name>core-java-collections-3</name>
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<packaging>jar</packaging>
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<parent>
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<groupId>com.ossez.core-java-modules</groupId>
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<artifactId>core-java-modules</artifactId>
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<version>0.0.2-SNAPSHOT</version>
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<relativePath>../pom.xml</relativePath>
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</parent>
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<dependencies>
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<dependency>
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<groupId>org.openjdk.jol</groupId>
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<artifactId>jol-core</artifactId>
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<version>${jol-core.version}</version>
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</dependency>
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<dependency>
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<groupId>org.openjdk.jmh</groupId>
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<artifactId>jmh-core</artifactId>
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<version>${jmh-core.version}</version>
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</dependency>
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<dependency>
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<groupId>org.apache.commons</groupId>
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<artifactId>commons-lang3</artifactId>
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<version>${commons-lang3.version}</version>
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</dependency>
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</dependencies>
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<properties>
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<jol-core.version>0.10</jol-core.version>
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</properties>
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</project>
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package com.ossez.collections.collections.arraylistvsvector;
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import org.openjdk.jmh.annotations.*;
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import org.openjdk.jmh.runner.Runner;
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import org.openjdk.jmh.runner.options.Options;
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import org.openjdk.jmh.runner.options.OptionsBuilder;
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import java.util.*;
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import java.util.concurrent.TimeUnit;
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(TimeUnit.NANOSECONDS)
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@Warmup(iterations = 10)
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public class ArrayListBenchmark {
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@State(Scope.Thread)
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public static class MyState {
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List<Employee> employeeList = new ArrayList<>();
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Vector<Employee> employeeVector = new Vector<>();
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//LinkedList<Employee> employeeList = new LinkedList<>();
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long iterations = 100000;
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Employee employee = new Employee(100L, "Harry");
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int employeeIndex = -1;
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@Setup(Level.Trial)
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public void setUp() {
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for (long i = 0; i < iterations; i++) {
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employeeList.add(new Employee(i, "John"));
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employeeVector.add(new Employee(i, "John"));
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}
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employeeList.add(employee);
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employeeVector.add(employee);
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employeeIndex = employeeList.indexOf(employee);
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}
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}
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@Benchmark
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public void testAddAt(ArrayListBenchmark.MyState state) {
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state.employeeList.add((int) (state.iterations), new Employee(state.iterations, "John"));
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}
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@Benchmark
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public boolean testContains(ArrayListBenchmark.MyState state) {
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return state.employeeList.contains(state.employee);
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}
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@Benchmark
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public boolean testContainsVector(ArrayListBenchmark.MyState state) {
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return state.employeeVector.contains(state.employee);
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}
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@Benchmark
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public int testIndexOf(ArrayListBenchmark.MyState state) {
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return state.employeeList.indexOf(state.employee);
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}
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@Benchmark
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public Employee testGet(ArrayListBenchmark.MyState state) {
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return state.employeeList.get(state.employeeIndex);
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}
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@Benchmark
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public Employee testVectorGet(ArrayListBenchmark.MyState state) {
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return state.employeeVector.get(state.employeeIndex);
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}
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@Benchmark
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public boolean testRemove(ArrayListBenchmark.MyState state) {
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return state.employeeList.remove(state.employee);
