package devmanuals.com;

import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentHashMap;
import java.util.Set;

class CMPutIfAbsent1 implements Runnable {
	String name;

	ConcurrentMap<Integer, String> cm;

	public CMPutIfAbsent1(ConcurrentMap<Integer, String> cm, String name) {
		this.name = name;
		this.cm = cm;
	}

	public void run() {
		try {
			cm.put(1, "A");
			cm.put(2, "B");
			cm.put(3, "C");
			cm.put(4, "D");
			cm.put(5, "E");
			System.out.println(name + " maps the element : " + cm);
			System.out.println(name + " represents the set of keys: "
					+ cm.keySet());
			Thread.sleep(500);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

class CMPutIfAbsent2 implements Runnable {
	String name;

	ConcurrentMap<Integer, String> cm;

	public CMPutIfAbsent2(ConcurrentMap<Integer, String> cm, String name) {
		this.name = name;
		this.cm = cm;
	}

	public void run() {
		try {
			boolean j = cm.remove(3, "C");
			System.out.println(name + " removes the element : " + j);
			Thread.sleep(500);

		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

class CMPutIfAbsent3 implements Runnable {
	String name;

	ConcurrentMap<Integer, String> cm;

	public CMPutIfAbsent3(ConcurrentMap<Integer, String> cm, String name) {
		this.name = name;
		this.cm = cm;
	}

	public void run() {
		try {
			Set<Integer> s = cm.keySet();
			System.out
					.println(name + " represents " + "the set of keys : " + s);
			// here the implementation of this method
			// will return the previous value associated with key '4'
			String st = cm.putIfAbsent(4, "D");
			System.out.println(name+" returns the previous value : " + st);
			// here the implementation of this method
			// will return the 'null' value associated with key '4'
			st = cm.putIfAbsent(3, "C");
			System.out.println(name+" returns : " + st);
			Thread.sleep(500);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

public class CMPutIfAbsent {
	public static void main(String[] args) {
		ConcurrentMap<Integer, String> cm = new ConcurrentHashMap<Integer, String>();
		Runnable a = new CMPutIfAbsent1(cm, "A");
		Runnable b = new CMPutIfAbsent2(cm, "B");
		Runnable c = new CMPutIfAbsent3(cm, "C");
		new Thread(a).start();
		try {
			Thread.sleep(300);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		new Thread(b).start();
		try {
			Thread.sleep(300);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		new Thread(c).start();
		try {
			Thread.sleep(300);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}