ZK Custom Pagination and Sorting

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.List;

import org.zkoss.lang.Strings;
import org.zkoss.zk.ui.event.Event;
import org.zkoss.zk.ui.event.EventListener;
import org.zkoss.zk.ui.ext.AfterCompose;
import org.zkoss.zul.Listbox;
import org.zkoss.zul.Listcell;
import org.zkoss.zul.Listhead;
import org.zkoss.zul.Listheader;
import org.zkoss.zul.Listitem;
import org.zkoss.zul.Paging;
import org.zkoss.zul.event.PagingEvent;


public class TagsContoller extends SimpleWindow implements AfterCompose {

  	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	private final String LST_TAGS = "lstTags";
	private final String PAG_TAGS = "pagTag";
	private String ASCENDING = "ascending";
	private String DESCENDING = "descending";
	private String NATURAL = "natural";
	private String DATE_FORMAT = "yyyy/MM/dd HH:mm:ss";
	private boolean ascending = true;
	Listhead listhead;
	Listbox lstTags;
	
	private String getHeaderLabel(String label){
		
		if(label != null && label.equalsIgnoreCase("Timestamp")){
        	return TagBlinkCache.TIMESTAMP_SEC_INDEX;
        }else if(label != null && label.equalsIgnoreCase("x")){
        	return TagBlinkCache.LOC_X_INDEX;
        }else if(label != null && label.equalsIgnoreCase("y")){
        	return TagBlinkCache.LOC_Y_INDEX;
        }else if(label != null && label.equalsIgnoreCase("z")){
        	return TagBlinkCache.LOC_Z_INDEX;
        }else if(label != null && label.equalsIgnoreCase("Exciter Id")){
        	return TagBlinkCache.STATION_ID_INDEX;
        }else{
        	return TagBlinkCache.TAG_ID_INDEX;
        }
	}
	public void redrawForAscDesc(String indexId){
		
        List<TagBlink> list1 = TagBlinkCache.getInstance().getList(indexId);
        
		Paging pag = getPaging(PAG_TAGS);
		pag.setTotalSize(list1.size());
		
		final int PAGE_SIZE = pag.getPageSize();
		
		// Show Listbox with first PAGE_SIZE		
		redraw(0, PAGE_SIZE,list1,true);
		pag.setActivePage(0);
	}
	public void onSortEventListener(Event event) {
        
            final Listheader lh = (Listheader) event.getTarget();
            final String sortDirection = lh.getSortDirection();
            String indexId = "";
            if (ASCENDING.equals(sortDirection)) {
            	ascending = true;
            	indexId = getHeaderLabel(lh.getLabel());
            	redrawForAscDesc(indexId);
            } else if (DESCENDING.equals(sortDirection) || NATURAL.equals(sortDirection) || Strings.isBlank(sortDirection)) {
            		ascending = false;
            		indexId = getHeaderLabel(lh.getLabel());
            		redrawForAscDesc(indexId);
            }
    }
    
	@SuppressWarnings("unchecked")
	public void afterCompose() {
		lstTags = getListbox(LST_TAGS);
		Listhead listhead = lstTags.getListhead();
        List<Listheader> list = listhead.getChildren();
 
        for (Object object : list) {
            if (object instanceof Listheader) {
                Listheader lheader = (Listheader) object;
               
                if (lheader.getSortAscending() != null || lheader.getSortDescending() != null) {
 
                    lheader.addEventListener("onSort", new EventListener() {
            			public void onEvent(Event event) {
            				onSortEventListener(event);
            			}
            		});
                }
            }
        }
		
		String indexId = "tagId_INDEX";
		final List<TagBlink> list1 = TagBlinkCache.getInstance().getList(indexId);
		
		Paging pag = getPaging(PAG_TAGS);
		pag.setTotalSize(list1.size());
		
		final int PAGE_SIZE = pag.getPageSize();
		
		// Show Listbox with first PAGE_SIZE		
		redraw(0, PAGE_SIZE,list1,false);

		pag.addEventListener(org.zkoss.zul.event.ZulEvents.ON_PAGING, new EventListener() {
			public void onEvent(Event event) {
				PagingEvent pe = (PagingEvent) event;
				int pgno = pe.getActivePage();
				int ofs = pgno * PAGE_SIZE;
				// Redraw current paging
				redraw(ofs, PAGE_SIZE,list1,false);
			}
		});
	}
	
	private void redraw(int firstResult, int maxResults, List<TagBlink> list1,boolean sorting) {
		
