package chat.server.im;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

import com.google.protobuf.GeneratedMessage;

public class WFCMessageParseTable {

	private static WFCMessageParseTable instance;
	private Map<Class<? extends GeneratedMessage>, Method> clazzMethodMap;
	
	public static synchronized WFCMessageParseTable getInstance() {
		if (instance == null) {
			instance = new WFCMessageParseTable();
		}
		
		return instance;
	}
	
	private WFCMessageParseTable() {
		clazzMethodMap = new HashMap<Class<? extends GeneratedMessage>, Method>();
	}
	
	public Method getMethod(Class<? extends GeneratedMessage> clazz) {
		if (clazz == null) {
			return null;
		}
		
		Method result = clazzMethodMap.get(clazz);
		
		if (result == null) {
			synchronized (this) {
				result = clazzMethodMap.get(clazz);
				
				if (result == null) {
					result = doGetMethod(clazz);
					clazzMethodMap.put(clazz, result);
				}
			}
		}
		
		return result;
	}

	private Method doGetMethod(Class<? extends GeneratedMessage> clazz) {
		try {
			Method method = clazz.getMethod("parseFrom", byte[].class);
			return method;
		} 
		catch (Exception e) {
		} 
		
		return null;
	}
	
}