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OneCodeOneTimeOneCodeOneTime
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Chapter 17 Collections btp170618
* 170537-Generic * 0528-Generic * Chapter-15-Generic-btp0530 * Chapter-16-Arrays-btp170603 * Chapter-17-Collections-btp170618
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‎src/btp/oneP/CollectionDataTest.java‎

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package btp.oneP;
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import java.util.ArrayList;
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import java.util.LinkedHashSet;
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import java.util.Set;
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public class CollectionDataTest {
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public static void main(String[] args) {
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Set<String> set = new LinkedHashSet<String>(new CollectionData<String>(new Government(),7));
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set.addAll(CollectionData.list(new Government(), 7));
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System.out.println(set);
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}
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}
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class CollectionData<T> extends ArrayList<T> {
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public CollectionData(GeneratorN<T> gen,int quantity){
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for(int i=0;i<quantity;i++){
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this.add(gen.next());
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}
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}
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public static <T> CollectionData<T> list(GeneratorN<T> gen,int quantity){
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return new CollectionData<T>(gen,quantity);
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}
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}
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interface GeneratorN<T>{
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T next();
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}
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class Government implements GeneratorN<String>{
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String[] foundation = "you are a hero not a coward".split(" ");
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private int index;
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@Override
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public String next() {
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// TODO Auto-generated method stub
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return foundation[index++];
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}
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}
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‎src/btp/oneP/FillingLists.java‎

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package btp.oneP;
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import java.util.ArrayList;
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import java.util.Collections;
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import java.util.List;
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public class FillingLists {
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@SuppressWarnings("unchecked")
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public static void main(String[] args) {
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List<StringAddress> list = (List) Collections.nCopies(4, new StringAddress("hehe"));
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System.out.println(list);
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list = new ArrayList<StringAddress>(list);
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System.out.println(list);
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Collections.fill(list, new StringAddress("xixi"));
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System.out.println(list);
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}
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}
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class StringAddress{
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private String s;
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public StringAddress(String s){
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this.s = s;
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}
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public String toString(){
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return super.toString()+" "+s;
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}
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}

‎src/btp/oneP/MapDataTest.java‎

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package btp.oneP;
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import java.util.Iterator;
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import java.util.LinkedHashMap;
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public class MapDataTest {
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public static void main(String[] args) {
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System.out.println(MapData.map(new Letters(), 11));
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System.out.println(MapData.map(new Letters(), "Pop"));
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}
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}
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class PairN<K,V>{
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public final K key;
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public final V value;
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public PairN(K k,V v){
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this.key = k;
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this.value = v;
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}
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}
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class MapData<K,V> extends LinkedHashMap<K,V>{
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public MapData(GeneratorN<PairN<K,V>> gen,int quantity){
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for(int i=0;i<quantity;i++){
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PairN<K,V> p = gen.next();
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this.put(p.key, p.value);
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}
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}
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public MapData(GeneratorN<K> genK,GeneratorN<V> genV,int quantity){
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for(int i=0;i<quantity;i++){
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this.put(genK.next(), genV.next());
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}
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}
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public MapData(GeneratorN<K> genK,V value,int quantity){
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for(int i=0;i<quantity;i++){
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this.put(genK.next(), value);
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}
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}
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public MapData(Iterable<K> genK,GeneratorN<V> genV){
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for(K key:genK){
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this.put(key,genV.next());
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}
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}
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public MapData(Iterable<K> genK, V value){
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for(K key:genK){
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this.put(key, value);
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}
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}
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public static <K,V> MapData<K,V> map(GeneratorN<PairN<K,V>> gen,int quantity){
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return new MapData<K,V>(gen,quantity);
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}
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public static <K,V> MapData<K,V> map(GeneratorN<K> genK,GeneratorN<V> genV,int quantity){
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return new MapData<K,V>(genK,genV,quantity);
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}
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public static <K,V> MapData<K,V> map(GeneratorN<K> genK,V value,int quantity){
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return new MapData<K,V>(genK,value,quantity);
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}
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public static <K,V> MapData<K,V> map(Iterable<K> genK,GeneratorN<V> genV){
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return new MapData<K,V>(genK,genV);
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}
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public static <K,V> MapData<K,V> map(Iterable<K> genK,V value){
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return new MapData<K,V>(genK,value);
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}
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}
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class Letters implements GeneratorN<PairN<Integer,String>>,
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Iterable<Integer>{
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private int size = 9;
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private int number = 1;
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private char letter = 'A';
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@Override
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public PairN<Integer, String> next() {
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return new PairN<Integer,String>(number++,""+letter++);
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}
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@Override
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public Iterator<Integer> iterator() {
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// TODO Auto-generated method stub
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return new Iterator<Integer>(){
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@Override
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public boolean hasNext() {
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// TODO Auto-generated method stub
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return number < size;
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}
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@Override
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public Integer next() {
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// TODO Auto-generated method stub
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return number++;
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}
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};
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}
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}

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