Joint METOC Broker Language (JMBL)

The Joint METOC Broker Language is a specification for a standard language that will broker the exchange of information between METOC data providers and user applications.

The Joint METOC Broker Language is: XML based Developed after Common Operating Environment (COE) segment schema Designed for Flexible use

Intro to Joint METOC Broker Language (JMBL)

What is JMBL?

JMBL is a specification for a standard language that will broker the exchange of information between meteorological and oceanographic (METOC) data providers and user applications. JMBL allows for a standardized interface to access METOC data for users and their applications. The way this information is exchanged is with a Web service.

What are Web Services?

On the surface, a Web service is simply an application that exposes a Web-accessible application programming interface (API). That means you can invoke this application programmatically over the Web. Applications invoking this Web service are referred to as clients. The client sends a request to the Web service and receives back a response from the Web service. The format of the request, response, and the communications are specified by the Web service. With JMBL the request and response are Extensible Markup Language (XML) messages embedded in SOAP messages that are exchanged between the client and service. SOAP is a standardized protocol for exchanging XML-based messages over a computer network, normally using HTTP.

Building your own JMBL Interface to the JMBL Web Service

Invoking the JMBL Web service refers to the actions that a client application performs to use the JMBL Web Service. Client applications that invoke Web Services can be written using any technology: Java, C++, Perl, Microsoft SOAP Toolkit, .NET, and so on. The JMBL Web Service allows the user the capabilities to create their own interface to the JMBL Web Service. The only requirement is that the SOAP front end must wrap the JMBL request and the JMBL request must be compliant to the JMBL XML schemas to gain access to the JMBL Web Service data. In order to lessen the amount of development needed to create a JMBL interface, the Air Force Weather Agency (AFWA) provides the Java JMBL Adaptor. The Java JMBL Adaptor can be used to request weather data from the METOC databases at AFWA. It supports the JMBL 3.x standard. The adaptor submits a user-defined XML-based request and by default returns a JMBL response which is saved as a comma-separated file containing the requested data. The user is able to configure both the request and the format of the response (style sheet) in order to obtain the required data in the necessary format. The Adaptor includes installers for Windows, AIX, and Solaris. The AdaptorÂ’s Java code is portable to other platforms also.

Communicating with the JMBL Web Service

SOAP defines a binding to the HTTP protocol. This binding describes the relationship between parts of the SOAP request message and various HTTP headers. All SOAP requests use the HTTP POST method and specify at least three HTTP headers: Content-Type, Content-Length and a custom header SOAPAction. The actual SOAP message is then passed as the body of the request. The SOAP request handler receives SOAP requests, (looks up the appropriate service implementation class, invokes the requested method, and returns a SOAP response).

Creating an Interface to JMBL

The user can create an interface that will take a user generated XML file and encapsulate it within the SOAP request to a JMBL Web service. The interface can be written in C, C++, Java or any high-level programming language that will accept an XML file and generate a SOAP request, and receive a SOAP response, to the JM Web service.

More information

For more information, including the JMBL Users Guide and Java JMBL Adaptor, please visit AFWA's JMBL webpage.

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