Module datarush.library
Package com.pervasive.datarush.operators.sink

Class LogRows

  • All Implemented Interfaces:
    LogicalOperator, RecordSinkOperator, SinkOperator<RecordPort>
    public final class LogRows
extends ExecutableOperator
implements RecordSinkOperator
    Log information about the input data from a flow. The record type of the flow is logged. A log frequency is used to determine which data rows are logged. A data row is logged by outputing the value of each input field within the row. A format can be provided that specifies output format for each row log.

    • Constructor Detail

      • LogRows

        public LogRows()
        Default constructor. Uses default log frequency and row format.

      • LogRows

        public LogRows​(int frequency)
        Use the given log frequency and the default row format.
        Parameters:
        frequency - log frequency

      • LogRows

        public LogRows​(int frequency,
               String format)
        Use the given log frequency and row format.
        Parameters:
        frequency - log frequency
        format - row format

    • Method Detail

      • setLogFrequency

        public void setLogFrequency​(int logFrequency)
        Set the frequency of rows to log. Setting the frequency to 1 logs every row, a value of 2 logs every other row and so on. The default frequency of 0 turns off row logging.
        Parameters:
        logFrequency - log frequency (default 0)

      • getLogFrequency

        public int getLogFrequency()
        Get the configured log frequency.
        Returns:
        log frequency

      • setFormat

        public void setFormat​(String format)
        Set the format to use when logging rows. Reference MessageFormat for more information on the syntax of formats. Two variables are passed to the format: the row count and the row contents. The default format is "row {0} is {1}".
        Parameters:
        format - row format

      • getFormat

        public String getFormat()
        Get the configured row format.
        Returns:
        row format

      • computeMetadata

        protected void computeMetadata​(StreamingMetadataContext ctx)
        Description copied from class: StreamingOperator
        Implementations must adhere to the following contracts

        General

        Regardless of input ports/output port types, all implementations must do the following:

        1. Validation. Validation of configuration should always be performed first.
        2. Declare parallelizability.. Implementations must declare parallelizability by calling StreamingMetadataContext.parallelize(ParallelismStrategy).

        Input record ports

        Implementations with input record ports must declare the following:
        1. Required data ordering:
          2. Implementations that have data ordering requirements must declare them by calling RecordPort#setRequiredDataOrdering, otherwise data may arrive in any order.
        2. Required data distribution (only applies to parallelizable operators):
          3. Implementations that have data distribution requirements must declare them by calling RecordPort#setRequiredDataDistribution, otherwise data will arrive in an unspecified partial distribution.
        Note that if the upstream operator's output distribution/ordering is compatible with those required, we avoid a re-sort/re-distribution which is generally a very large savings from a performance standpoint. In addition, some operators may chose to query the upstream output distribution/ordering by calling RecordPort#getSourceDataDistribution and RecordPort#getSourceDataOrdering. These should be viewed as a hints to help chose a more efficient algorithm. In such cases, though, operators must still declare data ordering and data distribution requirements; otherwise there is no guarantee that data will arrive sorted/distributed as required.

        Output record ports

        Implementations with output record ports must declare the following:
        1. Type: Implementations must declare their output type by calling RecordPort#setType.
        Implementations with output record ports may declare the following:
        1. Output data ordering: Implementations that can make guarantees as to their output ordering may do so by calling RecordPort#setOutputDataOrdering
        2. Output data distribution (only applies to parallelizable operators): Implementations that can make guarantees as to their output distribution may do so by calling RecordPort#setOutputDataDistribution
        Note that both of these properties are optional; if unspecified, performance may suffer since the framework may unnecessarily re-sort/re-distributed the data.

        Input model ports

        In general, there is nothing special to declare for input model ports. Models are implicitly duplicated to all partitions when going from non-parallel to parallel operators. The case of a model going from a parallel to a non-parallel node is a special case of a "model reducer" operator. In the case of a model reducer, the downstream operator, must declare the following:
        1. Merge handler: Model reducers must declare a merge handler by calling AbstractModelPort#setMergeHandler.
        Note that MergeModel is a convenient, re-usable model reducer, parameterized with a merge-handler.

        Output model ports

        SimpleModelPort's have no associated metadata and therefore there is never any output metadata to declare. PMMLPort's, on the other hand, do have associated metadata. For all PMMLPorts, implementations must declare the following:
        1. pmmlModelSpec: Implementations must declare the PMML model spec by calling PMMLPort.setPMMLModelSpec.
        Specified by:
        computeMetadata in class StreamingOperator
        Parameters:
        ctx - the context

      • execute

        protected void execute​(ExecutionContext ctx)
        Description copied from class: ExecutableOperator
        Executes the operator. Implementations should adhere to the following contracts:
        1. Following execution, all input ports must be at end-of-data.
        2. Following execution, all output ports must be at end-of-data.
        Specified by:
        execute in class ExecutableOperator
        Parameters:
        ctx - context in which to lookup physical ports bound to logical ports