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}
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@Benchmark
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public void testAdd(ArrayListBenchmark.MyState state) {
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state.employeeList.add(new Employee(state.iterations + 1, "John"));
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}
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public static void main(String[] args) throws Exception {
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Options options = new OptionsBuilder()
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.include(ArrayListBenchmark.class.getSimpleName()).threads(3)
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.forks(1).shouldFailOnError(true)
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.shouldDoGC(true)
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.jvmArgs("-server").build();
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new Runner(options).run();
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}
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}
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package com.ossez.collections.collections.arraylistvsvector;
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public class Employee {
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private Long id;
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private String name;
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public Employee(Long id, String name) {
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this.name = name;
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this.id = id;
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}
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public Long getId() {
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return id;
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}
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public void setId(Long id) {
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this.id = id;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) return true;
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if (o == null || getClass() != o.getClass()) return false;
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Employee employee = (Employee) o;
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if (!id.equals(employee.id)) return false;
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return name.equals(employee.name);
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}
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@Override
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public int hashCode() {
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int result = id.hashCode();
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result = 31 * result + name.hashCode();
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return result;
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}
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@Override
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public String toString() {
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return "Employee{" +
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"id=" + id +
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", name='" + name + '\'' +
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'}';
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}
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}
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package com.ossez.collections.collections.arraylistvsvector;
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import java.util.Enumeration;
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import java.util.Iterator;
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import java.util.Vector;
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public class VectorExample {
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public static void main(String[] args) {
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Vector<String> vector = new Vector<>();
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vector.add("baeldung");
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vector.add("Vector");
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vector.add("example");
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Enumeration e = vector.elements();
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while(e.hasMoreElements()){
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System.out.println(e.nextElement());
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}
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Iterator<String> iterator = vector.iterator();
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while (iterator.hasNext()) {
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System.out.println(iterator.next());
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}
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}
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}
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package com.ossez.collections.collections.containsperformance;
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import org.openjdk.jmh.annotations.*;
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import org.openjdk.jmh.runner.Runner;
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import org.openjdk.jmh.runner.options.Options;
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import org.openjdk.jmh.runner.options.OptionsBuilder;
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import java.util.ArrayList;
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import java.util.HashSet;
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import java.util.List;
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import java.util.Set;
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import java.util.concurrent.TimeUnit;
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(TimeUnit.NANOSECONDS)
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@Warmup(iterations = 5)
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public class CollectionsBenchmark {
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@State(Scope.Thread)
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public static class MyState {
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private Set<Employee> employeeSet = new HashSet<>();
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private List<Employee> employeeList = new ArrayList<>();
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private long iterations = 10000;
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private Employee employee = new Employee(100L, "Harry");
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@Setup(Level.Trial)
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public void setUp() {
