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‎chap1/FilteringApples.java‎

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import java.util.*;
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import java.util.function.Predicate;
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public class FilteringApples{
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public static void main(String ... args){
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List<Apple> inventory = Arrays.asList(new Apple(80,"green"), new Apple(155, "green"), new Apple(120, "red"));
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// [Apple{color='green', weight=80}, Apple{color='green', weight=155}]
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List<Apple> greenApples = filterApples(inventory, FilteringApples::isGreenApple);
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System.out.println(greenApples);
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// [Apple{color='green', weight=155}]
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List<Apple> heavyApples = filterApples(inventory, FilteringApples::isHeavyApple);
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System.out.println(heavyApples);
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// [Apple{color='green', weight=80}, Apple{color='green', weight=155}]
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List<Apple> greenApples2 = filterApples(inventory, (Apple a) -> "green".equals(a.getColor()));
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System.out.println(greenApples2);
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// [Apple{color='green', weight=155}]
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List<Apple> heavyApples2 = filterApples(inventory, (Apple a) -> a.getWeight() > 150);
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System.out.println(heavyApples2);
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// []
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List<Apple> weirdApples = filterApples(inventory, (Apple a) -> a.getWeight() < 80 ||
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"brown".equals(a.getColor()));
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System.out.println(weirdApples);
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}
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public static List<Apple> filterGreenApples(List<Apple> inventory){
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List<Apple> result = new ArrayList<>();
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for (Apple apple: inventory){
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if ("green".equals(apple.getColor())) {
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result.add(apple);
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}
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}
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return result;
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}
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public static List<Apple> filterHeavyApples(List<Apple> inventory){
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List<Apple> result = new ArrayList<>();
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for (Apple apple: inventory){
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if (apple.getWeight() > 150) {
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result.add(apple);
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}
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}
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return result;
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}
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public static boolean isGreenApple(Apple apple) {
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return "green".equals(apple.getColor());
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}
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public static boolean isHeavyApple(Apple apple) {
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return apple.getWeight() > 150;
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}
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public static List<Apple> filterApples(List<Apple> inventory, Predicate<Apple> p){
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List<Apple> result = new ArrayList<>();
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for(Apple apple : inventory){
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if(p.test(apple)){
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result.add(apple);
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}
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}
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return result;
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}
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public static class Apple {
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private int weight = 0;
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private String color = "";
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public Apple(int weight, String color){
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this.weight = weight;
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this.color = color;
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}
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public Integer getWeight() {
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return weight;
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}
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public void setWeight(Integer weight) {
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this.weight = weight;
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}
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public String getColor() {
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return color;
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}
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public void setColor(String color) {
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this.color = color;
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}
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public String toString() {
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return "Apple{" +
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"color='" + color + '\'' +
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", weight=" + weight +
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'}';
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}
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}
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}

‎chap2/FilteringApples.java‎

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import java.util.*;
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public class FilteringApples{
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public static void main(String ... args){
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List<Apple> inventory = Arrays.asList(new Apple(80,"green"), new Apple(155, "green"), new Apple(120, "red"));
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// [Apple{color='green', weight=80}, Apple{color='green', weight=155}]
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List<Apple> greenApples = filterApplesByColor(inventory, "green");
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System.out.println(greenApples);
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// [Apple{color='red', weight=120}]
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List<Apple> redApples = filterApplesByColor(inventory, "red");
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System.out.println(redApples);
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// [Apple{color='green', weight=80}, Apple{color='green', weight=155}]
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List<Apple> greenApples2 = filter(inventory, new AppleColorPredicate());
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System.out.println(greenApples2);
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// [Apple{color='green', weight=155}]
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List<Apple> heavyApples = filter(inventory, new AppleWeightPredicate());
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System.out.println(heavyApples);
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// []
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List<Apple> redAndHeavyApples = filter(inventory, new AppleRedAndHeavyPredicate());
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System.out.println(redAndHeavyApples);
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// [Apple{color='red', weight=120}]
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List<Apple> redApples2 = filter(inventory, new ApplePredicate() {
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public boolean test(Apple a){
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return a.getColor().equals("red");
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}
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});
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System.out.println(redApples2);
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}
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public static List<Apple> filterGreenApples(List<Apple> inventory){
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List<Apple> result = new ArrayList<>();
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for(Apple apple: inventory){
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if("green".equals(apple.getColor())){
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result.add(apple);
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}
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}
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return result;
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}
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public static List<Apple> filterApplesByColor(List<Apple> inventory, String color){
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List<Apple> result = new ArrayList<>();
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for(Apple apple: inventory){
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if(apple.getColor().equals(color)){
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result.add(apple);
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}
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}
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return result;
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}
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public static List<Apple> filterApplesByWeight(List<Apple> inventory, int weight){
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List<Apple> result = new ArrayList<>();
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for(Apple apple: inventory){
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if(apple.getWeight() > weight){
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result.add(apple);
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}
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}
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return result;
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}
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public static List<Apple> filter(List<Apple> inventory, ApplePredicate p){
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List<Apple> result = new ArrayList<>();
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for(Apple apple : inventory){
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if(p.test(apple)){
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result.add(apple);
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}
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}
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return result;
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}
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public static class Apple {
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private int weight = 0;
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private String color = "";
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public Apple(int weight, String color){
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this.weight = weight;
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this.color = color;
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}
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public Integer getWeight() {
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return weight;
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}
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public void setWeight(Integer weight) {
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this.weight = weight;
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}
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public String getColor() {
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return color;
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}
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public void setColor(String color) {
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this.color = color;
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}
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public String toString() {
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return "Apple{" +
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"color='" + color + '\'' +
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", weight=" + weight +
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'}';
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}
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}
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interface ApplePredicate{
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public boolean test(Apple a);
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}
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static class AppleWeightPredicate implements ApplePredicate{
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public boolean test(Apple apple){
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return apple.getWeight() > 150;
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}
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}
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static class AppleColorPredicate implements ApplePredicate{
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public boolean test(Apple apple){
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return "green".equals(apple.getColor());
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}
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}
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static class AppleRedAndHeavyPredicate implements ApplePredicate{
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public boolean test(Apple apple){
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return "red".equals(apple.getColor())
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&& apple.getWeight() > 150;
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}
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}
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}

