Package com.espertech.esper.common.client.hook.aggfunc

Class AggregationFunctionValidationContext

java.lang.Object
com.espertech.esper.common.client.hook.aggfunc.AggregationFunctionValidationContext
public class AggregationFunctionValidationContext extends Object
Context for use with plug-in custom aggregation functions that implement AggregationFunctionForge.

This context object provides access to the parameter expressions themselves as well as information compiled from the parameter expressions for your convenience.

  • Constructor Details

    • AggregationFunctionValidationContext

      public AggregationFunctionValidationContext(EPType[] parameterTypes, boolean[] constantValue, Object[] constantValues, boolean distinct, boolean windowed, ExprNode[] expressions, LinkedHashMap<String,List<ExprNode>> namedParameters)
      Ctor.
      Parameters:
      parameterTypes - the type of each parameter expression.
      constantValue - for each parameter expression an indicator whether the expression returns a constant result
      constantValues - for each parameter expression that returns a constant result this array contains the constant value
      distinct - true if 'distinct' keyword was provided
      windowed - true if all event properties references by parameter expressions are from streams that have data windows declared onto the stream or are from named windows
      expressions - the parameter expressions themselves (positional parameters only)
      namedParameters - provided when there are named parameters, such as the "filter:expression" parameter

  • Method Details

    • getParameterTypes

      public EPType[] getParameterTypes()
      The return type of each parameter expression.

      This information can also be obtained by calling getType on each parameter expression.

      Returns:
      array providing result type of each parameter expression

    • getIsConstantValue

      public boolean[] getIsConstantValue()
      A boolean indicator for each parameter expression that is true if the expression returns a constant result or false if the expression result is not a constant value.

      This information can also be obtained by calling isConstantResult on each parameter expression.

      Returns:
      array providing an indicator per parameter expression that the result is a constant value

    • getConstantValues

      public Object[] getConstantValues()
      If a parameter expression returns a constant value, the value of the constant it returns is provided in this array.

      This information can also be obtained by calling evaluate on each parameter expression providing a constant value.

      Returns:
      array providing the constant return value per parameter expression that has constant result value, or null if a parameter expression is deemded to not provide a constant result value

    • isDistinct

      public boolean isDistinct()
      Returns true to indicate that the 'distinct' keyword was specified for this aggregation function.
      Returns:
      distinct value indicator

    • isWindowed

      public boolean isWindowed()
      Returns true to indicate that all parameter expressions return event properties that originate from a stream that provides a remove stream.
      Returns:
      windowed indicator

    • getExpressions

      public ExprNode[] getExpressions()
      Returns the parameter expressions themselves for interrogation.
      Returns:
      parameter expressions

    • getNamedParameters

      public LinkedHashMap<String,List<ExprNode>> getNamedParameters()
      Returns any named parameters or null if there are no named parameters
      Returns:
      named parameters