StorageUsageRefresher (ambry-api 0.3.442 API)

```
public interface StorageUsageRefresher
```
An interface to initialize the storage usage of each container and save them in memory. It should also refresh the in memory cache if there is any change of storage usage.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static interface StorageUsageRefresher.Listener
A listener interface registered with StorageUsageRefresher.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.util.Map<java.lang.String,java.util.Map<java.lang.String,java.lang.Long>>`	`getContainerStorageUsage()`	Return the current storage usage for each container.
`void`	`registerListener(StorageUsageRefresher.Listener listener)`	Register your listener to `StorageUsageRefresher`.

- Method Detail
  - getContainerStorageUsage
```
java.util.Map<java.lang.String,java.util.Map<java.lang.String,java.lang.Long>> getContainerStorageUsage()
                                                                                                             throws java.lang.Exception
```
    Return the current storage usage for each container. The returned map should be structured as such: The key of the map is the account id in string format and the value of the map is the storage usage of each container under this account. The container usage map's key is the container is in string format, and the value is storage usage of this container.
    
    Returns:
    
    The current storage usage for each container.
    
    Throws:
    
    java.lang.Exception
  - registerListener
```
void registerListener(StorageUsageRefresher.Listener listener)
```
    Register your listener to StorageUsageRefresher. A refresher should only have one callback and it can't be registered multiple times.
    
    Parameters:
    
    listener - The listener to register.