All resources are implemented in classes in the package We call all elements directly nested in the definitions element “components”. They are implemented using JAX RS using Jersey.

The full set the API is used by the Management user interface and the Topology Modeler.

URL Structure

The idea behind the URL structure may shortly describes by ROOT/<componenttype>s/<double-encoded-namespace>/<double-encoded-id>/<resource-specific-part>, which makes the structure similar to one of the file system. Encoding is done following RFC 3986. An online URL-encoder may be found at:

For instance, the NodeType “NT1” in the namespace is found at the URL nodetypes/ As the browser decodes the URL, the namespace and the id are double encoded. Note the additional encoding of the symbol % in comparison to the encoding at the filesystem. This is due to security decisions to disallow %2F in URLs.

The part until <componenttype>s is realized by “AbstractComponentsResource” and its subclasses. The resource specific part is realized by subclasses of AbstractComponentInstanceResource.

More information on encoding is given at Encoding.

Collections of Components


The figure above shows the inheritance of AbstractComponentsResource. It contains an intermediate class AbstractComponentsWithTypeReferenceResource which handles a POST with an additional type. It is used at all components which have a type associated. These are artifact templates, node type implementations, relationship type implementations and policy templates.

All logic is implemented in AbstractComponentsResource. It handles creation of resources (using POST) and creation of AbstractComponentInstanceResources.

Component Instances


The figure above shows the inheritance of AbstractComponentInstanceResource. For each component, a class exists. Using Intermediate classes, common properties are handled. These are explained in the following sections.


Several component instances have the attributes name, dervidedFrom, abstract, and final. These are handled in the class AbstractComponentInstanceResourceWithNameDerivedFromAbstractFinal. In this group, type implementations, namely node type implementations and relationship type implementations can be found.

Furthermore, type resources exist. These are grouped by the EntityTypeResource. Within the context of this class, TopologyGraphElementEntityTypeResource is introduced. This class groups together NodeTypeResource and RelationshipTypeResource.


This class groups together classes with file references. Artifact Templates may reference files and a Service Template may reference plans. The user can copy files manually to the right place in the directory structure of the repository. By calling the method synchronizeReferences(), the referenced stores in the XML are synchronized with the actually existing files. This is done whenever the XML is retrieved from the repository.


This class is used to handle different import types. Currently, only CSD is supported. The class is XSDImportResource.


This class implements the resource for a policy template. Since a policy template does not contain any external file references, it is not modeled as child of AbstractComponentInstanceWithReferencesResource.