PerformanceMonitorInterceptor is a very basic and simple way to monitor the execution of our method time. However, most of the time we would need more a controlled way to monitor the method and its parameters. For that, we can implement our custom interceptor, either by extending AbstractMonitoringInterceptor or writing around advice or a custom annotation. Here we will write a custom interceptor extending AbstractMonitoringInterceptor.

Let's extend the AbstractMonitoringInterceptor class and override the invokeUnderTrace method to log the start, end, and duration of a method. We can also log a warning if the method execution lasts more than 5 milliseconds. The following is the code sample for the custom monitoring interceptor:

public class CustomPerformanceMonitorInterceptor extends AbstractMonitoringInterceptor {
    
    private static final long serialVersionUID = -4060921270422590121L;
    public CustomPerformanceMonitorInterceptor() {
    }
 
    public CustomPerformanceMonitorInterceptor(boolean 
    useDynamicLogger) {
            setUseDynamicLogger(useDynamicLogger);
    }
 
    @Override
    protected Object invokeUnderTrace(MethodInvocation invocation, Log 
    log) 
      throws Throwable {
        String name = createInvocationTraceName(invocation);
        long start = System.currentTimeMillis();
        log.info("Method " + name + " execution started at:" + new 
        Date());
        try {
            return invocation.proceed();
        }
        finally {
            long end = System.currentTimeMillis();
            long time = end - start;
            log.info("Method "+name+" execution lasted:"+time+" ms");
            log.info("Method "+name+" execution ended at:"+new Date());
             
            if (time > 5){
                log.warn("Method execution took longer than 5 ms!");
            } 
        }
    }
}

Every other step we saw in the basic PerformanceMonitorInterceptor would be same, just replace PerformanceMonitorInterceptor with CustomPerformanceMonitorInterceptor.

The following output is generated:

2018-02-07 22:23:44 INFO TransferServiceImpl:32 - Method com.packt.springhighperformance.ch03.bankingapp.service.TransferService.transfer execution lasted:5001 ms
2018-02-07 22:23:44 INFO TransferServiceImpl:33 - Method com.packt.springhighperformance.ch03.bankingapp.service.TransferService.transfer execution ended at:Wed Feb 07 22:23:44 EST 2018
2018-02-07 22:23:44 WARN TransferServiceImpl:36 - Method execution took longer than 5 ms!