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for (long i = 0; i < iterations; i++) {
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employeeSet.add(new Employee(i, "John"));
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employeeList.add(new Employee(i, "John"));
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}
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employeeList.add(employee);
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employeeSet.add(employee);
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}
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}
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@Benchmark
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public boolean testArrayList(MyState state) {
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return state.employeeList.contains(state.employee);
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}
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@Benchmark
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public boolean testHashSet(MyState state) {
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return state.employeeSet.contains(state.employee);
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}
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public static void main(String[] args) throws Exception {
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Options options = new OptionsBuilder()
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.include(CollectionsBenchmark.class.getSimpleName()).threads(1)
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.forks(1).shouldFailOnError(true)
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.shouldDoGC(true)
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.jvmArgs("-server").build();
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new Runner(options).run();
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}
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}
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package com.ossez.collections.collections.containsperformance;
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public class Employee {
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private Long id;
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private String name;
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public Employee(Long id, String name) {
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this.name = name;
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this.id = id;
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}
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public Long getId() {
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return id;
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}
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public void setId(Long id) {
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this.id = id;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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@Override
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public boolean equals(Object o) {
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if (this == o) return true;
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if (o == null || getClass() != o.getClass()) return false;
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Employee employee = (Employee) o;
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if (!id.equals(employee.id)) return false;
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return name.equals(employee.name);
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}
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@Override
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public int hashCode() {
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int result = id.hashCode();
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result = 31 * result + name.hashCode();
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return result;
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}
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@Override
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public String toString() {
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return "Employee{" +
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"id=" + id +
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", name='" + name + '\'' +
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'}';
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}
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}
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package com.ossez.collections.collections.iterators;
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import org.slf4j.Logger;
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import org.slf4j.LoggerFactory;
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import java.util.ArrayList;
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import java.util.Iterator;
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import java.util.concurrent.ConcurrentHashMap;
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public class Iterators {
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private static final Logger LOG = LoggerFactory.getLogger(Iterators.class);
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public static int failFast1() {
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ArrayList<Integer> numbers = new ArrayList<>();
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numbers.add(10);
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numbers.add(20);
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numbers.add(30);
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numbers.add(40);
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Iterator<Integer> iterator = numbers.iterator();
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while (iterator.hasNext()) {
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Integer number = iterator.next();
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numbers.add(50);
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}
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return numbers.size();
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}
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public static int failFast2() {
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ArrayList<Integer> numbers = new ArrayList<>();
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numbers.add(10);
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numbers.add(20);
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numbers.add(30);
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numbers.add(40);
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Iterator<Integer> iterator = numbers.iterator();
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while (iterator.hasNext()) {
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if (iterator.next() == 30) {
