org.zkoss.web.util.resource
Class ResourceLoader

java.lang.Object
  org.zkoss.web.util.resource.ResourceLoader

All Implemented Interfaces:

Loader

public abstract class ResourceLoader
extends java.lang.Object
implements Loader

A semi-implemented loader to used with ResourceCaches.get(org.zkoss.util.resource.ResourceCache, javax.servlet.ServletContext, java.lang.String, java.lang.Object) to retrieve servlet resources.

Author:

tomyeh

Constructor Summary

protected

ResourceLoader()

Method Summary

long	getLastModified(java.lang.Object src) Returns the last modified time, or -1 if reload is required or not exists.
java.lang.Object	load(java.lang.Object src) Loads the resource.
protected abstract java.lang.Object	parse(java.lang.String path, java.io.File file, java.lang.Object extra) Parses the specified file and returns the result which will be stored into the cache (ResourceCaches.get(org.zkoss.util.resource.ResourceCache, javax.servlet.ServletContext, java.lang.String, java.lang.Object)).
protected abstract java.lang.Object	parse(java.lang.String path, java.net.URL url, java.lang.Object extra) Parses the specified URL and returns the result which will be stored into the cache (ResourceCaches.get(org.zkoss.util.resource.ResourceCache, javax.servlet.ServletContext, java.lang.String, java.lang.Object)).
boolean	shallCheck(java.lang.Object src, long expiredMillis) Returns whether to call Loader.getLastModified(java.lang.Object).

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ResourceLoader

protected ResourceLoader()

Method Detail

parse

protected abstract java.lang.Object parse(java.lang.String path,
                                          java.io.File file,
                                          java.lang.Object extra)
                                   throws java.lang.Exception

Parses the specified file and returns the result which will be stored into the cache (ResourceCaches.get(org.zkoss.util.resource.ResourceCache, javax.servlet.ServletContext, java.lang.String, java.lang.Object)).

Deriving must override this method.

Parameters:

extra - the extra paramter passed from ResourceCaches.get(org.zkoss.util.resource.ResourceCache, javax.servlet.ServletContext, java.lang.String, java.lang.Object).

Throws:

java.lang.Exception

parse

protected abstract java.lang.Object parse(java.lang.String path,
                                          java.net.URL url,
                                          java.lang.Object extra)
                                   throws java.lang.Exception

Parses the specified URL and returns the result which will be stored into the cache (ResourceCaches.get(org.zkoss.util.resource.ResourceCache, javax.servlet.ServletContext, java.lang.String, java.lang.Object)).

Deriving must override this method.

Parameters:

extra - the extra paramter passed from ResourceCaches.get(org.zkoss.util.resource.ResourceCache, javax.servlet.ServletContext, java.lang.String, java.lang.Object).

Throws:

java.lang.Exception

shallCheck

public boolean shallCheck(java.lang.Object src,
                          long expiredMillis)

Description copied from interface: Loader

Returns whether to call Loader.getLastModified(java.lang.Object). If false, it assumes the current cached content is up-to-date.

Specified by:

shallCheck in interface Loader

expiredMillis - how many milli-seconds are expired after the last check. In most cases, just return true if expiredMillis > 0

getLastModified

public long getLastModified(java.lang.Object src)

Description copied from interface: Loader

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

Specified by:

getLastModified in interface Loader

load

public java.lang.Object load(java.lang.Object src)
                      throws java.lang.Exception

Description copied from interface: Loader

Loads the resource.

Specified by:

load in interface Loader

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)