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iluwatariluwatar
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added memento sample
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7 files changed

+185
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lines changed

‎memento/pom.xml‎

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<?xml version="1.0"?>
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<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" 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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<modelVersion>4.0.0</modelVersion>
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<parent>
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<groupId>com.iluwatar</groupId>
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<artifactId>java-design-patterns</artifactId>
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<version>1.0-SNAPSHOT</version>
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</parent>
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<groupId>com.iluwatar</groupId>
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<artifactId>memento</artifactId>
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<version>1.0-SNAPSHOT</version>
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<name>memento</name>
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<url>http://maven.apache.org</url>
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<dependencies>
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<dependency>
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<groupId>junit</groupId>
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<artifactId>junit</artifactId>
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<version>3.8.1</version>
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<scope>test</scope>
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</dependency>
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</dependencies>
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</project>

‎memento/src/main/java/com/iluwatar/App.java‎

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package com.iluwatar;
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import java.util.Stack;
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public class App
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{
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public static void main( String[] args )
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{
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Stack<StarMemento> states = new Stack<>();
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Star star = new Star(StarType.SUN, 10000000, 500000);
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System.out.println(star);
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states.add(star.getMemento());
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star.timePasses();
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System.out.println(star);
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states.add(star.getMemento());
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star.timePasses();
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System.out.println(star);
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states.add(star.getMemento());
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star.timePasses();
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System.out.println(star);
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states.add(star.getMemento());
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star.timePasses();
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System.out.println(star);
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while (states.size() > 0) {
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star.setMemento(states.pop());
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System.out.println(star);
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}
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}
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}

‎memento/src/main/java/com/iluwatar/Star.java‎

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package com.iluwatar;
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public class Star {
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private StarType type;
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private int ageYears;
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private int massTons;
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public Star(StarType startType, int startAge, int startMass) {
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this.type = startType;
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this.ageYears = startAge;
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this.massTons = startMass;
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}
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public void timePasses() {
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ageYears *= 2;
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massTons *= 8;
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switch (type) {
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case RED_GIANT:
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type = StarType.WHITE_DWARF;
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break;
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case SUN:
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type = StarType.RED_GIANT;
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break;
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case SUPERNOVA:
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type = StarType.DEAD;
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break;
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case WHITE_DWARF:
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type = StarType.SUPERNOVA;
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break;
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case DEAD:
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ageYears *= 2;
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massTons = 0;
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break;
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default:
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break;
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}
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}
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StarMemento getMemento() {
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StarMementoInternal state = new StarMementoInternal();
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state.setAgeYears(ageYears);
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state.setMassTons(massTons);
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state.setType(type);
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return state;
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}
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void setMemento(StarMemento memento) {
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StarMementoInternal state = (StarMementoInternal) memento;
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this.type = state.getType();
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this.ageYears = state.getAgeYears();
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this.massTons = state.getMassTons();
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}
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@Override
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public String toString() {
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return String.format("%s age: %d years mass: %d tons", type.toString(), ageYears, massTons);
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}
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}

‎memento/src/main/java/com/iluwatar/StarMemento.java‎

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package com.iluwatar;
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public interface StarMemento {
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}

‎memento/src/main/java/com/iluwatar/StarMementoInternal.java‎

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package com.iluwatar;
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public class StarMementoInternal implements StarMemento {
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private StarType type;
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private int ageYears;
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private int massTons;
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public StarType getType() {
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return type;
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}
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public void setType(StarType type) {
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this.type = type;
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}
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public int getAgeYears() {
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return ageYears;
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}
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public void setAgeYears(int ageYears) {
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this.ageYears = ageYears;
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}
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public int getMassTons() {
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return massTons;
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}
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public void setMassTons(int massTons) {
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this.massTons = massTons;
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}
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}

‎memento/src/main/java/com/iluwatar/StarType.java‎

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package com.iluwatar;
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public enum StarType {
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SUN,
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RED_GIANT,
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WHITE_DWARF,
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SUPERNOVA,
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DEAD;
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@Override
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public String toString() {
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String s = "";
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switch (this) {
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case RED_GIANT:
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s = "red giant";
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break;
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case SUN:
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s = "sun";
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break;
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case SUPERNOVA:
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s = "supernova";
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break;
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case WHITE_DWARF:
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s = "white dwarf";
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break;
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case DEAD:
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s = "dead star";
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break;
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default:
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break;
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}
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return s;
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}
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}

‎pom.xml‎

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<module>interpreter</module>
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<module>iterator</module>
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<module>mediator</module>
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<module>memento</module>
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</modules>
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<build>

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