Guide to OpenIG
Chapter 12. Customizing OpenIG

The following sample filter sets an arbitrary header in the incoming request and outgoing response.

package com.example.filter;

// Java Standard Edition
import java.io.IOException;

// OpenIG Core Library
import org.forgerock.openig.filter.Chain;
import org.forgerock.openig.filter.GenericFilter;
import org.forgerock.openig.handler.HandlerException;
import org.forgerock.openig.heap.HeapException;
import org.forgerock.openig.heap.NestedHeaplet;
import org.forgerock.openig.http.Exchange;
import org.forgerock.openig.model.ModelException;

public class HelloWorldFilter extends GenericFilter {

    public String name;
    public String value;

    @Override
    public void filter(Exchange exchange, Chain chain)
            throws HandlerException, IOException {
        exchange.request.headers.put(name, value); // set header in request
        chain.handle(exchange); // pass to remaining filters & handler in chain
        exchange.response.headers.put(name, value); // set header in response
    }

    public static class Heaplet extends NestedHeaplet {

        @Override
        public Object create() throws HeapException, ModelException {
            HelloWorldFilter filter = new HelloWorldFilter();
            filter.name = config.get("name").required().asString(); // required
            filter.value = config.get("value").required().asString(); // req'd
            return filter;
        }
    }
}

The corresponding heap object configuration is as follows.

{
     "name": "HelloWorldFilter",
     "type": "com.example.filter.HelloWorldFilter",
     "config": {
         "name": "X-Hello",
         "value": "World" 
     }
}