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// will not throw Exception
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iterator.remove();
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}
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}
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LOG.debug("using iterator's remove method = {}", numbers);
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iterator = numbers.iterator();
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while (iterator.hasNext()) {
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if (iterator.next() == 40) {
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// will throw Exception on
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// next call of next() method
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numbers.remove(2);
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}
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}
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return numbers.size();
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}
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public static int failSafe1() {
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ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<>();
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map.put("First", 10);
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map.put("Second", 20);
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map.put("Third", 30);
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map.put("Fourth", 40);
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Iterator<String> iterator = map.keySet()
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.iterator();
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while (iterator.hasNext()) {
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String key = iterator.next();
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map.put("Fifth", 50);
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}
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return map.size();
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}
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}
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package com.ossez.collections.collections.removeallperformance;
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import java.util.ArrayList;
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import java.util.HashSet;
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import java.util.List;
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import java.util.Set;
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import java.util.concurrent.TimeUnit;
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import com.ossez.collections.collections.containsperformance.Employee;
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import org.apache.commons.lang3.RandomStringUtils;
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import org.openjdk.jmh.annotations.Benchmark;
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import org.openjdk.jmh.annotations.BenchmarkMode;
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import org.openjdk.jmh.annotations.Level;
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import org.openjdk.jmh.annotations.Mode;
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import org.openjdk.jmh.annotations.OutputTimeUnit;
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import org.openjdk.jmh.annotations.Scope;
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import org.openjdk.jmh.annotations.Setup;
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import org.openjdk.jmh.annotations.State;
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import org.openjdk.jmh.annotations.Warmup;
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import org.openjdk.jmh.runner.Runner;
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import org.openjdk.jmh.runner.options.Options;
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import org.openjdk.jmh.runner.options.OptionsBuilder;
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@BenchmarkMode(Mode.AverageTime)
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@OutputTimeUnit(TimeUnit.NANOSECONDS)
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@Warmup(iterations = 5)
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public class HashSetBenchmark {
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@State(Scope.Thread)
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public static class MyState {
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private Set<Employee> employeeSet1 = new HashSet<>();
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private List<Employee> employeeList1 = new ArrayList<>();
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private Set<Employee> employeeSet2 = new HashSet<>();
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private List<Employee> employeeList2 = new ArrayList<>();
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private Set<Employee> employeeSet3 = new HashSet<>();
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private Set<Employee> employeeSet4 = new HashSet<>();
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private long set1Size = 60000;
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private long list1Size = 50000;
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private long set2Size = 50000;
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private long list2Size = 60000;
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private long set3Size = 50000;
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private long set4Size = 60000;
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@Setup(Level.Trial)
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public void setUp() {
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for (long i = 0; i < set1Size; i++) {
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employeeSet1.add(new Employee(i, RandomStringUtils.random(7, true, false)));
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}
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for (long i = 0; i < list1Size; i++) {
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employeeList1.add(new Employee(i, RandomStringUtils.random(7, true, false)));
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}
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for (long i = 0; i < set2Size; i++) {
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employeeSet2.add(new Employee(i, RandomStringUtils.random(7, true, false)));
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}
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for (long i = 0; i < list2Size; i++) {
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employeeList2.add(new Employee(i, RandomStringUtils.random(7, true, false)));
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}
