Shapefile layers as variable in WPS process

Question

i created a new WPS process. I have a class with method and class with implementation into GeoServer.

@DescribeProcess(title="overlayWPS", description="Creates buffer around point and overlays it with polygon layer. Returns areas of overlay.")
public class OverlayPolygons implements GeoServerProcess {

    @DescribeResult(name="result", description="output result")
    public String execute() throws IOException{
        Process p = new Process();
        return p.overlayPolygons();
    }    
}

i would like to put input shapefiles as parameter which can user change in wps requiest builder, now i have static URL to specific shp

String overlayPolygons() throws IOException {

        String areas = "Object : Area of overlay";

        ShapefileDataStore sfds;
        sfds = new ShapefileDataStore(new URL("file:///F:\\GeoServer285\\data_dir\\data\\test_data\\lesy_cr.shp"));

        SimpleFeatureSource fs;
        fs = sfds.getFeatureSource("lesy_cr");

        ShapefileDataStore sfds2;
        sfds2 = new ShapefileDataStore(new URL("file:///F:\\GeoServer285\\data_dir\\data\\test_data\\chranene_uzemi_cr.shp"));

        SimpleFeatureSource fs2;
        fs2 = sfds2.getFeatureSource("chranene_uzemi_cr");

I found out there must be some @DescribeParameter annotation, but i cant figure out how to use it at all.

Answer 1

The best example of WPS processes is the GeoTools' tutorial. Input parameters are declared as parameters to the (static) process method and need to be annotated with @DescribeParameter that allows you to specify a name, type and optionally minimum and maximum number of occurrences etc.

Rather than specifying a Shapefile explicitly, you probably want to use a SimpleFeatureCollection which would allow you to set the process up with any GeoServer vector data source.

Here is an example:

@DescribeProcess(title = "Table Join", description = "Join two FeatureCollections based on a Join (including optional alias)")
  @DescribeResult(description = "the two collections joined together.")

  static public SimpleFeatureCollection joinTables(
      @DescribeParameter(name = "target", description = "the collection to be joined to", min = 1) SimpleFeatureCollection target,
      @DescribeParameter(name = "source", description = "the collection to be joined", min = 1, meta = {
          "mimeTypes=text/csv" }) SimpleFeatureCollection joinSource,
      @DescribeParameter(name = "join", description = "the Join element that describes the relationship between the collections", min = 1, meta = {
          "mimeTypes=text/xml" }) String joinXML) {
    Join join = null;
    join = parseJoinXML(joinXML);

    if (target == null) {
      throw new IllegalArgumentException("target can not be null");
    }
    if (joinSource == null) {
      throw new IllegalArgumentException("source can not be null");
    }
    if (join == null || join.getFilter() == null) {
      throw new IllegalArgumentException("join can not be null");
    }