org.zkoss.util.resource
Interface Loader

All Known Implementing Classes:

AbstractLoader, ContentLoader

public interface Loader

A loader that could load a resource to another format. It is mainly designed to work with ResourceCache.

Author:

tomyeh

Nested Class Summary

static class

Loader.Resource Represents the more information about an object loaded by load(java.lang.Object).

Method Summary

long	getLastModified(Object src) Returns the last modified time, or -1 if reload is required or not exists.
Object	load(Object src) Loads the resource.
boolean	shallCheck(Object src, long expiredMillis) Returns whether to call getLastModified(java.lang.Object).

Method Detail

shallCheck

boolean shallCheck(Object src,
                   long expiredMillis)

Returns whether to call getLastModified(java.lang.Object). 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(Object src)

Returns the last modified time, or -1 if reload is required or not exists.

load

Object load(Object src)
            throws 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:

Exception - you might throw any exception which will be passed back to the caller of ResourceCache.get(java.lang.Object)