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New metacard type definitions can be added to the running system by dropping them in to metadata folder (default is <DDF_HOME>/etc/metadata). Once a file is detected in that directory, the system will read it, parse it, and register the corresponding metacard type with the Metacard Type Registry. Once registered, the new metacard type can be used to generate new metacards of that type, or it can be used as the basis for new metacard type definitions.
Decision
Added a way to create metacard type definitions that can be injected but the design changed based on initial prototyping and use cases.
https://github.com/codice/ddf/tree/2.27.x/catalog/core/catalog-core-definitionparser
https://github.com/codice/ddf/tree/2.27.x/catalog/core/catalog-core-injectattribute