noexcept: BTGattHandler::send*(): Fix BTDevice::getGattService(): Return zero sized array of BTGattServices on error

BTGattHandler::discoverCompletePrimaryServices():
- just discover the services and its characteristics and descriptors
- return bool, success of failor as returned by discovery methods (incl. their send*() command)

BTGattHandler::initClientGatt():
- clear services before retrieval and on error
- error response on
  - BTGattHandler::discoverCompletePrimaryServices() failure
  - no services
  - no GenericAccess services
- only return true and leave services if no error

BTDevice::getGattService():
- perform BTGattHandler::initClientGatt() error checks as well
- update method API doc, describing failure included no GenericAccess service

1 files changed, 13 insertions, 10 deletions

diff --git a/java/org/direct_bt/BTDevice.java b/java/org/direct_bt/BTDevice.java
index efa640f0..57187d6b 100644
--- a/java/org/direct_bt/BTDevice.java
+++ b/java/org/direct_bt/BTDevice.java
@@ -628,20 +628,23 @@ public interface BTDevice extends BTObject
     boolean isValid();
 
     /**
-     * Returns a list of shared BTGattService available on this device if successful,
-     * otherwise returns an empty list if an error occurred.
-     * <p>
+     * Returns a complete list of shared BTGattService available on this device,
+     * initially retrieved via GATT discovery.
+     *
+     * In case of transmission error, zero services or no GATT GenericAccess,
+     * method will return zero services indicating an error.
+     * In this case, user can assume that the connection is or will be disconnected.
+     *
      * Method is only functional on a remote BTDevice in {@link BTRole#Slave}, a GATT server,
      * i.e. the local BTAdapter acting as a {@link BTRole#Master} GATT client.
-     * </p>
-     * <p>
+     *
      * The HCI connectLE(..) or connectBREDR(..) must be performed first, see {@link #connectDefault()}.
-     * </p>
-     * <p>
-     * If this method has been called for the first time or no services have been detected yet:
+     *
+     * If this method has been called for the first time:
      * - the client MTU exchange will be performed
-     * - a list of GATTService will be retrieved
-     * </p>
+     * - a complete list of BTGattService inclusive their BTGattChar and BTGattDesc will be retrieved
+     * - the GATT GenericAccess is extracted from the services.
+     *
      * @since 2.4.0
      */
     List<BTGattService> getGattServices();