IDfCollections, Part V

In this final post of the IDfCollection series, I offer an alternative to the IDfCollection object, the dmRecordSet. The dmRecordSet is an object I created to extend the capabilities of the IDfCollection and overcome many of the limitations I have been discussing here. For example, the dmRecordSet allows you to:

• move forward, backward or randomly through the record set;
• reset the record set to the beginning or the end to be re-processed;
• add rows to the set;
• determine the number of rows in the set;
• determine if a record set is empty or not; and
• retrieve column definitions.

The following code provides some examples of how easy it is to use the dmRecordSet object.

Instantiate a dmRecordSet:

    IDfCollection col = null;
    String dql = "select r_object_id, object_name, "
           + "r_creation_date, a_content_type, r_full_content_size, a_is_template "
           + "from dm_document where folder('/Temp',descend)";
    IDfQuery q = new DfQuery();
    IDfTypedObject tObj = null;

    q.setDQL(dql);
    col = q.execute(session, DfQuery.DF_READ_QUERY);

    // get record set
    dmRecordSet dmRS = new dmRecordSet(col);

Test for empty set and count rows:

    System.out.println("Record count = " + dmRS.getRowCount());
    if (dmRS.isEmpty()) {
       System.out.println("dmRecordSet is empty");
    } else {
       System.out.println("dmRecordSet is NOT empty");
    }

Process record set:

    while (dmRS.hasNext()) {
       tObj = dmRS.next();
       System.out.print(tObj.getString("r_object_id") + "\t");
       System.out.println(tObj.getString("object_name");
    }

Move to end and process set backwards:

    tObj = dmRS.last();
    while (dmRS.hasPrevious()) {
        tObj = dmRS.previous();
        System.out.print(tObj.getString("r_object_id") + "\t");
        System.out.println(tObj.getString("object_name");
    }

The class, source code and Javadoc for the dmRecordSet can be downloaded here.

I hope you have enjoyed this series on the IDfCollection object, one of the most commonly used but least functional objects in the DFC.  As always, I appreciate your comments and feedback.

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