Java Metadata Interface
Encyclopedia
Given that metadata is a set of descriptive, structural and administrative data
about a group of computer
data (for example such as a database schema
), Java Metadata Interface (or JMI) is a platform-neutral specification that defines the creation, storage, access, lookup and exchange of metadata in the Java programming language
.
and is defined by JSR 40 (a JSR is the formal document that describe proposed specifications and technologies for adding to the Java platform).
JMI is based on the Meta-Object Facility
(or MOF) specification from the Object Management Group
(or OMG). The MOF is a metamodel (a model of any kind of metadata) used notably to define the Unified Modeling Language
(or UML).
It supports the exchange of metadata through XMI. XMI is a standard for exchanging metadata information via Extensible Markup Language
(or XML). The MOF/XMI specifications are used for the exchange of UML models.
. There are many implementations of JMI, including the Reference Implementation from Unisys
, SAP NetWeaver and Sun Microsystems
's open-source implementation from the NetBeans
group. JMI is compatible with Java SE 1.3 and above through:
Data
The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...
about a group of computer
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
data (for example such as a database schema
Database schema
A database schema of a database system is its structure described in a formal language supported by the database management system and refers to the organization of data to create a blueprint of how a database will be constructed...
), Java Metadata Interface (or JMI) is a platform-neutral specification that defines the creation, storage, access, lookup and exchange of metadata in the Java programming language
Java (programming language)
Java is a programming language originally developed by James Gosling at Sun Microsystems and released in 1995 as a core component of Sun Microsystems' Java platform. The language derives much of its syntax from C and C++ but has a simpler object model and fewer low-level facilities...
.
History
The JMI specification was developed under the Java Community ProcessJava Community Process
The Java Community Process or JCP, established in 1998, is a formalized process that allows interested parties to get involved in the definition of future versions and features of the Java platform....
and is defined by JSR 40 (a JSR is the formal document that describe proposed specifications and technologies for adding to the Java platform).
JMI is based on the Meta-Object Facility
Meta-Object Facility
The Meta-Object Facility is an Object Management Group standard for model-driven engineering. The official reference page may be found at OMG's website.- Overview :...
(or MOF) specification from the Object Management Group
Object Management Group
Object Management Group is a consortium, originally aimed at setting standards for distributed object-oriented systems, and is now focused on modeling and model-based standards.- Overview :...
(or OMG). The MOF is a metamodel (a model of any kind of metadata) used notably to define the Unified Modeling Language
Unified Modeling Language
Unified Modeling Language is a standardized general-purpose modeling language in the field of object-oriented software engineering. The standard is managed, and was created, by the Object Management Group...
(or UML).
It supports the exchange of metadata through XMI. XMI is a standard for exchanging metadata information via Extensible Markup Language
Extensible Markup Language
Extensible Markup Language is a set of rules for encoding documents in machine-readable form. It is defined in the XML 1.0 Specification produced by the W3C, and several other related specifications, all gratis open standards....
(or XML). The MOF/XMI specifications are used for the exchange of UML models.
Usage
Essentially, JMI can be used to write tools in Java for manipulating UML models, which can be used in Model Driven Architecture and/or Model Driven DevelopmentModel-driven engineering
Model-driven engineering is a software development methodology which focuses on creating and exploiting domain models , rather than on the computing concepts...
. There are many implementations of JMI, including the Reference Implementation from Unisys
Unisys
Unisys Corporation , headquartered in Blue Bell, Pennsylvania, United States, and incorporated in Delaware, is a long established business whose core products now involves computing and networking.-History:...
, SAP NetWeaver and Sun Microsystems
Sun Microsystems
Sun Microsystems, Inc. was a company that sold :computers, computer components, :computer software, and :information technology services. Sun was founded on February 24, 1982...
's open-source implementation from the NetBeans
NetBeans
NetBeans refers to both a platform framework for Java desktop applications, and an integrated development environment for developing with Java, JavaScript, PHP, Python, Groovy, C, C++, Scala, Clojure, and others...
group. JMI is compatible with Java SE 1.3 and above through:
- Standardized mappings from the MOF modeling constructs to Java;
- Reflective APIs for generic discovery and navigation of metadata models and instances.