import java.util.Collections;
import java.util.HashMap;
import java.util.Map;

/**
 * 
 * This class maintains in memory cache. 
 * @author kamalmeet
 *
 */

public class CommonCache {
	
	//The map that will store the cache
	private static Map<String, Object> cache=null;
	
	private static CommonCache reportCache=new CommonCache();
	
	/**
	 * Make sure the class is singleton so only one instance is shared by all. 
	 */
	private CommonCache()
	{
		cache=Collections.synchronizedMap(new HashMap<String, Object>());
	}
	
	/**
	 * Get the singleton instance.
	 * @return
	 */
	public static CommonCache getInstance()
	{
		return reportCache;
	}
	
	/**
	 * Add new element to cache.
	 * @param key
	 * @param value
	 */
	public void addToCache(String key, Object value)
	{
		cache.put(key, value);
	}
	
	/**
	 * Remove an element from cache.
	 * @param key
	 */
	public void removeFromCache(String key)
	{
		cache.remove(key);
	}
	
	/**
	 * Clean up cache.
	 */
	public void invalidateCache()
	{
		cache=Collections.synchronizedMap(new HashMap<String, Object>());
	}
	
	/**
	 * Get the element from cache.
	 * @param key
	 * @return
	 */
	public Object getFromCache(String key)
	{
		if(cache.containsKey(key))
			return cache.get(key);
		else
			return null;
	}
	
}