public void validate() throws MissingCredentialException {
		if (getUserName() == null || getUserName() == "") {
			throw new MissingCredentialException("username can't be empty");
		}
		if (getPassword() == null || getPassword() == "") {
			throw new MissingCredentialException("password can't be empty");
		}
		if (this.signature == null || this.signature == "") {
			throw new MissingCredentialException("signature can't be empty");
		}
		if (getApplicationId() == null || getApplicationId() == "") {
			throw new MissingCredentialException("applicationId can't be empty");
		}
	}