Adding metadata to Java UDx libraries

To add metadata to your Java UDx library, you create a subclass of the UDXLibrary class that contains your library's metadata.

You can add metadata, such as author name, the version of the library, a description of your library, and so on to your library. This metadata lets you track the version of your function that is deployed on a Vertica Analytic Database cluster and lets third-party users of your function know who created the function. Your library's metadata appears in the USER_LIBRARIES system table after your library has been loaded into the Vertica Analytic Database catalog.

To add metadata to your Java UDx library, you create a subclass of the UDXLibrary class that contains your library's metadata. You then include this class within your JAR file. When you load your class into the Vertica Analytic Database catalog using the CREATE LIBRARY statement, looks for a subclass of UDXLibrary for the library's metadata.

In your subclass of UDXLibrary, you need to implement eight getters that return String values containing the library's metadata. The getters in this class are:

getAuthor() returns the name you want associated with the creation of the library (your own name or your company's name for example).
getLibraryBuildTag() returns whatever String you want to use to represent the specific build of the library (for example, the SVN revision number or a timestamp of when the library was compiled). This is useful for tracking instances of your library as you are developing them.
getLibraryVersion() returns the version of your library. You can use whatever numbering or naming scheme you want.
getLibrarySDKVersion() returns the version of the Vertica Analytic Database SDK Library for which you've compiled the library.

Note
This field isn't used to determine whether a library is compatible with a version of the Vertica Analytic Database server. The version of the Vertica Analytic Database SDK you use to compile your library is embedded in the library when you compile it. It is this information that Vertica Analytic Database server uses to determine if your library is compatible with it.
getSourceUrl() returns a URL where users of your function can find more information about it. This can be your company's website, the GitHub page hosting your library's source code, or whatever site you like.
getDescription() returns a concise description of your library.
getLicensesRequired() returns a placeholder for licensing information. You must pass an empty string for this value.
getSignature() returns a placeholder for a signature that will authenticate your library. You must pass an empty string for this value.

For example, the following code demonstrates creating a UDXLibrary subclass to be included in the Add2Ints UDSF example JAR file (see /opt/vertica/sdk/examples/JavaUDx/ScalarFunctions on any Vertica node).

// Import the UDXLibrary class to hold the metadata
import com.vertica.sdk.UDXLibrary;

public class Add2IntsLibrary extends UDXLibrary
{
    // Return values for the metadata about this library.

    @Override public String getAuthor() {return "Whizzo Analytics Ltd.";}
    @Override public String getLibraryBuildTag() {return "1234";}
    @Override public String getLibraryVersion() {return "1.0";}
    @Override public String getLibrarySDKVersion() {return "7.0.0";}
    @Override public String getSourceUrl() {
        return "http://example.com/add2ints";
    }
    @Override public String getDescription() {
        return "My Awesome Add 2 Ints Library";
    }
    @Override public String getLicensesRequired() {return "";}
    @Override public String getSignature() {return "";}
}

When the library containing the Add2IntsLibrary class loaded, the metadata appears in the USER_LIBRARIES system table:

=> CREATE LIBRARY JavaAdd2IntsLib AS :libfile LANGUAGE 'JAVA';
CREATE LIBRARY
=> CREATE FUNCTION JavaAdd2Ints as LANGUAGE 'JAVA'  name 'com.mycompany.example.Add2IntsFactory' library JavaAdd2IntsLib;
CREATE FUNCTION
=> \x
Expanded display is on.
=> SELECT * FROM USER_LIBRARIES WHERE lib_name = 'JavaAdd2IntsLib';
-[ RECORD 1 ]-----+---------------------------------------------
schema_name       | public
lib_name          | JavaAdd2IntsLib
lib_oid           | 45035996273869844
author            | Whizzo Analytics Ltd.
owner_id          | 45035996273704962
lib_file_name     | public_JavaAdd2IntsLib_45035996273869844.jar
md5_sum           | f3bfc76791daee95e4e2c0f8a8d2737f
sdk_version       | v7.0.0-20131105
revision          | 125200
lib_build_tag     | 1234
lib_version       | 1.0
lib_sdk_version   | 7.0.0
source_url        | http://example.com/add2ints
description       | My Awesome Add 2 Ints Library
licenses_required |
signature         |