Implementing gs:Nearest WPS process from geoserver

Question

I am implementing gs:Nearest WPS process available in GeoServer using openlayers in OpenGeo Suite SDK. I am trying to implement this process as a openlayers plugin to hook into my custom web mapping application.Though there is many tutorial on how to implement JTS:Split and JTS:Buffer process there is no tutorial for any other wps process.This Process Require Feature collection or Vector Layer as a input.

Firebug Error Geometry.CLASS_NAME undefined i think this is because I am not able to collect all the features from the vector layer.

So How can I create a vector layer using OpenLayers.Layer.Vector????

var test = Ext.extend(gxp.plugins.Tool, {

ptype: 'myapp_test',

/** Initialization of the plugin */
init: function(target) {
    test.superclass.init.apply(this, arguments);

    // Create a WPSClient instance for use with the local GeoServer
    this.wpsClient = new OpenLayers.WPSClient({
        servers: {
            local: '/geoserver/wps'
        }
    });



    // Add action buttons when the viewer is ready
    target.on('ready', function() {
        // Get a reference to the vector layer from app.js
        this.layer = target.getLayerRecordFromMap({
            name: 'sketch',
            source: 'ol'
        }).getLayer();
      //I am not getting Feature Collection or can not create Vector layer
       this.layer2 = new OpenLayers.Layer.Vector("parks", {
                strategies: [new OpenLayers.Strategy.Fixed()],
                projection: new OpenLayers.Projection("EPSG:4326"),
                protocol: new OpenLayers.Protocol.WFS({
                    version: "1.1.0",
                    url:  "/geoserver/wfs",
                    featurePrefix: "medford",
                    featureType: "parks",
                    featureNS: "http://medford.opengeo.org"
                })
            });

        // Some defaults
        var actionDefaults = {
            map: target.mapPanel.map,
            enableToggle: true,
            toggleGroup: this.ptype,
            allowDepress: true
        };

        this.addActions([

            // Action for splitting by drawing a line
            new GeoExt.Action(Ext.apply({
                text: 'TEST',
                control: new OpenLayers.Control.DrawFeature(
                    this.layer, OpenLayers.Handler.Point, {
                    eventListeners: {
                        featureadded: this.nearf,
                        scope: this
                    }
                })
            }, actionDefaults))
        ]);
    }, this);
},

/** Handler function for splitting geometries */
   nearf: function(evt) {
 var wkt = new OpenLayers.Format.WKT();
 var pt=wkt.write(evt.feature);
//var f =JSON.parse(this.request.responseText);
//var myline = OpenLayers.Geometry.fromWKT('point(117 22)');
 var g = new OpenLayers.Format.GeoJSON(); 
 var f=g.read(this.request.responseText);
 this.wpsClient.execute({
                server: 'local',
                process: 'gs:Nearest',
                inputs: {features:this.layer2, point:pt},
                success: this.addResult
            });

},

/** Helper function for adding process results to the vector layer */
addResult: function(outputs) {
    alert('Hello World');
}
});

Ext.preg(test.prototype.ptype, test);

Answer 1

Not sure but try these:
- write the whole url
- change version to 1.0.0
- you need another parameter, the geometryName. It is the name of the geometrycolumn which contains the geometries, or if it is a shapefile, then it is called "the_geom"
- I think you don't need the featurePrefix

So like this:

 this.layer2 = new OpenLayers.Layer.Vector("parks", {
                strategies: [new OpenLayers.Strategy.Fixed()],
                projection: new OpenLayers.Projection("EPSG:4326"),
                protocol: new OpenLayers.Protocol.WFS({
                    version: "1.0.0", 
                    url:  "http://localhost:8080/geoserver/wfs",
                    //featurePrefix: "medford",
                    featureType: "parks",
                    featureNS: "http://medford.opengeo.org",
                    geometryName: "the_geom"
                })
            });

I hope it helps.
One more comment: I actually tried to implement the very same nearest process from geoserver but somehow I didn't succeed. So I simply sent a POST request to the server then it was ok. Here is some clue how this is done.
Please comment if it worked