org.zkoss.util.resource

Interface Loader<K,V>

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

Method Summary

Modifier and Type	Method and 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)