scalesliderrenderer.java

esri的ArcGIS Server超级学习模板程序（for java）

package com.esri.solutions.jitk.web.faces.renderkit.xml.ajax;


import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

import com.esri.adf.web.data.WebContext;
import com.esri.adf.web.data.WebMap;
import com.esri.adf.web.data.geometry.GeometryUtil;
import com.esri.adf.web.data.geometry.WebExtent;
import com.esri.adf.web.faces.component.MapControl;
import com.esri.adf.web.faces.renderkit.xml.ajax.AJAXRenderer;
import com.esri.adf.web.util.WebUtil;
import com.esri.adf.web.util.XMLUtil;
import com.esri.solutions.jitk.web.event.IScaleSliderConfig;


public class ScaleSliderRenderer implements AJAXRenderer {
	@SuppressWarnings("unchecked")
	public Class getControlClass() {
		return MapControl.class;
	}

	public Object getOriginalState(final UIComponent component) {
		// We want to save the state of the control before the main serious GIS actions start!
		Document xmlDoc = XMLUtil.newDocument();
    	renderSliderXML(XMLUtil.createElement(xmlDoc, "root", null, null), component);
    	return XMLUtil.transform(xmlDoc, null);
	}

	public void renderAjaxResponse(final FacesContext facesContext,
                                   final UIComponent component,
                                   final Object previousState,
                                   final boolean b,
                                   final Element parentElement) {
	    // Render the state of the control and compare if the previous state and new state are the same or not.
	    // If they are the same, the browser does not need to be updated.
	    // If they are different, then send the new state xml to the browser so that it can be updated.
	    Document xmlDoc = XMLUtil.newDocument();
	    renderSliderXML(XMLUtil.createElement(xmlDoc, "root", null, null), component);
	    XMLUtil.transform(xmlDoc, null);

	    parentElement.appendChild(parentElement.getOwnerDocument().importNode(xmlDoc.getElementsByTagName("root").item(0).getFirstChild(), true));
  	}

	public void renderSliderXML(final Element parentElement, final UIComponent aComponent) {
		MapControl mapControl = (MapControl) aComponent;
	    WebContext webContext = WebUtil.getWebContext(mapControl);
	    WebMap webMap = webContext.getWebMap();
	    double mapScale = webMap.getMapScale();
	 
	    FacesContext facesContext = FacesContext.getCurrentInstance();    
	    IScaleSliderConfig ssb = (IScaleSliderConfig) facesContext.getApplication().createValueBinding("#{scaleSliderBB}").getValue(facesContext);
	   
	    Element anElement = XMLUtil.createElement("slider-update", null, parentElement);
	
		if (isInside(mapControl)) { // if extent inside valid bounds set current map scale
			anElement.setAttribute("mapUpdate", "true");				
		} else { 		 // if extent outside get valid scale from mapScale_ <= getMaxAllowedScale()
			anElement.setAttribute("mapUpdate", "false");	
		}
			
		anElement.setAttribute("mapscale-value", Long.toString(Math.round(mapScale)));
		anElement.setAttribute("minscale-value", Long.toString(Math.round(ssb.getMinScale())));
		anElement.setAttribute("maxscale-value", Long.toString(Math.round(ssb.getMaxScale())));
	}
  
	private boolean isInside(MapControl mapControl) {
	  	WebContext webContext = WebUtil.getWebContext(mapControl);
	  	WebMap webMap = webContext.getWebMap();
	    WebExtent webExtent = webMap.getCurrentExtent();
	    WebExtent fullExtent = webMap.getFullExtent();     	
	  
		com.esri.solutions.jitk.web.data.geometry.WebExtent newExtent = 
			new com.esri.solutions.jitk.web.data.geometry.WebExtent(webExtent); 				
		
		//Do not scale the map to an extent that is not supported by the horizon of the 
		//coordinate system, i.e. full extent
		if (GeometryUtil.inside(newExtent, fullExtent)) {			
			return true;
		} else { // if map scale not within bounds calculate maximum valid scale		
			return false;
		}
	}
  

}