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Writing Open Metadata Archive Store Connectors

The open archive store connector manages the storage of an Open Metadata Archive. It is use in a utility or archive service that is maintaining an open metadata archive, and it is called in an Metadata Access Store when it is loading metadata from the archive.

Open Metadata Archive Store Connector

Interface and Base Classes

The definition of the open metadata archive connector interface is defined in the repository-services-api module in the org.odpi.openmetadata.repositoryservices.connectors.stores.archivestore Java package.

Its interface is called OpenMetadataArchiveStore 

public interface OpenMetadataArchiveStore
{
    /**
     * Return the contents of the archive.
     *
     * @return OpenMetadataArchive object
     */
    OpenMetadataArchive getArchiveContents();


    /**
     * Set new contents into the archive.  This overrides any content previously stored.
     *
     * @param archiveContents  OpenMetadataArchive object
     */
    void setArchiveContents(OpenMetadataArchive archiveContents);
}

The open metadata archive structure is defined by OpenMetadataArchive :material-github.

There are 3 sections:

Section Description
archiveProperties provides details of the source and contents of the archive
archiveTypeStore a list of new AttributeTypeDefs, new TypeDefs and patches to existing TypeDefs
archiveInstanceStore a list of new metadata instances (Entities, Relationships and Classifications)

The definition of the connector interface for these connectors is defined in the repository-services-api module in the org.odpi.openmetadata.repositoryservices.connectors.stores.archivestore Java package.

Example Implementations

Implementations of this type of connector is located in the adapters/open-connectors/repository-services-connectors/open-metadata-archive-connectors module.

Build Dependencies

<dependencies>

    <dependency>
        <groupId>org.odpi.egeria</groupId>
        <artifactId>open-connector-framework</artifactId>
    </dependency>

     <dependency>
        <groupId>org.odpi.egeria</groupId>
        <artifactId>repository-services-apis</artifactId>
     </dependency>

</dependencies>

dependencies {
    implementation project(':open-metadata-implementation:frameworks:open-connector-framework')
    implementation project(':open-metadata-implementation:repository-services:repository-services-apis')
}

Writing the Connector Provider

Each connector provider implements the following interface:

org.odpi.openmetadata.frameworks.connectors.ConnectorProvider

There is a base class that provides much of the implementation for a connector provider.

org.odpi.openmetadata.frameworks.connectors.ConnectorProviderBase

This assumes:

  • There is a single connector implementation class for the connector.
  • The connector is instantiated with the default constructor. This means all of its configuration information is contained in the Connection object supplied on the initialize() method.

If your connector implementation matches these requirements, its connector provider implementation need only implement a constructor to configure the base class's function with details of itself and the Java class of the connector it needs using:

  • a GUID for the connector type
  • a name for the connector type.
  • a description of what the connector is for and how to configure it.
  • the connector class it instantiates.
  • a list of the additional properties, configuration properties and secured properties needed to configure instances of the connector.
  • a description of the connector for its audit log (if the connector implements AuditLoggingComponent).
/**
 * XXXStoreProvider is the OCF connector provider for the XXX connector.
 */
public class XXXStoreProvider extends ConnectorProviderBase
{
    /*
     * Unique identifier of the connector for the audit log.
     */
    private static final int    connectorComponentId   = 10001; /* Add unique number here */

    /*
     * Unique identifier for the connector type.
     */
    private static final String connectorTypeGUID      = "Add unique GUID here";

    /*
     * Descriptive information about the connector for the connector type and audit log.
     */
    private static final String connectorQualifiedName = "MyOrg:XXXStoreConnector";
    private static final String connectorDisplayName   = "XXX Store Connector";
    private static final String connectorDescription   = "Connector supports ... add details here.";
    private static final String connectorWikiPage      = "Add url to documentation here";


    /*
     * Define the name of the connector implementation.
     */
    private static final String connectorClassName = "packagename.XXXStoreConnector";

    /*
     * Define the name of configuration properties.
     */
    public static final String TEMPLATE_QUALIFIED_NAME_CONFIGURATION_PROPERTY = "templateQualifiedName";

    /**
     * Constructor used to initialize the ConnectorProviderBase class.
     */
    public XXXStoreProvider()
    {
        super();

        /*
         * Set up the class name of the connector that this provider creates.
         */
        super.setConnectorClassName(connectorClassName);

        /*
         * Set up the connector type that should be included in a connection used to configure this connector.
         */
        ConnectorType connectorType = new ConnectorType();
        connectorType.setType(ConnectorType.getConnectorTypeType());
        connectorType.setGUID(connectorTypeGUID);
        connectorType.setQualifiedName(connectorQualifiedName);
        connectorType.setDisplayName(connectorDisplayName);
        connectorType.setDescription(connectorDescription);
        connectorType.setConnectorProviderClassName(this.getClass().getName());

        List<String> recognizedConfigurationProperties = new ArrayList<>();
        recognizedConfigurationProperties.add(TEMPLATE_QUALIFIED_NAME_CONFIGURATION_PROPERTY);
        connectorType.setRecognizedConfigurationProperties(recognizedConfigurationProperties);

        super.connectorTypeBean = connectorType;

        /*
         * Set up the component description used in the connector's audit log messages.
         */
        AuditLogReportingComponent componentDescription = new AuditLogReportingComponent();

        componentDescription.setComponentId(connectorComponentId);
        componentDescription.setComponentName(connectorQualifiedName);
        componentDescription.setComponentDescription(connectorDescription);
        componentDescription.setComponentWikiURL(connectorWikiPage);

        super.setConnectorComponentDescription(componentDescription);
    }
}

Writing the Connector

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