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for (long i = 0; i < set3Size; i++) {
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employeeSet3.add(new Employee(i, RandomStringUtils.random(7, true, false)));
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}
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for (long i = 0; i < set4Size; i++) {
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employeeSet4.add(new Employee(i, RandomStringUtils.random(7, true, false)));
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}
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}
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}
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@Benchmark
|
||||
public boolean given_SizeOfHashsetGreaterThanSizeOfCollection_When_RemoveAllFromHashSet_Then_GoodPerformance(MyState state) {
|
||||
return state.employeeSet1.removeAll(state.employeeList1);
|
||||
}
|
||||
|
||||
@Benchmark
|
||||
public boolean given_SizeOfHashsetSmallerThanSizeOfCollection_When_RemoveAllFromHashSet_Then_BadPerformance(MyState state) {
|
||||
return state.employeeSet2.removeAll(state.employeeList2);
|
||||
}
|
||||
|
||||
@Benchmark
|
||||
public boolean given_SizeOfHashsetSmallerThanSizeOfAnotherHashSet_When_RemoveAllFromHashSet_Then_GoodPerformance(MyState state) {
|
||||
return state.employeeSet3.removeAll(state.employeeSet4);
|
||||
}
|
||||
|
||||
public static void main(String[] args) throws Exception {
|
||||
Options options = new OptionsBuilder().include(HashSetBenchmark.class.getSimpleName())
|
||||
.threads(1)
|
||||
.forks(1)
|
||||
.shouldFailOnError(true)
|
||||
.shouldDoGC(true)
|
||||
.jvmArgs("-server")
|
||||
.build();
|
||||
new Runner(options).run();
|
||||
}
|
||||
|
||||
}
|
||||
@ -0,0 +1,51 @@
|
||||
package com.ossez.collections.collections.sortingcomparison;
|
||||
|
||||
import java.util.Arrays;
|
||||
import java.util.concurrent.TimeUnit;
|
||||
|
||||
import org.openjdk.jmh.annotations.Benchmark;
|
||||
import org.openjdk.jmh.annotations.BenchmarkMode;
|
||||
import org.openjdk.jmh.annotations.Measurement;
|
||||
import org.openjdk.jmh.annotations.Mode;
|
||||
import org.openjdk.jmh.annotations.OutputTimeUnit;
|
||||
import org.openjdk.jmh.annotations.Scope;
|
||||
import org.openjdk.jmh.annotations.State;
|
||||
import org.openjdk.jmh.annotations.Warmup;
|
||||
import org.openjdk.jmh.runner.Runner;
|
||||
import org.openjdk.jmh.runner.options.Options;
|
||||
import org.openjdk.jmh.runner.options.OptionsBuilder;
|
||||
|
||||
@BenchmarkMode(Mode.AverageTime)
|
||||
@OutputTimeUnit(TimeUnit.MILLISECONDS)
|
||||
@Measurement(batchSize = 100000, iterations = 10)
|
||||
@Warmup(batchSize = 100000, iterations = 10)
|
||||
public class ArraySortBenchmark {
|
||||
|
||||
@State(Scope.Thread)
|
||||
public static class Initialize {
|
||||
Integer[] numbers = { -769214442, -1283881723, 1504158300, -1260321086, -1800976432, 1278262737, 1863224321, 1895424914, 2062768552, -1051922993, 751605209, -1500919212, 2094856518, -1014488489, -931226326, -1677121986, -2080561705, 562424208, -1233745158, 41308167 };
|
||||
int[] primitives = { -769214442, -1283881723, 1504158300, -1260321086, -1800976432, 1278262737, 1863224321, 1895424914, 2062768552, -1051922993, 751605209, -1500919212, 2094856518, -1014488489, -931226326, -1677121986, -2080561705, 562424208, -1233745158, 41308167 };
|
||||
}
|
||||
|
||||
@Benchmark
|
||||
public Integer[] benchmarkArraysIntegerSort(ArraySortBenchmark.Initialize state) {
|
||||
Arrays.sort(state.numbers);
|
||||
return state.numbers;
|
||||
}
|
||||
|
||||
@Benchmark
|
||||
public int[] benchmarkArraysIntSort(ArraySortBenchmark.Initialize state) {
|
||||
Arrays.sort(state.primitives);
|
||||
return state.primitives;
|
||||
}
|
||||
|
||||
|
||||
public static void main(String[] args) throws Exception {
|
||||
Options options = new OptionsBuilder()
|
||||
.include(ArraySortBenchmark.class.getSimpleName()).threads(1)
|
||||
.forks(1).shouldFailOnError(true)
|
||||
.shouldDoGC(true)
|
||||
.jvmArgs("-server").build();
|
||||
new Runner(options).run();
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,39 @@
|
||||
package com.ossez.collections.collections.sortingcomparison;
|
||||
|
||||
import java.util.ArrayList;
|
||||
import java.util.Arrays;
|
||||
import java.util.Collections;
|
||||
import java.util.List;
|
||||
|
||||
public class CollectionsSortCompare {
|
||||
|
||||
public static void main(String[] args) {
|
||||
sortPrimitives();
|
||||
sortReferenceType();
|
||||
sortCollection();
|
||||
}
|
||||
|
||||
private static void sortReferenceType() {
|
||||
Integer[] numbers = {5, 22, 10, 0};
|
||||
Arrays.sort(numbers);
|
||||
System.out.println(Arrays.toString(numbers));
|
||||
}
|
||||
|
||||
private static void sortCollection() {
|
||||
List<Integer> numbersList = new ArrayList<>();
|
||||
numbersList.add(5);
|
||||
numbersList.add(22);
|
||||
numbersList.add(10);
|
||||
numbersList.add(0);
|
||||
|
||||
Collections.sort(numbersList);
|
||||
|
||||
numbersList.forEach(System.out::print);
|
||||
}
|
||||
|
||||
private static void sortPrimitives() {
|
||||
int[] numbers = {5, 22, 10, 0};
|
||||
Arrays.sort(numbers);
|
||||
System.out.println(Arrays.toString(numbers));
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,182 @@
|
||||
package com.ossez.collections.bitset;
|
||||
|
||||
import org.junit.Test;
|
||||
import org.openjdk.jol.info.ClassLayout;
|
||||
import org.openjdk.jol.info.GraphLayout;
|
||||
import org.slf4j.Logger;
|
||||
import org.slf4j.LoggerFactory;
|
||||
|
||||
import java.util.BitSet;
|
||||
|
||||
import static org.assertj.core.api.Assertions.assertThat;
|
||||
|
||||
public class BitSetUnitTest {
|
||||
|
||||
private static final Logger LOG = LoggerFactory.getLogger(BitSetUnitTest.class);
|
||||
|
||||
@Test
|
||||
public void givenBoolArray_whenMemoryLayout_thenConsumeMoreThanOneBit() {
|
||||
boolean[] bits = new boolean[1024 * 1024];
|
||||
|
||||
LOG.debug(ClassLayout.parseInstance(bits).toPrintable());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenMemoryLayout_thenConsumeOneBitPerFlag() {
|
||||
BitSet bitSet = new BitSet(1024 * 1024);
|
||||
|
||||
LOG.debug(GraphLayout.parseInstance(bitSet).toPrintable());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenSetting_thenShouldBeTrue() {
|
||||
BitSet bitSet = new BitSet();
|
||||
|
||||
bitSet.set(10);
|
||||
assertThat(bitSet.get(10)).isTrue();
|
||||
|
||||
bitSet.set(20, 30);
|
||||
for (int i = 20; i <= 29; i++) {
|
||||
assertThat(bitSet.get(i)).isTrue();
|
||||
}
|
||||
assertThat(bitSet.get(30)).isFalse();
|
||||
|
||||
bitSet.set(10, false);
|
||||
assertThat(bitSet.get(10)).isFalse();
|
||||
|
||||
bitSet.set(20, 30, false);
|
||||
for (int i = 20; i <= 30; i++) {
|
||||
assertThat(bitSet.get(i)).isFalse();
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenClearing_thenShouldBeFalse() {
|
||||
BitSet bitSet = new BitSet();
|
||||
bitSet.set(42);
|
||||
assertThat(bitSet.get(42)).isTrue();
|
||||
|
||||
bitSet.clear(42);
|
||||
assertThat(bitSet.get(42)).isFalse();
