[Hypercup-users] How to use HyperCuP in your web application

[Slawek G. <sla...@de...>]

Hi,

Using HyperCuP implementation in your web application requires 3 steps 
in your java code, and set up topology.

The 3 java steps:
1) At the beginning of your work with HyperCuP you must initialize it.
In FOAFRealm and JeromeDL  projects we use an servlet, which has 
everything in method init.
The web applications use the servlet and method init is automatically 
invoked, if web.xml is configured correctly.

Simplified body of the method init:

public void init(ServletConfig config) throws ServletException {

//setting up the full address of the Web Service
        Configurator conf = 
HyperCuP.getInstance().registerServiceURL(props.getProperty("service_url"),"dfoaf"); 

//implementation of the local query must be given
        conf.registerLocalQuery(new LocalQueryImpl());
//file to contain configuration must be specified
        
conf.registerConnectionPropertiesFile("/tmp/hypercup-connections.xml");    
     }

2) Implementation of the local query.

LocalQuery interface contains only one method that has the following 
signature:
Serializable performQuery(Serializable query);

It defines the behavior of the peers in the HyperCuP network.
A Serializable argument lets us to pass parameters like Strings and many 
others.
The method is invoked on every peer in the HyperCuP network and every 
peer sends results.

Simplified example of implementation

  public class LocalQueryImpl implements LocalQuery {

  public Serializable performQuery(Serializable query) {
            //get user name and password from query
     String userData=(String)query;
    //an example of processing the data
  return authenticate(userData);
     }

3) Performing the query in web application:

In order to use the query your code should contain similar code:

                 LocalQueryImpl lqi=new LocalQueryImpl();
                 lqi.performQuery("us...@fo...::mypassword");

I think it is enough for the early beginning. I mentioned above that yon 
need to set up the topology.
Currently the topology is configured manually. I do not want to describe 
the steps of this process because
Pawel is going to change the code. Next week it will be able to do it in 
much easier way.

If you do not set up the topology, your application can work, but on 
only one machine. So, you can start your work asap.
Don't hesitate to ask me if you need more info, or just check FOAFRealm, 
JeromeDL projects source codes (located at sf.net)

Best,

Slawek