Loader (zk 10.0.0 API)

All Known Implementing Classes:

AbstractLoader, ContentLoader, ExtendletLoader, ResourceLoader
```
public interface Loader<K,V>
```
A loader that could load a resource to another format. It is mainly designed to work with ResourceCache.

Author:

tomyeh

Nested Class Summary

Nested Classes
Modifier and Type Interface Description

static class Loader.Resource<V>
Represents the more information about an object loaded by load(K).

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`long`	`getLastModified(K src)`	Returns the last modified time, or -1 if reload is required or not exists.
`V`	`load(K src)`	Loads the resource.
`boolean`	`shallCheck(K src, long expiredMillis)`	Returns whether to call `getLastModified(K)`.

- Method Detail
  - shallCheck
```
boolean shallCheck(K src,
                   long expiredMillis)
```
    Returns whether to call getLastModified(K). If false, it assumes the current cached content is up-to-date.
    
    Parameters:
    
    expiredMillis - how many milli-seconds are expired after the last check. In most cases, just return true if expiredMillis > 0
  - getLastModified
```
long getLastModified(K src)
```
    Returns the last modified time, or -1 if reload is required or not exists.
  - load
```
V load(K src)
throws java.lang.Exception
```
    Loads the resource.
    The returned resource could be anything. It will be returned by ResourceCache.get(java.lang.Object). However, if you want to have more control (e.g., whether to cache), you can return an instance of Loader.Resource. Then, the return value of ResourceCache.get(java.lang.Object) will be Loader.Resource.resource.
    
    Returns:
    
    null if not found
    
    Throws:
    
    java.lang.Exception - you might throw any exception which will be passed back to the caller of ResourceCache.get(java.lang.Object)