My proof of concept that Java on the server, along with RESTful APIs, can be an impressive and easy way of managing business applications (this uses a standard Domino Java Code element with an XPage as the front-end). Package is defined with a single class and single (static) method, to return the data from a simple REST call, fully on the serve…

CustRestConsumer.java

package com.eric.restful;
 
import java.net.URL;
import java.net.URLConnection;
import java.io.BufferedReader;
import com.google.gson.*;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.IOException;
import java.net.MalformedURLException;
import org.apache.commons.validator.routines.*;
 
/**
 * Class with a single, public, static method to provide a  REST consumer
 * which returns data as a JsonObject.
 * 
 * @author Eric McCormick, @edm00se
 * 
 */
public class CustRestConsumer {
	/**
	 * Method for receiving HTTP JSON GET request against a RESTful URL data source.
	 * 
	 * @param myUrlStr the URL of the REST endpoint
	 * @return JsonObject containing the data from the REST response.
	 * @throws IOException
	 * @throws MalformedURLException
	 * @throws ParseException 
	 */
	public static JsonObject GetMyRestData( String myUrlStr ) throws IOException, MalformedURLException {
		JsonObject myRestData = new JsonObject();
		try{
			
			UrlValidator defaultValidator = new UrlValidator();
			if(defaultValidator.isValid(myUrlStr)){
				
				URL myUrl = new URL(myUrlStr);
				URLConnection urlCon = myUrl.openConnection();
				urlCon.setConnectTimeout(5000);
				InputStream is = urlCon.getInputStream();
				InputStreamReader isR = new InputStreamReader(is);
				BufferedReader reader = new BufferedReader(isR);
				StringBuffer buffer = new StringBuffer();
				String line = "";
				while( (line = reader.readLine()) != null ){
					buffer.append(line);
				}
				reader.close();
				JsonParser parser = new JsonParser();
				myRestData = (JsonObject) parser.parse(buffer.toString());
				
				return myRestData;
				
			}else{
				myRestData.addProperty("error", "URL failed validation by Apache Commmons URL Validator");
				return myRestData;
			}
		}catch( MalformedURLException e ){
			e.printStackTrace();
			myRestData.addProperty("error", e.toString());
			return myRestData;
		}catch( IOException e ){
			e.printStackTrace();
			myRestData.addProperty("error", e.toString());
			return myRestData;
		}
	}
}

demo.xsp.xml

<?xml version="1.0" encoding="UTF-8"?>
<xp:view
	xmlns:xp="http://www.ibm.com/xsp/core">
	<xp:this.beforePageLoad><![CDATA[#{javascript://import Java package
importPackage(com.eric.restful);
 
var urlStr = "http://ajax.googleapis.com/ajax/services/feed/load?v=1.0&num=5&q=";
urlStr += "http://www.npr.org/rss/rss.php?id=1001";
var myStuff:JsonObject = CustRestConsumer.GetMyRestData(urlStr);
 
viewScope.myResp = fromJson(myStuff);}]]></xp:this.beforePageLoad>
	<xp:dataTable
		id="dataTable1"
		rows="30"
		var="rowData"
		indexVar="rowCount">
		<xp:this.value><![CDATA[#{javascript:var obj = viewScope.get("myResp");
return obj.responseData.feed.entries;}]]></xp:this.value>
		<xp:column
			id="column1">
			<xp:this.facets>
				<xp:panel
					xp:key="header"
					tagName="h1">
					<xp:link
						escape="true"
						id="link1">
						<xp:this.text><![CDATA[#{javascript:var obj = viewScope.get("myResp");
	return obj.title;}]]></xp:this.text>
						<xp:this.value><![CDATA[#{javascript:var obj = viewScope.get("myResp");
	return obj.link;}]]></xp:this.value>
					</xp:link>
				</xp:panel>
			</xp:this.facets>
		</xp:column>
		<xp:column
			id="column2">
			<xp:panel
				tagName="h3">
				<xp:link
					escape="true"
					id="link2"
					text="#{javascript:rowData.title}"
					value="#{javascript:rowData.link}">
				</xp:link>
			</xp:panel>
			<xp:br></xp:br>
			<xp:text
				escape="false"
				id="computedField2"
				value="#{javascript:rowData.content}">
			</xp:text>
			<xp:br></xp:br>
		</xp:column>
		<xp:column
			id="column3">
			<xp:text
				escape="true"
				id="computedField3"
				value="#{javascript:rowData.publishedDate}">
			</xp:text>
		</xp:column>
	</xp:dataTable>
</xp:view>