‎chap2/MeaningOfThis.java‎

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public class MeaningOfThis
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{
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public final int value = 4;
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public void doIt()
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{
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int value = 6;
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Runnable r = new Runnable(){
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public final int value = 5;
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public void run(){
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int value = 10;
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System.out.println(this.value);
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}
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};
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r.run();
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}
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public static void main(String...args)
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{
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MeaningOfThis m = new MeaningOfThis();
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m.doIt(); // ???
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}
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}

‎chap3/ExecuteAround.java‎

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import java.io.*;
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public class ExecuteAround {
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public static void main(String ...args) throws IOException{
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String oneLine = processFile((BufferedReader b) -> b.readLine());
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System.out.println(oneLine);
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String twoLines = processFile((BufferedReader b) -> b.readLine() + b.readLine());
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System.out.println(twoLines);
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}
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public static String processFile(BufferedReaderProcessor p) throws IOException {
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try(BufferedReader br = new BufferedReader(new FileReader("data.txt"))){
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return p.process(br);
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}
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}
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public interface BufferedReaderProcessor{
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public String process(BufferedReader b) throws IOException;
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}
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}

‎chap3/Lambdas.java‎

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import java.util.*;
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public class Lambdas {
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public static void main(String ...args){
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// Simple example
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Runnable r = () -> System.out.println("Hello!");
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r.run();
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// Filtering with lambdas
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List<Apple> inventory = Arrays.asList(new Apple(80,"green"), new Apple(155, "green"), new Apple(120, "red"));
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// [Apple{color='green', weight=80}, Apple{color='green', weight=155}]
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List<Apple> greenApples = filter(inventory, (Apple a) -> "green".equals(a.getColor()));
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System.out.println(greenApples);
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Comparator<Apple> c = (Apple a1, Apple a2) -> a1.getWeight().compareTo(a2.getWeight());
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// [Apple{color='green', weight=80}, Apple{color='red', weight=120}, Apple{color='green', weight=155}]
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inventory.sort(c);
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System.out.println(inventory);
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}
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public static List<Apple> filter(List<Apple> inventory, ApplePredicate p){
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List<Apple> result = new ArrayList<>();
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for(Apple apple : inventory){
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if(p.test(apple)){
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result.add(apple);
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}
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}
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return result;
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}
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public static class Apple {
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private int weight = 0;
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private String color = "";
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public Apple(int weight, String color){
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this.weight = weight;
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this.color = color;
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}
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public Integer getWeight() {
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return weight;
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}
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public void setWeight(Integer weight) {
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this.weight = weight;
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}
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public String getColor() {
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return color;
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}
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public void setColor(String color) {
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this.color = color;
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}
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public String toString() {
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return "Apple{" +
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"color='" + color + '\'' +
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", weight=" + weight +
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'}';
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}
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}
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interface ApplePredicate{
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public boolean test(Apple a);
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}
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}

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