|
||||
|
||||
bitSet.set(10, 20);
|
||||
for (int i = 10; i < 20; i++) {
|
||||
assertThat(bitSet.get(i)).isTrue();
|
||||
}
|
||||
|
||||
bitSet.clear(10, 20);
|
||||
for (int i = 10; i < 20; i++) {
|
||||
assertThat(bitSet.get(i)).isFalse();
|
||||
}
|
||||
|
||||
bitSet.set(10, 20);
|
||||
bitSet.clear();
|
||||
for (int i = 0; i < 100; i++) {
|
||||
assertThat(bitSet.get(i)).isFalse();
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenGettingElements_thenShouldReturnRequestedBits() {
|
||||
BitSet bitSet = new BitSet();
|
||||
bitSet.set(42);
|
||||
|
||||
assertThat(bitSet.get(42)).isTrue();
|
||||
assertThat(bitSet.get(43)).isFalse();
|
||||
|
||||
bitSet.set(10, 20);
|
||||
BitSet newBitSet = bitSet.get(10, 20);
|
||||
for (int i = 0; i < 10; i++) {
|
||||
assertThat(newBitSet.get(i)).isTrue();
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenFlip_thenTogglesTrueToFalseAndViceVersa() {
|
||||
BitSet bitSet = new BitSet();
|
||||
bitSet.set(42);
|
||||
bitSet.flip(42);
|
||||
assertThat(bitSet.get(42)).isFalse();
|
||||
|
||||
bitSet.flip(12);
|
||||
assertThat(bitSet.get(12)).isTrue();
|
||||
|
||||
bitSet.flip(30, 40);
|
||||
for (int i = 30; i < 40; i++) {
|
||||
assertThat(bitSet.get(i)).isTrue();
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenGettingTheSize_thenReturnsTheSize() {
|
||||
BitSet defaultBitSet = new BitSet();
|
||||
assertThat(defaultBitSet.size()).isEqualTo(64);
|
||||
|
||||
BitSet bitSet = new BitSet(1024);
|
||||
assertThat(bitSet.size()).isEqualTo(1024);
|
||||
|
||||
assertThat(bitSet.cardinality()).isEqualTo(0);
|
||||
bitSet.set(10, 30);
|
||||
assertThat(bitSet.cardinality()).isEqualTo(30 - 10);
|
||||
|
||||
assertThat(bitSet.length()).isEqualTo(30);
|
||||
bitSet.set(100);
|
||||
assertThat(bitSet.length()).isEqualTo(101);
|
||||
|
||||
assertThat(bitSet.isEmpty()).isFalse();
|
||||
bitSet.clear();
|
||||
assertThat(bitSet.isEmpty()).isTrue();
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenSetOperations_thenShouldReturnAnotherBitSet() {
|
||||
BitSet first = new BitSet();
|
||||
first.set(5, 10);
|
||||
|
||||
BitSet second = new BitSet();
|
||||
second.set(7, 15);
|
||||
|
||||
assertThat(first.intersects(second)).isTrue();
|
||||
|
||||
first.and(second);
|
||||
assertThat(first.get(7)).isTrue();
|
||||
assertThat(first.get(8)).isTrue();
|
||||
assertThat(first.get(9)).isTrue();
|
||||
assertThat(first.get(10)).isFalse();
|
||||
|
||||
first.clear();
|
||||
first.set(5, 10);
|
||||
|
||||
first.xor(second);
|
||||
for (int i = 5; i < 7; i++) {
|
||||
assertThat(first.get(i)).isTrue();
|
||||
}
|
||||
for (int i = 10; i < 15; i++) {
|
||||
assertThat(first.get(i)).isTrue();
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenStream_thenStreamsAllSetBits() {
|
||||
BitSet bitSet = new BitSet();
|
||||
bitSet.set(15, 25);
|
||||
|
||||
bitSet.stream().forEach(bit -> LOG.debug(String.valueOf(bit)));
|
||||
assertThat(bitSet.stream().count()).isEqualTo(10);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenBitSet_whenNextOrPrev_thenReturnsTheNextOrPrevClearOrSetBit() {
|
||||
BitSet bitSet = new BitSet();
|
||||
bitSet.set(15, 25);
|
||||
|
||||
assertThat(bitSet.nextSetBit(13)).isEqualTo(15);
|
||||
assertThat(bitSet.nextSetBit(25)).isEqualTo(-1);
|
||||
|
||||
assertThat(bitSet.nextClearBit(23)).isEqualTo(25);
|
||||
|
||||
assertThat(bitSet.previousClearBit(24)).isEqualTo(14);
|
||||
assertThat(bitSet.previousSetBit(29)).isEqualTo(24);
|
||||
assertThat(bitSet.previousSetBit(14)).isEqualTo(-1);
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,40 @@
|
||||
package com.ossez.collections.clearvsremoveall;
|
||||
|
||||
import org.junit.jupiter.api.Test;
|
||||
|
||||
import java.util.ArrayList;
|
||||
import java.util.Arrays;
|
||||
import java.util.Collection;
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
import static org.junit.Assert.assertTrue;
|
||||
|
||||
/**
|
||||
* Unit tests demonstrating differences between ArrayList#clear() and ArrayList#removeAll()
|
||||
*/
|
||||
class ClearVsRemoveAllUnitTest {
|
||||
|
||||
/*
|
||||
* Tests
|
||||
*/
|
||||
@Test
|
||||
void givenArrayListWithElements_whenClear_thenListBecomesEmpty() {
|
||||
Collection<Integer> collection = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5));
|
||||
|
||||
collection.clear();
|
||||
|
||||
assertTrue(collection.isEmpty());
|
||||
}
|
||||
|
||||
@Test
|
||||
void givenTwoArrayListsWithCommonElements_whenRemoveAll_thenFirstListMissElementsFromSecondList() {
|
||||
Collection<Integer> firstCollection = new ArrayList<>(Arrays.asList(1, 2, 3, 4, 5));
|
||||
Collection<Integer> secondCollection = new ArrayList<>(Arrays.asList(3, 4, 5, 6, 7));
|
||||
|
||||
firstCollection.removeAll(secondCollection);
|
||||
|
||||
assertEquals(Arrays.asList(1, 2), firstCollection);
|
||||
assertEquals(Arrays.asList(3, 4, 5, 6, 7), secondCollection);
|
||||
}
|
||||
|
||||
}
|
||||
@ -0,0 +1,98 @@
|
||||
package com.ossez.collections.hashmapvshashtable;
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
|
||||
import java.util.Collections;
|
||||
import java.util.ConcurrentModificationException;
|
||||
import java.util.Enumeration;
|
||||
import java.util.HashMap;
|
||||
import java.util.Hashtable;
|
||||
import java.util.Iterator;
|
||||
import java.util.List;
|
||||
import java.util.Map;
|
||||
import java.util.Map.Entry;
|
||||
import java.util.Set;
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
import com.google.common.collect.Lists;
|
||||
|
||||
public class HashmapVsHashtableDifferenceUnitTest {
|
||||
|
||||
// null values
|
||||
@Test(expected = NullPointerException.class)
|
||||
public void givenHashtable_whenAddNullKey_thenNullPointerExceptionThrown() {
|
||||
Hashtable<String, String> table = new Hashtable<String, String>();
|
||||
table.put(null, "value");
|
||||
}
|
||||
|
||||
@Test(expected = NullPointerException.class)
|
||||
public void givenHashtable_whenAddNullValue_thenNullPointerExceptionThrown() {
|
||||
Hashtable<String, String> table = new Hashtable<String, String>();
|
||||
table.put("key", null);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenHashmap_whenAddNullKeyAndValue_thenObjectAdded() {
|
||||
HashMap<String, String> map = new HashMap<String, String>();
|
||||
map.put(null, "value");
|
||||
map.put("key1", null);
|
||||
map.put("key2", null);
|
||||
|
||||
assertEquals(3, map.size());
|
||||
}
|
||||
|
||||
// fail-fast iterator
|
||||
@Test(expected = ConcurrentModificationException.class)
|
||||
public void givenHashmap_whenModifyUnderlyingCollection_thenConcurrentModificationExceptionThrown() {
|
||||
HashMap<String, String> map = new HashMap<String, String>();
|
||||
map.put("key1", "value1");
|
||||
map.put("key2", "value2");
|
||||
map.put("key3", "value3");
|
||||
|
||||
Iterator<String> iterator = map.keySet().iterator();
|
||||
while(iterator.hasNext()){
|
||||
iterator.next();
|
||||
map.put("key4", "value4");
|
||||
}
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenHashtable_whenModifyUnderlyingCollection_thenItHasNoEffectOnIteratedCollection() {
