ConcurrentSet.java

package br.com.etyllica.util.concurrency;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class ConcurrentSet<T> {

	private Set<T> set;
	private Map<T, ItemAction> itemActions;
	
	private boolean locked = false;
	
	public ConcurrentSet() {
		super();
		
		set = new HashSet<T>();
		itemActions = new HashMap<T, ItemAction>();
	}
	
	public void add(T t) {
		if(!locked) {
			set.add(t);
		} else {
			itemActions.put(t, ItemAction.ADD_ITEM);
		}
	}
	
	public void remove(T t) {
		if(!locked) {
			set.remove(t);
		} else {
			itemActions.put(t, ItemAction.REMOVE_ITEM);
		}
	}
	
	public Set<T> lock() {
		locked = true;
		
		return set;
	}
	
	public void unlock() {
		locked = false;
		
		if(!itemActions.isEmpty()) {
			
			for(Entry<T, ItemAction> entry: itemActions.entrySet()) {
				
				ItemAction action = entry.getValue();
				
				if(ItemAction.ADD_ITEM.equals(action)) {
					set.add(entry.getKey());
				} else if(ItemAction.REMOVE_ITEM.equals(action)) {
					set.remove(entry.getKey());
				}
			}
			
			itemActions.clear();
		}
	}

	public Set<T> getSet() {
		return set;
	}
	
}