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

Class AssertPredicate

java.lang.Object
com.pervasive.datarush.operators.AbstractLogicalOperator
com.pervasive.datarush.operators.StreamingOperator
com.pervasive.datarush.operators.ExecutableOperator
com.pervasive.datarush.operators.assertion.AssertPredicate
All Implemented Interfaces:
LogicalOperator
public class AssertPredicate extends ExecutableOperator
Assert that the given predicate is true for all input values. If the predicate is not true for any value an exception will be thrown halting execution. This is useful for comparing values within the same data flow.

  • Constructor Details

    • AssertPredicate

      public AssertPredicate()
      Create the assertion operator.

    • AssertPredicate

      public AssertPredicate(ScalarValuedFunction predicate)
      Create the assertion operator with the given predicate.
      Parameters:
      predicate - predicate function to assert

  • Method Details

    • getPredicate

      public ScalarValuedFunction getPredicate()
      Get the predicate function.
      Returns:
      predicate function

    • setPredicate

      public void setPredicate(ScalarValuedFunction predicate)
      Set the predicate function to assert. A predicate function must return a boolean type.
      Parameters:
      predicate - predicate function to assert
      Throws:
      com.pervasive.datarush.graphs.physical.InvalidPropertyValueException - thrown if the predicate function does not return a boolean type

    • setPredicate

      public void setPredicate(String predicateExpression)
      Sets the predicate(s) to use for assertion based on an expression similar to a where clause of a SQL query.
      Parameters:
      predicateExpression - predicate expression to apply

    • getInput

      public RecordPort getInput()
      Get the input port of this operator.
      Returns:
      input port

    • 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 context)
      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:
      context - context in which to lookup physical ports bound to logical ports