IBM WebSphere Everyplace Access V5 Handbook for Developers and Administrators Volume IV: Advanced Topics

Chapter 3. Subscription-based notifications 83

Refer to Chapter 1, “Intelligent Notification Services” on page 1 for details about

how to create and configure Intelligent Notification Services users.

The following sections explain how to develop and deploy each component of

this sample scenario using IBM WebSphere Studio.

3.3 Content adapter

Before you develop a content adapter, you must understand how you will obtain

data from the information source. For purposes of this example, this section

contains four parts:

򐂰 Developing a sample content source program that feeds the content adapter.

򐂰 Deploying that sample content source program.

򐂰 Developing a sample content adapter.

򐂰 Deploying that sample content adapter.

3.3.1 Developing a content source program

The characteristics of this sample content source program are:

򐂰 The program monitors the HTTP service status of the determined servers

every five minutes.

򐂰 There is a properties file that contains the URL addresses of the servers to be

monitored. This file is read by the content source program.

򐂰 A server status string is generated by this program after each server is

monitored. The possible values for this string are:

– All servers are up.

– At least one server is down.

– All servers are down.

򐂰 Communication between the content source and the content adapter is

through sockets. A properties file contains the information that is needed to

establish this connection.

The steps to develop this sample program are:

1. Create a Java Project:

a. Open the IBM WebSphere Studio Site Developer and select File

→ New

→ Project.

b. Select Java from the left panel and Java Project from the right panel.

Click Next.

84 IBM WebSphere Everyplace Access V5, Volume IV: Advanced Topics

c. Enter a project name. In this example it is MonitoringContentFeed. Click

Next.

d. Define the Java build settings and click Finish.

2. Create a new package. In this example the package is

com.ibm.pvc.ins.sm.apps.

3. In the new package, create a new Java file for the content source. In this

example, the name of the Java file is MonitoringContentFeeder.java.

4. Import the required packages as shown in Example 3-1.

Example 3-1 Required packages for MonitoringContentFeeder class

import java.io.InputStream;

import java.io.IOException;

import java.io.OutputStreamWriter;

import java.util.PropertyResourceBundle;

import java.net.*;

5. Create a new class. Declare auxiliary variables for sockets communication,

properties file (fully qualified class name), and server status messages as

shown in Example 3-2.

Example 3-2 Auxiliary variables for MonitoringContentFeeder class

public class MonitoringContentFeeder {

public static String host;

public static int port;

private final static String propertiesFile = "MonitoringFeederProperties";

private final static String allUp = "All Servers are Up";

private final static String allDown = "All Servers are Down";

private final static String atLeastOneDown = "At least one server is Down";

6. Create a function that establishes a stream socket connection to the host

where the content adapter resides, and send the server status information

Chapter 3. Subscription-based notifications 85

through this connection as shown in Example 3-3. Information about socket

connection is read from a properties file.

Example 3-3 feedToContentAdapter method implementation

private static boolean feedToContentAdapter(String sfeeded) {

try {

PropertyResourceBundle pr =

(PropertyResourceBundle)PropertyResourceBundle.getBundle(propertiesFile);

host = pr.getString("MonitoringContentAdapter.host");

port =

Integer.parseInt(pr.getString("MonitoringContentAdapter.port"));

Socket socket = new Socket(host, port);

OutputStreamWriter out = new

OutputStreamWriter(socket.getOutputStream());

out.write(sfeeded,0,sfeeded.length()-1);

out.flush();

out.close();

} catch (UnknownHostException e) {

return false;

} catch (IOException e) {

return false;

}

return true;

}

7. In the main method, define an infinite loop with the following attributes:

a. Wait and sleep for five minutes so that the server is checked every five

minutes for a status change.

b. Read the properties file to obtain the URL addresses and the quantity of

servers that are monitored.

c. For each monitored server, try to establish an HTTP connection.

d. Depending on the HTTP connection results, set the server status

message. (One message status is generated for the whole group of

servers.) Send the server status message to the content adapter using the

function defined earlier. (In this example, it is feedToContentAdapter.)

86 IBM WebSphere Everyplace Access V5, Volume IV: Advanced Topics

Example 3-4 Main method of class MonitoringContentFeeder

public static void main(String[] args)

{

String monitoringServerURL;

InputStream connection;

System.out.println("Starting Monitoring Content Feeder....");

do {

String mssg = "ServerStatus: ";

int srvQuantity = 0;

int count = 0;

try {

Thread.sleep(300000);

PropertyResourceBundle pr =

(PropertyResourceBundle)PropertyResourceBundle.getBundle(propertiesFile);

srvQuantity = Integer.parseInt(pr.getString("ServersQty"));

for (int i=1;i<=srvQuantity;i++) {

monitoringServerURL = pr.getString("MonitoringServerURL"+i);

try {

connection = new URL(monitoringServerURL).openStream();

if (connection != null)

count++;

} catch (Exception e){

}

}

if (count == srvQuantity) {

mssg = mssg + allUp;

} else

if (count == 0) {

mssg = mssg + allDown;

} else {

mssg = mssg + atLeastOneDown;

}

mssg = mssg + System.getProperty("line.separator");

if (!feedToContentAdapter(mssg)) {

System.err.println("Content feed error.");

return;

}

System.out.println("Message: "+mssg);

} catch (Exception e) {

System.out.println(e.getMessage());

}

} while(true);

}