11.11 Queue

import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.PriorityQueue;
import java.util.Queue;
import java.util.Random;
import java.util.Set;

public class PriorityQueueDemo{ 
	
	public static void printQ(Queue queue){
		while(queue.peek() != null){
			System.out.print(queue.remove() + " ");
		}
		System.out.println();
	}
	
	public static void main(String[] args){
		PriorityQueue<Integer> priorityQueue = new PriorityQueue<Integer>();
		Random random = new Random(47);
		for(int i = 0; i < 10; ++i){
			priorityQueue.offer(random.nextInt(i+10));
		}
		printQ(priorityQueue);
		List<Integer> ints = Arrays.asList(25,22,20,18,14,9,3,1,1,2,3,9,14,18,21,23,25);
		priorityQueue = new PriorityQueue<Integer>(ints);
		printQ(priorityQueue);
		priorityQueue = new PriorityQueue<Integer>(ints.size(), Collections.reverseOrder());
		priorityQueue.addAll(ints);
		printQ(priorityQueue);
		
		String fact = "EDUCATION SHOULD ESCHEW OBFUSCATION";
		List<String> strings = Arrays.asList(fact.split(""));
		PriorityQueue<String> stringPQ = new PriorityQueue<String>(strings);
		printQ(stringPQ);
		stringPQ = new PriorityQueue<String>(strings.size(), Collections.reverseOrder());
		stringPQ.addAll(strings);
		printQ(stringPQ);
		
		Set<Character> charset = new HashSet<Character>();
		for(char c: fact.toCharArray()){
			charset.add(c);
		}
		PriorityQueue<Character> cQueue = new PriorityQueue<Character>(charset);
		printQ(cQueue);
	}
}

0 1 1 1 1 1 3 5 8 14 
1 1 2 3 3 9 9 14 14 18 18 20 21 22 23 25 25 
25 25 23 22 21 20 18 18 14 14 9 9 3 3 2 1 1 
       A A B C C C D D E E E F H H I I L N N O O O O S S S T T U U U W 
W U U U T T S S S O O O O N N L I I H H F E E E D D C C C B A A        
  A B C D E F H I L N O S T U W 

11.13 Foreach 및 교체기

import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;

public class ForeachCollections{ 
	
	public static void main(String[] args){
		Collection<String> cs = new LinkedList<String>();
		Collections.addAll(cs, "Take the long way home".split(" "));
		for(String s: cs){
			System.out.print(" " + s + " ");
		}
	}	
}

import java.util.Iterator;

public class IterableClass implements Iterable<String>{ 
	
	protected String[] words = "And that is how we know the Earch to be banana-shaped.".split(" ");
	
	public static void main(String[] args){
		for(String s: new IterableClass()){
			System.out.print(s + " ");
		}
	}

	@Override
	public Iterator<String> iterator() {
		// TODO Auto-generated method stub
		return new Iterator<String>(){
			private int index = 0;

			@Override
			public boolean hasNext() {
				// TODO Auto-generated method stub
				return index < words.length;
			}

			@Override
			public String next() {
				// TODO Auto-generated method stub
				return words[index++];
			}

			@Override
			public void remove() {
				// TODO Auto-generated method stub
				throw new UnsupportedOperationException();
			}
		};
	}	
}

import java.util.Arrays;

public class ArrayIsNotIterable {  
	static <T> void test(Iterable<T> ib){
		for(T t : ib){
			System.out.print(t + " ");
		}
		System.out.println();
	}
	
	public static void main(String[] args){
		test(Arrays.asList(1,2,3));
		String[]strings = {"A","B","C"};
		//array , iterable
		//test(strings);
		test(Arrays.asList(strings));
	}
}

11.3.1 어댑터 방법 관용

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Random;

public class MultiIterableClass extends IterableClass {  
	
	public Iterable<String> resversed(){
		return new Iterable<String>(){
			@Override
			public Iterator<String> iterator() {
				// TODO Auto-generated method stub
				return new Iterator<String>(){

					int current = words.length-1;
					@Override
					public boolean hasNext() {
						// TODO Auto-generated method stub
						return current > -1;
					}

					@Override
					public String next() {
						// TODO Auto-generated method stub
						return words[current--];
					}

					@Override
					public void remove() {
						// TODO Auto-generated method stub
						throw new UnsupportedOperationException();
					}	
				};
			}
		};
	}
	
	public Iterable<String> randomized(){
		return new Iterable<String>(){

			@Override
			public Iterator<String> iterator() {
				// TODO Auto-generated method stub
				List<String> shuffled = new ArrayList<String>(Arrays.asList(words));
				Collections.shuffle(shuffled, new Random(47));
				return shuffled.iterator();
			}
		};
	}
	
	public static void main(String[] args){
		MultiIterableClass mic = new MultiIterableClass();
		for(String s:mic.resversed()){
			System.out.print(s + " ");
		}
		System.out.println();
		for(String s:mic.randomized()){
			System.out.print(s + " ");
		}
		System.out.println();
		for(String s:mic){
			System.out.print(s + " ");
		}
	}
}

banana-shaped. be to Earch the know we how is that And 
is banana-shaped. Earch that how the be And we know to 
And that is how we know the Earch to be banana-shaped. 

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Random;

public class ModifyingArrayAsList {  
	
	public static void main(String[] args){
		Random random = new Random(47);
		Integer[] ia = {1,2,3,4,5,6,7,8,9,10};
		List<Integer> list1 = new ArrayList<Integer>(Arrays.asList(ia));
		System.out.println("Before shuffling: " + list1);
		Collections.shuffle(list1, random);
		System.out.println("After shuffling: " + list1);
		
		System.out.println("array: " + Arrays.toString(ia));
		
		List<Integer> list2 = Arrays.asList(ia);
		System.out.println("Before shuffling: " + list2);
		Collections.shuffle(list2, random);
		System.out.println("After shuffling: " + list2);
		System.out.println("array: " + Arrays.toString(ia));
	}
}