Context (milky-common 1.0.13 API)

All Superinterfaces:

Map<K,V>

All Known Implementing Classes:

ContextMap
```
public interface Context<K,V>
extends Map<K,V>
```
执行上下文，用来在不同的Command间传递信息。 Map后面可以考虑使用AttributeMap代替。

Nested Class Summary
- Nested classes/interfaces inherited from interface java.util.Map
  Map.Entry<K extends Object,V extends Object>

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Logger`	`logger()`	This method provider a `Logger` utililies for user can't construct a logger or try to log pipeline context message to one logger file.
`<T extends V> T`	`retrieve(K key)`	That method enhances the `Map.get(Object)` method that helps users avoid the redundant code of type cast/checking when assignments are already known.

Methods inherited from interface java.util.Map
clear, compute, computeIfAbsent, computeIfPresent, containsKey, containsValue, entrySet, equals, forEach, get, getOrDefault, hashCode, isEmpty, keySet, merge, put, putAll, putIfAbsent, remove, remove, replace, replace, replaceAll, size, values

- Method Detail
  - retrieve
```
<T extends V> T retrieve(K key)
```
    That method enhances the Map.get(Object) method that helps users avoid the redundant code of type cast/checking when assignments are already known.
    It throws ClassCastException if types are not assignable.
    
    Type Parameters:
    
    T - the target assignment type
    
    Parameters:
    
    key - the key whose associated value is to be returned
    
    Returns:
    
    the value to which the specified key is mapped, or null if this map contains no mapping for the key
    
    See Also:
    
    Map.get(Object)
  - logger
```
Logger logger()
```
    This method provider a Logger utililies for user can't construct a logger or try to log pipeline context message to one logger file.
    
    Returns:
    
    logger