Callback handler for RestDataSource

[Peter Odéus]

Calling setUpdateDataURL is a great way to get automatic updates in the background.

But how do I define a callback handler to do some tweaking of my own when the server responds?

[pboysen]

Use the transformResponse method

Here is an example that lets you add custom parameters on the post and lets you set up a listener when the server responds.

package edu.iastate.its.project.model.sharedwidgets.client;

import java.util.HashMap;

import com.smartgwt.client.data.DSRequest;
import com.smartgwt.client.data.DSResponse;
import com.smartgwt.client.data.RestDataSource;
import com.smartgwt.client.types.DSDataFormat;
import com.smartgwt.client.types.PromptStyle;

import edu.iastate.its.project.model.sharedwidgets.client.common.Util;

public class ProjectDataSource extends RestDataSource {
	private HashMap<String,String> params = new HashMap<String,String>();
	private DSListener listener;
	
	public ProjectDataSource(String context, String model, String xq) {
		setDataURL(Util.getDataURL());
		setDataFormat(DSDataFormat.XML);
		HashMap<String,String> map = new HashMap<String,String>();
		map.put("context", context);
		map.put("model", model);
		map.put("xq", xq);
		setDefaultParams(map);
	}
	
	public void addParameter(String name, String value) {
		params.put(name,value);
	}
	
	public DSListener getListener() {
		return listener;
	}

	public void setListener(DSListener listener) {
		this.listener = listener;
	}

	protected Object transformRequest(DSRequest request) {
		request.setParams(params);
		request.setUseSimpleHttp(true);
		request.setPromptStyle(PromptStyle.CURSOR);
		return super.transformRequest(request);
	}
	
	protected void transformResponse(DSResponse response, DSRequest request, Object data) {
		super.transformResponse(response, request, data);
		if (listener != null)
			listener.onData(response,request,data);
	}
}

[Isomorphic]

Thanks for posting that pboysen, that will be useful to a number of users.