Class ProxyReader

Method Details

• map

  public static ProxyReader map(DataReader reader, Function<Record,Record> mapper) throws Throwable

  Wraps the reader in a proxy that passes each record through the mapper; a null result drops the record.

  Throws:

  Throwable

• map

  public static ProxyReader map(DataReader reader, BiFunction<ProxyReader,Record,Record> mapper) throws Throwable

  Wraps the reader in a proxy that passes itself and each record to the mapper; a null result drops the record.

  Throws:

  Throwable

• getNestedReader

  public DataReader getNestedReader()

  Description copied from class: DataReader

  Returns the DataReader held inside this one or null if there isn't one.

  Overrides:

  getNestedReader in class DataReader

• setNestedDataReader

  protected void setNestedDataReader(DataReader nestedDataReader)

  Make sure to close old target and open the new one or call with true.

• setNestedDataReader

  protected void setNestedDataReader(DataReader nestedDataReader, boolean manageLifecycle) throws DataException

  Replaces the nested reader; with manageLifecycle the old reader is closed and, if this proxy is open, the new one is opened.

  Throws:

  DataException

• available

  public int available() throws DataException

  Description copied from class: DataReader

  Returns the number of records that can probably be read without blocking.

  Overrides:

  available in class DataReader

  Throws:

  DataException

• open

  public void open() throws DataException

  Description copied from class: DataEndpoint

  Makes this endpoint ready for reading or writing.

  Overrides:

  open in class DataEndpoint

  Throws:

  DataException

• close

  public void close() throws DataException

  Description copied from class: DataEndpoint

  Indicates that this endpoint has finished reading or writing.

  Overrides:

  close in class DataEndpoint

  Throws:

  DataException

• interceptRecord

  protected Record interceptRecord(Record record) throws Throwable

  Overridden by subclasses to transform, drop, or observe a record on its way through this proxy.

  Contract for subclasses (see also docs/authoring/ProxyReader.md):

  • Return the record (possibly modified) to pass it downstream.
  • Return null to drop the record; the framework reads the next one.
  • Throw to fail the pipeline; the framework wraps the throwable in a DataException with .setRecord(record).
  • The nested DataReader is opened and closed for you; do not read from it here.
  • Do not call DataEndpoint.incrementRecordCount() here.

  Throws:

  Throwable

• readImpl

  protected Record readImpl() throws Throwable

  Description copied from class: DataReader

  Overridden by subclasses to read the next record from this DataReader. The default implementation of DataReader.read() now insures that this method will not be called again after it returns a null.

  If no record is available, null will be returned.

  Contract for subclasses (see also docs/authoring/DataReader.md):

  • Return null exactly once to signal end-of-stream.
  • Do not call this method directly — DataReader.read() is the template method that wraps exceptions, increments the record count, and tracks lineage.
  • Do not call DataEndpoint.incrementRecordCount() here; DataReader.read() already does.
  • Throw raw exceptions; DataReader.read() wraps them via exception(throwable).

  Specified by:

  readImpl in class DataReader

  Throws:

  Throwable

• addExceptionProperties

  public DataException addExceptionProperties(DataException exception)

  Description copied from class: Endpoint

  Adds this endpoint's current state to a DataException. Since this method is called whenever an exception is thrown, subclasses should override it to add their specific information.

  Overrides:

  addExceptionProperties in class DataReader