Database Reference
In-Depth Information
• Runtime message validation
• XPath-oriented
• No post compilation required for code injection
• Can support very complex message structures
The JAXB API is part of Java SE and EE package bundles, but still it is better to check
for the latest release if performance is an issue. If serialization performance is the major
concern, look at the JiBX more closely as it could be up to five times (some claim more)
faster.
Here again, the reliability and predictability of parser should be balanced with reasonable
performance; otherwise, you will have to rebuild your services from scratch every time
the XSD specifications change.
So, in the JWS specification, JAXB is responsible for mapping a Java class to the mes-
sage's XSD using customizable annotations.
Java API for XML Web Services
(
JAX-
WS
) is the technology that is responsible for mapping Java parameters to the WSDL de-
claration. These two specifications conclude
service endpoint interface
(
SEI
) as the rep-
resentation of a standardized contract. Of course, just using them alone doesn't guarantee
that contract will be truly standardized, but they are the two essential technical WS specs.
The last and the most important part of the
WS
spec is the web container; it is responsible
for performing basic HTTP operations:
POST
and
GET
. It's related to the handling of
transport protocols, and we will discuss it right away.
WS transports
XML-based SOAP-messaging protocol handled by the web container is typically imple-
mented as a servlet if you need to utilize the HTTP transport protocol, which is most com-
mon for JWS. SOAP is a type of XML structure, serving as a container for service mes-
sage interactions. There are two mandatory parts:
soap:Envelope
as a root and
soap:Body
that acts as a business payload container. Two optional elements can also be
present:
soap:Header
and
soap:Fault
. Although the header element is optional, its
role for providing transport and processing-related metadata is enormous. Most of the
WS-*
extensions followed after the first publication of initial WS specs are related to the
SOAP headers. There are some which could be equally distributed between the header
and body. For instance,
WS-Security
naturally relates to the body and header via en-
crypted and signed elements and
WS-MetadataExchange
provides and distributes
WSDL-related data necessary for establishing service interactions, which can also be done
via the SOAP body.
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