		RangeFinder.Range range;
		List<TagBlink> subList;
		synchronized (list1) {
			range = RangeFinder.findRange(list1, firstResult,
					maxResults, ascending);
			try {
				subList = list1.subList(range.getFromIndex(), range.getToIndex());
			} catch (IndexOutOfBoundsException e) {
				subList = new ArrayList<TagBlink>();
			}
		}
		
		Listbox lst = getListbox(LST_TAGS);
		lst.getItems().clear();

		SimpleDateFormat df = new SimpleDateFormat(DATE_FORMAT);
		
		for (TagBlink tagBlink : subList) {
			
			Listitem li = new Listitem();
			li.setValue(tagBlink);
			li.appendChild(new Listcell("" + tagBlink.getSource()));
			li.appendChild(new Listcell(tagBlink.getFormat()));
			li.appendChild(new Listcell(tagBlink.getId()));
			li.appendChild(new Listcell(tagBlink.getX()+""));
			li.appendChild(new Listcell(tagBlink.getY()+""));
			li.appendChild(new Listcell(tagBlink.getZ()+""));
			li.appendChild(new Listcell(tagBlink.getBattery()+""));
			li.appendChild(new Listcell(tagBlink.getStationId()+""));
			li.appendChild(new Listcell(tagBlink.getStatus()+""));
			Date date = new Date(tagBlink.getTimestampMillis());
			li.appendChild(new Listcell(df.format(date)));
			lst.appendChild(li);
		}
	}
}

<?xml version="1.0" encoding="UTF-8"?>
<?page id="zkHome" title="ZK Demo"?>
<?taglib uri="http://www.zkoss.org/dsp/web/core" prefix="c"?>
<?init class="org.zkoss.zkplus.databind.AnnotateDataBinderInit" arg0="./cTags"?>

<zk xmlns="http://www.zkoss.org/2005/zul">

<style src="../style/zls-console.css"></style>
<style>
	div.z-grid-body{
		background: white; border: 0; overflow: auto; width: 100%;
	}
	
</style>

	
<window width="100%" id="cTags"
	border="none" use="TagsContoller"
	xmlns:zk="http://www.zkoss.org/2005/zul"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:n="http://www.zkoss.org/2005/zk/native"
	xsi:schemaLocation="http://www.zkoss.org/2005/zul http://www.zkoss.org/2005/zul/zul.xsd">
	<n:script type="text/javascript"><![CDATA[
			function screenResolution(){
				if(screen.height == 1024)
					zk.Widget.$(jq('$lstTags')[0]).setStyle('height:710px');
				else if(screen.height == 864)
					zk.Widget.$(jq('$lstTags')[0]).setStyle('height:635px');
				else if(screen.height == 768)
					zk.Widget.$(jq('$lstTags')[0]).setStyle('height:540px');
				else if(screen.height == 600)
					zk.Widget.$(jq('$lstTags')[0]).setStyle('height:375px');	
						
	        }
        ]]>
  		</n:script>
	<attribute name="onCreate"><![CDATA[
      Clients.evalJavaScript("screenResolution()");        
    ]]></attribute>
    
		<toolbar align="end"><div height="23px">
		</div></toolbar> 
	<div>
			<zk:listbox id="lstTags" vflex="true" style="height:540px" hflex="true">
				<zk:listhead sizable="true">
					<zk:listheader label="Source"/>
					<zk:listheader label="Format"/>
					<zk:listheader label="Tag Id" sort="auto" />
					<zk:listheader label="x" sort="auto"  width="5%"/>
					<zk:listheader label="y" sort="auto"  width="5%"/>
					<zk:listheader label="z" sort="auto"  width="5%"/>
					<zk:listheader label="Battery" width="10%"/>
					<zk:listheader label="Exciter Id" sort="auto"  width="10%"/>
					<zk:listheader label="Status" width="10%"/>
					<zk:listheader label="Timestamp" sort="auto" />
				</zk:listhead>
			</zk:listbox>
			<zk:paging id="pagTag" pageSize="25"/>
	</div>	
</window>	
</zk>