$$ CancelHotel API: The API is implemented by the Hotel provider. It

accepts as input: ReservationNumber $($string$).$ It returns as output:

CancelationConfirmation $($True$/$False$),$ CancellationFees $($number$).$

$$ PayCreditCard API: The API is implemented by the Credit Card provider.

It accepts as input: CreditCardNumber $($string$),$ ExpirationDate $($date$),$

Amount $($number$).$ It returns as output: PaymentConfirmation

$($True$/$False$),$ Comment $($string$).$

TA also provides the following API to be consumed by third parties $($TA

Clients$).$ This API uses XML$.$

$$ BuyTravelPackageAPI: The API is implemented by the TA and consumed

by external partners. It accepts as input: From$-$Airport$-$Code $($string$),$

To$-$Airport$-$Code $($string$),$ Departure$-$Date $($date$),$ Return$-$Date $($date$),$

checkin $($date$),$ checkout $($date$).$ It returns as output:

ReservationConfirmation $($True$/$False$),$ ReservationNumber $($string$).$ It

returns as output: Airline, Departure$-$Time$-$From $($string$),$ Arrival$-$Time$-$

To $($string$),$ Departure$-$Time$-$To$($string$),$ Arrival$-$Time$-$From $($string$),$

Hotel$-$ID $($string$).$

For each API, provide the following:

a$.$ The protocol used $($GET or POST$).$ Explain in a couple of

sentences why is GET or POST more appropriate

b$.$ The URL $($you do not need to give actual URL. You can simply

put URL$1,$ URL$2,$ etc.$)$

c$.$ A short text description $($one or two sentences$)$ of what the

API does.

d$.$ The structure of the input message $($sent to the API as

request$)$ and output message $($result sent back by the API$).$

e$.$ Who implements the API

f$.$ Who invokes the AP