Use constant for MTU in the core resource and fixed potential field hiding in...

Use constant for MTU in the core resource and fixed potential field hiding in the basic coap resource

ws4d-jcoap/src/org/ws4d/coap/rest/BasicCoapResource.java

@@ -186,7 +186,7 @@ public class BasicCoapResource implements CoapResource {
 				response = channel.createNotification(obsRequest, CoapResponseCode.Content_205,
 						this.observeSequenceNumber, this.reliableNotification);
 			}
-			response.setPayload(getValue());
+			response.setPayload(this.getValue());
 			channel.sendNotification(response);
 		}
 	}

ws4d-jcoap/src/org/ws4d/coap/rest/CoreResource.java

@@ -23,6 +23,7 @@ import java.util.Map;
 import java.util.Set;
 
 import org.apache.log4j.Logger;
+import org.ws4d.coap.Constants;
 import org.ws4d.coap.messages.CoapMediaType;
 import org.ws4d.coap.tools.Encoder;
 
@@ -127,8 +128,8 @@ public class CoreResource extends BasicCoapResource {
 					returnString.append("\"");
 				}
 				// size estimate to be displayed?
-				// only display sz when larger than MTU; 1024 is MTU approx.
-				if (resource.getSizeEstimate() > 1024) { 
+				// only display sz when larger than MTU
+				if (resource.getSizeEstimate() > Constants.COAP_PAYLOAD_SIZE_MAX) { 
 					returnString.append(";sz=\"");
 					returnString.append(resource.getSizeEstimate());
 					returnString.append("\"");