/**
* This method returns a list of urls for retrieving the individual layers of the map. It will
* coalesce adjacent layers into a single request, when possible.
*
* @param layerList Element parent node to the list of layer Elements within the ViewContext
* @param layers String[] of layer names
* @param bbox Envelope spatial extent of the map image
* @param width x-dimension of the map image
* @param height y-dimension of the map image
* @param format String mime-type of the map image
* @return List of urls for get map requests
* @ssdd
*/
private List<String> getLayerRequests(
Element layerList, String[] layers, Envelope bbox, int width, int height, String format) {
List<String> requests = new ArrayList<String>();
String lastServer = null;
for (Element elem : DOMUtils.getChildren(layerList, "Layer")) {
// get layer name
String name = DOMUtils.getChildText(elem, "Name");
// is layer in list of requested layers?
if (!contains(layers, name)) continue;
// is layer visible?
if (Coerce.toBoolean(elem.getAttribute("hidden"))) continue;
// get href to layer's service
Node server = DOMUtils.getChild(elem, "Server");
Element or = DOMUtils.getChild(server, "OnlineResource");
String href = or.getAttribute("xlink:href");
if (href.equals(lastServer)) {
String layerNames = requests.remove(requests.size() - 1);
layerNames += "," + name;
requests.add(layerNames);
} else {
lastServer = href;
requests.add(getMapRequest(href, name, bbox, width, height, format));
}
}
return requests;
}