|
||||
Hashtable<String, String> table = new Hashtable<String, String>();
|
||||
table.put("key1", "value1");
|
||||
table.put("key2", "value2");
|
||||
|
||||
List<String> keysSelected = Lists.newArrayList();
|
||||
Enumeration<String> keys = table.keys();
|
||||
while (keys.hasMoreElements()) {
|
||||
String key = keys.nextElement();
|
||||
keysSelected.add(key);
|
||||
|
||||
if (key.equals("key1")) {
|
||||
table.put("key3", "value3");
|
||||
}
|
||||
}
|
||||
|
||||
assertEquals(2, keysSelected.size());
|
||||
}
|
||||
|
||||
// synchronized map
|
||||
@Test
|
||||
public void givenHashmap_thenCreateSynchronizedMap() {
|
||||
HashMap<String, String> map = new HashMap<String, String>();
|
||||
map.put("key1", "value1");
|
||||
map.put("key2", "value2");
|
||||
map.put("key3", "value3");
|
||||
|
||||
Set<Entry<String, String>> set = map.entrySet();
|
||||
synchronized (map) {
|
||||
Iterator<Entry<String, String>> it = set.iterator();
|
||||
while(it.hasNext()) {
|
||||
Map.Entry<String, String> elem = (Map.Entry<String, String>)it.next();
|
||||
}
|
||||
}
|
||||
|
||||
Map<String, String> syncMap = Collections.synchronizedMap(map);
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,33 @@
|
||||
package com.ossez.collections.hashset;
|
||||
|
||||
import static org.junit.jupiter.api.Assertions.*;
|
||||
|
||||
import java.util.ArrayList;
|
||||
import java.util.Collection;
|
||||
import java.util.HashSet;
|
||||
import java.util.Set;
|
||||
|
||||
import org.junit.jupiter.api.Test;
|
||||
|
||||
class HashSetUnitTest {
|
||||
|
||||
@Test
|
||||
void whenRemoveAllFromHashset_thenRemovesAllElementsFromHashsetThatArePresentInCollection() {
|
||||
Set<Integer> set = new HashSet<>();
|
||||
Collection<Integer> collection = new ArrayList<>();
|
||||
set.add(1);
|
||||
set.add(2);
|
||||
set.add(3);
|
||||
set.add(4);
|
||||
collection.add(1);
|
||||
collection.add(3);
|
||||
|
||||
set.removeAll(collection);
|
||||
|
||||
assertEquals(2, set.size());
|
||||
Integer[] actualElements = new Integer[set.size()];
|
||||
Integer[] expectedElements = new Integer[] { 2, 4 };
|
||||
assertArrayEquals(expectedElements, set.toArray(actualElements));
|
||||
}
|
||||
|
||||
}
|
||||
@ -0,0 +1,40 @@
|
||||
package com.ossez.collections.iterators;
|
||||
|
||||
import static com.ossez.collections.collections.iterators.Iterators.failFast1;
|
||||
import static com.ossez.collections.collections.iterators.Iterators.failFast2;
|
||||
import static com.ossez.collections.collections.iterators.Iterators.failSafe1;
|
||||
import static org.assertj.core.api.Assertions.assertThat;
|
||||
import static org.assertj.core.api.Assertions.assertThatThrownBy;
|
||||
|
||||
import java.util.ConcurrentModificationException;
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
/**
|
||||
* Source code https://github.com/eugenp/tutorials
|
||||
*
|
||||
* @author Santosh Thakur
|
||||
*/
|
||||
|
||||
public class IteratorsUnitTest {
|
||||
|
||||
@Test
|
||||
public void whenFailFast_ThenThrowsException() {
|
||||
assertThatThrownBy(() -> {
|
||||
failFast1();
|
||||
}).isInstanceOf(ConcurrentModificationException.class);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenFailFast_ThenThrowsExceptionInSecondIteration() {
|
||||
assertThatThrownBy(() -> {
|
||||
failFast2();
|
||||
}).isInstanceOf(ConcurrentModificationException.class);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenFailSafe_ThenDoesNotThrowException() {
|
||||
assertThat(failSafe1()).isGreaterThanOrEqualTo(0);
|
||||
}
|
||||
|
||||
}
|
||||
@ -0,0 +1,146 @@
|
||||
package com.ossez.collections.mapfirstpair;
|
||||
|
||||
import static org.junit.Assert.assertEquals;
|
||||
import static org.junit.Assert.assertNotEquals;
|
||||
|
||||
import java.util.AbstractMap;
|
||||
import java.util.HashMap;
|
||||
import java.util.Iterator;
|
||||
import java.util.LinkedHashMap;
|
||||
import java.util.Map;
|
||||
import java.util.Set;
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
public class MapFirstPairUnitTest {
|
||||
|
||||
private Map.Entry<Integer, String> getFirstPairUsingIterator(Map<Integer, String> map) {
|
||||
if (map == null || map.size() == 0) {
|
||||
return null;
|
||||
}
|
||||
|
||||
Iterator<Map.Entry<Integer, String>> iterator = map.entrySet()
|
||||
.iterator();
|
||||
|
||||
if (iterator.hasNext()) {
|
||||
return iterator.next();
|
||||
}
|
||||
|
||||
return null;
|
||||
}
|
||||
|
||||
private Map.Entry<Integer, String> getFirstPairUsingStream(Map<Integer, String> map) {
|
||||
if (map == null || map.size() == 0) {
|
||||
return null;
|
||||
}
|
||||
|
||||
Set<Map.Entry<Integer, String>> entrySet = map.entrySet();
|
||||
|
||||
return entrySet.stream()
|
||||
.findFirst()
|
||||
.get();
|
||||
}
|
||||
|
||||
private Map<Integer, String> populateMapValues(Map<Integer, String> map) {
|
||||
if (map != null) {
|
||||
map.put(5, "A");
|
||||
map.put(1, "B");
|
||||
map.put(2, "C");
|
||||
}
|
||||
return map;
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingIteratorForHashMap_thenFirstPairWhichWasNotInsertedFirst() {
|
||||
Map<Integer, String> hashMap = new HashMap<>();
|
||||
hashMap = populateMapValues(hashMap);
|
||||
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingIterator(hashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(1, "B");
|
||||
Map.Entry<Integer, String> pairInsertedFirst = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
assertNotEquals(pairInsertedFirst, actualValue);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingStreamForHashMap_thenFirstPairWhichWasNotInsertedFirst() {
|
||||
Map<Integer, String> hashMap = new HashMap<>();
|
||||
hashMap = populateMapValues(hashMap);
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingStream(hashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(1, "B");
|
||||
Map.Entry<Integer, String> pairInsertedFirst = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
assertNotEquals(pairInsertedFirst, actualValue);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingIteratorForLinkedHashMap_thenFirstPairWhichWasInsertedFirst() {
|
||||
Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
|
||||
linkedHashMap = populateMapValues(linkedHashMap);
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingIterator(linkedHashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenUsingStreamForLinkedHashMap_thenFirstPairWhichWasInsertedFirst() {
|
||||
Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
|
||||
linkedHashMap = populateMapValues(linkedHashMap);
|
||||
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingStream(linkedHashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenAddedAnElementInHashMap_thenFirstPairChangedUsingIterator() {
|
||||
Map<Integer, String> hashMap = new HashMap<>();
|
||||
hashMap = populateMapValues(hashMap);
|
||||
|
||||
hashMap.put(0, "D");
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingIterator(hashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(0, "D");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenAddedAnElementInHashMap_thenFirstPairChangedUsingStream() {
