Java Reference
In-Depth Information
1.2 Web Service architecture
A service can be one of the three types of interaction: man-to-man, man-to-machine, or
machine-to- machine. A restaurant service is an example of man-to-man interaction. A
person withdrawing money from an Automated Teller Machine (ATM) is an example of
man-to-machine interaction. Machine-to- machine interaction is exemplified by a handheld
device, such as a smart device (e.g., a phone or a tablet), synchronizing its address book with
Microsoft Outlook. A Web Service is a type of machine-to-machine interaction that uses
specific Web standards and technology. A Web Service is a set of programming interfaces,
not a set of webpages.
This section begins with a basic definition of a Web Service in order to establish a basic
understanding for use in later chapters. More complex aspects of Web Services will be easi-
er to understand when the basic concept of a Web Service is properly explained.
According to W3C website,
http://www.w3.org/TR/ws-desc-reqs
:
A Web Service is a software application identified by a URI whose interfaces and
binding are capable of being defined, described and discovered by XML artifacts
and [that] supports direct interactions with other software applications using XML
based messages via Internet-based protocols.
A Web Service must involve a Web-based protocol, such as HTTP or Simple Mail Transfer
Protocol (SMTP). Other transport protocols may be used, but HTTP is the most common
one being used. HTTPS uses Secure Socket Layer (SSL) or Transport Secure Layer (TLS)
for secured transport of data. In regard to software development concerns, the difference
between HTTP and HTTPS is trivial. HTTP, thus, is used throughout this text.
A Web Service is a software application that requires interaction with another application.
WS is a software integration technique for a B2B type of integration. Here, one application
acts as a service provider (server) and the others act as service consumers (clients). This is a
many-to-one relationship.
'Interface' is defined as “[The] point of interaction or communication between a computer and
any other entity” (
http://www.thefreedictionary.com
)
. An interface can also be described
