# Logging

{% hint style="warning" %}
**This is the manual for older MicroStream versions (Version < 5.0).**

**The new documentation (Version >= 5.0) is located at:**

[https://docs.microstream.one/](https://docs.microstream.one/manual)
{% endhint %}

Another predefined logic layer is for logging purposes. Since there is a myriad of loggers out there, MicroStream doesn't provide any special adapter, but a generic type which can be used to adapt to the logging framework of your choice.

Just create a class and implement `EntityLogger`, and you are good to go.

```java
public class JulLogger implements EntityLogger
{
	@Override
	public void afterUpdate(
		final Entity identity, 
		final Entity data, 
		final boolean successful)
	{
		Logger.getLogger(identity.getClass().getName())
			.info("Entity updated");
	}
}
```

Additional to `afterUpdate` there are further hooks:

* `entityCreated`
* `afterRead`
* `beforeUpdate`

Now just add the logger when creating entities:

```java
JulLogger logger = new JulLogger();

Person john = PersonCreator.New()
	.addLayer(logger)
	.firstName("John")
	.lastName("Doe")
	.create();
```

When you call

```java
PersonUpdater.setLastName(john, "Smith");
```

the logger's output is

```
Oct 15, 2019 11:17:53 AM JulLogger afterUpdate
INFO: Entity updated
```


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