Class DDF

core/src/main/java/io/ddf/DDF.java:68–1178

A Distributed DataFrame (DDF) has a number of key properties (metadata, representations, etc.) and capabilities (self-compute basic statistics, aggregations, etc.). This class was designed using the Bridge Pattern to provide clean separation between the abstract concepts and the impleme

 * </p>
 */
public abstract class DDF extends ALoggable //
        implements IGloballyAddressable, IPersistible, ISupportPhantomReference, ISerializable {

  private static final long serialVersionUID = -2198317495102277825L;

  private Date mCreatedTime;

  //  Whether the ddf acts as a view for the database table.
  private boolean mIsDDFView = false;

  public boolean getIsDDFView() {
    return mIsDDFView;
  }

  public void setIsDDFView(boolean isDDFView) {
    this.mIsDDFView = isDDFView;
  }

  /**
   *
   * @param data
   *          The DDF data
   * @param namespace
   *          The namespace to place this DDF in. If null, it will be picked up from the DDFManager's current namespace.
   * @param name
   *          The name for this DDF. If null, it will come from the given schema. If that's null, a UUID-based name will
   *          be generated.
   * @param schema
   *          The {@link Schema} of the new DDF
   * @throws DDFException
   */
  public DDF(DDFManager manager, Object data, Class<?>[] typeSpecs,
             String namespace, String name, Schema schema)
          throws DDFException {

    this.initialize(manager, data, typeSpecs, namespace, name,
            schema);
  }

  abstract public DDF copy() throws DDFException;

  protected DDF(DDFManager manager, DDFManager defaultManagerIfNull) throws DDFException {
    this(manager != null ? manager : defaultManagerIfNull, null, null,
            null, null, null);
  }

  /**
   * This is intended primarily to provide a dummy DDF only. This signature must be provided by each implementor.
   *
   * @param manager
   * @throws DDFException
   */
  protected DDF(DDFManager manager) throws DDFException {
    this(manager, sDummyManager);
  }

  /**
   * cache for data computed from the DDF, e.g., ML models, DDF summary