org.springframework.beans.support.RefreshablePagedListHolder Maven / Gradle / Ivy
/*
* Copyright 2002-2005 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.beans.support;
import java.util.Locale;
import org.springframework.beans.BeanUtils;
/**
* RefreshablePagedListHolder is a PagedListHolder subclass with reloading capabilities.
* It automatically re-requests the List from the source provider, in case of Locale or
* filter changes.
*
* Data binding works just like with PagedListHolder. The locale can be specified in
* Locale's toString syntax, e.g. "locale=en_US". The filter object can be of any
* custom class, preferably a bean for easy data binding from a request. An instance
* will simply get passed through to PagedListSourceProvider.loadList. A filter property
* can be specified via "filter.myFilterProperty", for example.
*
*
The scenario in the controller could be:
*
* RefreshablePagedListHolder holder = request.getSession("mySessionAttr");
* if (holder == null) {
* holder = new RefreshablePagedListHolder();
* holder.setSourceProvider(new MyAnonymousOrEmbeddedSourceProvider());
* holder.setFilter(new MyAnonymousOrEmbeddedFilter());
* request.getSession().setAttribute("mySessionAttr", holder);
* }
* holder.refresh(false);
* BindException ex = BindUtils.bind(request, listHolder, "myModelAttr");
* return ModelAndView("myViewName", ex.getModel());
*
* ...
*
* private class MyAnonymousOrEmbeddedSourceProvider implements PagedListSourceProvider {
* public List loadList(Locale locale, Object filter) {
* MyAnonymousOrEmbeddedFilter filter = (MyAnonymousOrEmbeddedFilter) filter;
* }
*
* private class MyAnonymousOrEmbeddedFilter {
* private String name = "";
* public String getName() {
* return name;
* public void setName(String name) {
* this.name = name;
* }
* }
*
*
* @author Jean-Pierre Pawlak
* @author Juergen Hoeller
* @since 24.05.2003
* @see org.springframework.beans.support.PagedListSourceProvider
* @see org.springframework.beans.propertyeditors.LocaleEditor
*/
public class RefreshablePagedListHolder extends PagedListHolder {
private PagedListSourceProvider sourceProvider;
private Locale locale;
private Locale localeUsed;
private Object filter;
private Object filterUsed;
/**
* Create a new list holder.
* You'll need to set a source provider to be able to use the holder.
* @see #setSourceProvider
*/
public RefreshablePagedListHolder() {
super();
}
/**
* Create a new list holder with the given source provider.
*/
public RefreshablePagedListHolder(PagedListSourceProvider sourceProvider) {
super();
this.sourceProvider = sourceProvider;
}
/**
* Set the callback class for reloading the List when necessary.
* If the list is definitely not modifiable, i.e. not locale aware
* and no filtering, use PagedListHolder.
* @see org.springframework.beans.support.PagedListHolder
*/
public void setSourceProvider(PagedListSourceProvider sourceProvider) {
this.sourceProvider = sourceProvider;
}
/**
* Return the callback class for reloading the List when necessary.
*/
public PagedListSourceProvider getSourceProvider() {
return sourceProvider;
}
/**
* Set the Locale that the source provider should use for loading the list.
* This can either be populated programmatically (e.g. with the request locale),
* or via binding (using Locale's toString syntax, e.g. "locale=en_US").
* @param locale the current Locale, or null
*/
public void setLocale(Locale locale) {
this.locale = locale;
}
/**
* Return the Locale that the source provider should use for loading the list.
* @return the current Locale, or null
*/
public Locale getLocale() {
return locale;
}
/**
* Set the filter object that the source provider should use for loading the list.
* This will typically be a bean, for easy data binding.
* @param filter the filter object, or null
*/
public void setFilter(Object filter) {
this.filter = filter;
}
/**
* Return the filter that the source provider should use for loading the list.
* @return the current filter, or null
*/
public Object getFilter() {
return filter;
}
/**
* Reload the underlying list from the source provider if necessary
* (i.e. if the locale and/or the filter has changed), and resort it.
* @param force whether a reload should be performed in any case
*/
public void refresh(boolean force) {
if (this.sourceProvider != null && (force ||
(this.locale != null && !this.locale.equals(this.localeUsed)) ||
(this.filter != null && !this.filter.equals(this.filterUsed)))) {
setSource(this.sourceProvider.loadList(this.locale, this.filter));
if (this.filter != null && !this.filter.equals(this.filterUsed)) {
this.setPage(0);
}
this.localeUsed = this.locale;
if (null != this.filter) {
this.filterUsed = BeanUtils.instantiateClass(this.filter.getClass());
BeanUtils.copyProperties(this.filter, this.filterUsed);
}
}
resort();
}
}