|
||||
Map<Integer, String> hashMap = new HashMap<>();
|
||||
hashMap = populateMapValues(hashMap);
|
||||
|
||||
hashMap.put(0, "D");
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingStream(hashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(0, "D");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenAddedAnElementInLinkedHashMap_thenFirstPairRemainUnchangedUsingIterator() {
|
||||
Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
|
||||
linkedHashMap = populateMapValues(linkedHashMap);
|
||||
|
||||
linkedHashMap.put(0, "D");
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingIterator(linkedHashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenAddedAnElementInLinkedHashMap_thenFirstPairRemainUnchangedUsingStream() {
|
||||
Map<Integer, String> linkedHashMap = new LinkedHashMap<>();
|
||||
linkedHashMap = populateMapValues(linkedHashMap);
|
||||
|
||||
linkedHashMap.put(0, "D");
|
||||
Map.Entry<Integer, String> actualValue = getFirstPairUsingStream(linkedHashMap);
|
||||
Map.Entry<Integer, String> expectedValue = new AbstractMap.SimpleEntry<Integer, String>(5, "A");
|
||||
|
||||
assertEquals(expectedValue, actualValue);
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,183 @@
|
||||
package com.ossez.collections.stack;
|
||||
|
||||
import org.junit.Test;
|
||||
|
||||
import java.util.Arrays;
|
||||
import java.util.List;
|
||||
import java.util.ListIterator;
|
||||
import java.util.Stack;
|
||||
import java.util.stream.Collectors;
|
||||
|
||||
import static org.hamcrest.CoreMatchers.equalTo;
|
||||
import static org.junit.Assert.assertEquals;
|
||||
import static org.junit.Assert.assertThat;
|
||||
import static org.junit.Assert.assertTrue;
|
||||
public class StackUnitTest {
|
||||
|
||||
@Test
|
||||
public void whenStackIsCreated_thenItHasSizeZero() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
|
||||
assertEquals(0, intStack.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenElementIsPushed_thenStackSizeIsIncreased() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(1);
|
||||
|
||||
assertEquals(1, intStack.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenMultipleElementsArePushed_thenStackSizeIsIncreased() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
List<Integer> intList = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
|
||||
|
||||
boolean result = intStack.addAll(intList);
|
||||
|
||||
assertTrue(result);
|
||||
assertEquals(7, intList.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenElementIsPoppedFromStack_thenElementIsRemovedAndSizeChanges() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
|
||||
Integer element = intStack.pop();
|
||||
|
||||
assertEquals(Integer.valueOf(5), element);
|
||||
assertTrue(intStack.isEmpty());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenElementIsPeeked_thenElementIsNotRemovedAndSizeDoesNotChange() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
|
||||
Integer element = intStack.peek();
|
||||
|
||||
assertEquals(Integer.valueOf(5), element);
|
||||
assertEquals(1, intStack.search(5));
|
||||
assertEquals(1, intStack.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenElementIsOnStack_thenSearchReturnsItsDistanceFromTheTop() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
intStack.push(8);
|
||||
|
||||
assertEquals(2, intStack.search(5));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenElementIsOnStack_thenIndexOfReturnsItsIndex() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
|
||||
int indexOf = intStack.indexOf(5);
|
||||
|
||||
assertEquals(0, indexOf);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenMultipleElementsAreOnStack_thenIndexOfReturnsLastElementIndex() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
intStack.push(5);
|
||||
intStack.push(5);
|
||||
|
||||
int lastIndexOf = intStack.lastIndexOf(5);
|
||||
|
||||
assertEquals(2, lastIndexOf);
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenRemoveElementIsInvoked_thenElementIsRemoved() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
intStack.push(5);
|
||||
|
||||
intStack.removeElement(5);
|
||||
|
||||
assertEquals(1, intStack.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenRemoveElementAtIsInvoked_thenElementIsRemoved() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
intStack.push(7);
|
||||
|
||||
intStack.removeElementAt(1);
|
||||
|
||||
assertEquals(-1, intStack.search(7));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenRemoveAllElementsIsInvoked_thenAllElementsAreRemoved() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
intStack.push(5);
|
||||
intStack.push(7);
|
||||
|
||||
intStack.removeAllElements();
|
||||
|
||||
assertTrue(intStack.isEmpty());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void givenElementsOnStack_whenRemoveAllIsInvoked_thenAllElementsFromCollectionAreRemoved() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
List<Integer> intList = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
|
||||
intStack.addAll(intList);
|
||||
intStack.add(500);
|
||||
|
||||
intStack.removeAll(intList);
|
||||
|
||||
assertEquals(1, intStack.size());
|
||||
assertEquals(1, intStack.search(500));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenRemoveIfIsInvoked_thenAllElementsSatysfyingConditionAreRemoved() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
List<Integer> intList = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
|
||||
intStack.addAll(intList);
|
||||
|
||||
intStack.removeIf(element -> element < 6);
|
||||
|
||||
assertEquals(2, intStack.size());
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenAnotherStackCreatedWhileTraversingStack_thenStacksAreEqual() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
List<Integer> intList = Arrays.asList(1, 2, 3, 4, 5, 6, 7);
|
||||
intStack.addAll(intList);
|
||||
|
||||
ListIterator<Integer> it = intStack.listIterator();
|
||||
|
||||
Stack<Integer> result = new Stack<>();
|
||||
while(it.hasNext()) {
|
||||
result.push(it.next());
|
||||
}
|
||||
|
||||
assertThat(result, equalTo(intStack));
|
||||
}
|
||||
|
||||
@Test
|
||||
public void whenStackIsFiltered_allElementsNotSatisfyingFilterConditionAreDiscarded() {
|
||||
Stack<Integer> intStack = new Stack<>();
|
||||
List<Integer> inputIntList = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 9, 10);
|
||||
intStack.addAll(inputIntList);
|
||||
|
||||
List<Integer> filtered = intStack
|
||||
.stream()
|
||||
.filter(element -> element <= 3)
|
||||
.collect(Collectors.toList());
|
||||
|
||||
assertEquals(3, filtered.size());
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,13 @@
|
||||
<?xml version="1.0" encoding="UTF-8"?>
|
||||
<configuration>
|
||||
<appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
|
||||
<encoder>
|
||||
<pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n
|
||||
</pattern>
|
||||
</encoder>
|
||||
</appender>
|
||||
|
||||
<root level="INFO">
|
||||
<appender-ref ref="STDOUT" />
|
||||
</root>
|
||||
</configuration>
|
||||
Loading…
x
Reference in New Issue
Block a user