package org.kuali.spring.proxy;
   
   import java.lang.reflect.Method;
   import java.lang.reflect.Modifier;
   
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   
   import net.sf.cglib.proxy.MethodInterceptor;
  import net.sf.cglib.proxy.MethodProxy;
  
  /**
   * 
   */
  public class TraceCallback implements MethodInterceptor {
  	private static final Logger logger = LoggerFactory.getLogger(TraceCallback.class);
  	private static final Object MUTEX = new Object();
  	long counter = 0;
  	private static final int LANGUAGE_MODIFIERS = Modifier.PUBLIC | Modifier.PROTECTED | Modifier.PRIVATE
  			| Modifier.ABSTRACT | Modifier.STATIC | Modifier.FINAL | Modifier.SYNCHRONIZED | Modifier.NATIVE;
  
  	@Override
  	public Object intercept(Object object, Method method, Object[] args, MethodProxy methodProxy) throws Throwable {
  		return intercept(new CallbackContext(object, method, args, methodProxy));
  	}
  
  	public Object intercept(CallbackContext context) throws Throwable {
  		long interceptCount = -1;
  		synchronized (MUTEX) {
  			interceptCount = this.counter++;
  		}
  		if (logger.isTraceEnabled()) {
  			logger.trace("Method Invocation Id=" + interceptCount + " Invoking {} parameters={}",
  					getString(context.getMethod()), context.getArgs());
  		}
  		Object result = context.getMethodProxy().invokeSuper(context.getObject(), context.getArgs());
  		if (logger.isTraceEnabled()) {
  			logger.trace("Method Invocation Id={} Result=[{}]", interceptCount, result);
  		}
  		return result;
  	}
  
  	protected String getTypeName(Class<?> type) {
  		if (type.isArray()) {
  			try {
  				Class<?> cl = type;
  				int dimensions = 0;
  				while (cl.isArray()) {
  					dimensions++;
  					cl = cl.getComponentType();
  				}
  				StringBuffer sb = new StringBuffer();
  				sb.append(cl.getName());
  				for (int i = 0; i < dimensions; i++) {
  					sb.append("[]");
  				}
  				return sb.toString();
  			} catch (Throwable e) { /* FALLTHRU */
  			}
  		}
  		return type.getSimpleName();
  	}
  
  	protected String getString(Method method) {
  		try {
  			StringBuffer sb = new StringBuffer();
  			int mod = method.getModifiers() & LANGUAGE_MODIFIERS;
  			if (mod != 0) {
  				sb.append(Modifier.toString(mod) + " ");
  			}
  			sb.append(getTypeName(method.getReturnType()) + " ");
  			sb.append(getTypeName(method.getDeclaringClass()) + ".");
  			sb.append(method.getName() + "(");
  			Class<?>[] params = method.getParameterTypes();
  			for (int j = 0; j < params.length; j++) {
  				sb.append(getTypeName(params[j]));
  				if (j < (params.length - 1))
  					sb.append(",");
  			}
  			sb.append(")");
  			Class<?>[] exceptions = method.getExceptionTypes();
  			if (exceptions.length > 0) {
  				sb.append(" throws ");
  				for (int k = 0; k < exceptions.length; k++) {
  					sb.append(exceptions[k].getName());
  					if (k < (exceptions.length - 1))
  						sb.append(",");
  				}
  			}
  			return sb.toString();
  		} catch (Exception e) {
  			return "<" + e + ">";
  		}
  	}
  
  }