ChangeWatcher (Helidon Project 2.6.9 API)

Type Parameters:

T - target of this change watcher, such as Path

All Known Implementing Classes:

EtcdWatcher, FileSystemWatcher
```
public interface ChangeWatcher<T>
```
Similar to a PollingStrategy a change watcher is used to identify a change and trigger reload of a ConfigSource. Where a polling strategy provides polling events to check for changes, change watcher is capable of identifying a change in the underlying target using other means.

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static interface ChangeWatcher.ChangeEvent<T>
A change event, carrying the target, type of change and time of change.

Method Summary

All Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`void`	`start(T target, Consumer<ChangeWatcher.ChangeEvent<T>> listener)`	Start watching a target for changes.
`default void`	`stop()`	Stop watching all targets for changes.
`Class<T>`	`type()`	Target supported by this change watcher.

- Method Detail
  - start
```
void start(T target,
           Consumer<ChangeWatcher.ChangeEvent<T>> listener)
```
    Start watching a target for changes. If a change happens, notify the listener.
    
    Parameters:
    
    target - target of this watcher, such as Path
    
    listener - listener that handles reloading of the resource being watched
  - stop
```
default void stop()
```
    Stop watching all targets for changes.
  - type
```
Class<T> type()
```
    Target supported by this change watcher.
    
    Returns:
    
    type supported