Metro is a high-performance, extensible, easy-to-use web service stack. Although historically an open-source part of the GlassFish application server, it can also be used in a stand-alone configuration.[1] Components of Metro include: JAXB RI, JAX-WS RI, SAAJ RI, StAX (SJSXP implementation) and WSIT. Originally available under the CDDL and GPLv2 with classpath exception,[2] it is now available under Eclipse Distribution License [Wikidata]

Metro
Original author(s)Sun Microsystems
Developer(s)Eclipse Foundation
Initial releaseSeptember 17, 2007; 17 years ago (2007-09-17)
Stable release
3.0.1 / April 14, 2021; 3 years ago (2021-04-14)
Written inJava
PlatformJakarta EE
Typeweb service framework
LicenseEDL 1.0 [Wikidata]
Websiteprojects.eclipse.org/projects/ee4j.metro Edit this at Wikidata

History

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Originally, the Glassfish project developed two semi-independent projects:

  • JAX-WS RI, the Reference implementation of the JAX-WS specification
  • WSIT, a Java implementation of some of the WS-* and an enhanced support for interoperability with the .NET Framework. It is based on JAX-WS RI as "Web Service layer".

In June 2007, it was decided to bundle these two components as a single component named Metro.[3]

Features

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Metro compares well with other web service frameworks in terms of functionality. Codehaus started a comparison[4] which compared Apache Axis 1.x, Axis 2.x, Celtix, Glue, JBossWS, Xfire 1.2 and JAX-WS RI + WSIT (the bundle was not yet named Metro at that time). This was later updated by the ASF to replace Celtix with CXF and to include OracleAS 10g.[5]

Metro includes JAXB RI, JAX-WS RI, SAAJ RI, SJSXP, and WSIT, along with libraries that those components depend on, such as xmlstreambuffer, mimepull, etc.[6]

Its features include:

  • Basic Profile 1.1 Compliant
  • Easily Create Services from POJOs
  • RPC-Encoding
  • Spring Support
  • REST Support
  • Soap 1.1/1.2
  • Streaming XML (StAX based)
  • WSDL 1.1 ->Code (Client)/(Server)
  • Server and Client-side Asynchrony[5]

Supported WS-* Standards[5]

WS-Addressing WS-Atomic Transaction WS-Coordination
WS-Metadata Exchange WS-ReliableMessaging WS-Policy
WS-Secure Conversation WS-Security Policy WS-Security
WS-Trust WSDL 1.1 Support

Supported Transport protocols include:

  • HTTP
  • JMS
  • SMTP/POP3
  • TCP
  • In-VM

Metro augments the JAX-WS environment with advanced features such as trusted, end-to-end security; optimized transport (MTOM, Fast Infoset), reliable messaging, and transactional behavior for SOAP web services.

Market share

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Metro is bundled with Java SE 6 in order to allow consumers of Java SE 6 to consume Web Services.[7]

Metro is bundled with numerous application servers such as:[8]

The JAXB reference implementation developed for Metro is used in virtually every Java Web Services framework (Apache Axis2, Codehaus XFire, Apache CXF) and Application Servers.

References

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  1. ^ "metro: Discover Metro". Archived from the original on 2007-07-08.
  2. ^ "metro: Metro FAQ".
  3. ^ Gupta, Arun (June 19, 2007). "Announcing Metro - Naming the Web Services stack in GlassFish". Miles to go…. blogs.sun.com. Archived from the original on 2009-09-26.
  4. ^ "Stack Comparison". XFire. xfire.codehaus.org. Archived from the original on 2006-12-30.
  5. ^ a b c "StackComparison". Apache Web Services Wiki. Apache Wiki Farm. Archived from the original on 2017-09-04.
  6. ^ "Metro".
  7. ^ "JAX-WS FAQ". jax-ws. Archived from the original on 2007-08-07.
  8. ^ Gupta, Arun (July 22, 2007). "Metro - Now on Tomcat 6.x also". GlassFish. blogs.sun.com. Archived from the original on 2009-06-15.
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