Package org.apache.cassandra.cql3.selection

Class Selector.Factory

java.lang.Object
org.apache.cassandra.cql3.selection.Selector.Factory
Direct Known Subclasses:
SimpleSelector.SimpleSelectorFactory
Enclosing class:
Selector
public abstract static class Selector.Factory extends Object
A factory for Selector instances.

  • Constructor Details

    • Factory

      public Factory()

  • Method Details

    • addFunctionsTo

      public void addFunctionsTo(List<Function> functions)

    • getColumnSpecification

      public ColumnSpecification getColumnSpecification(TableMetadata table)
      Returns the column specification corresponding to the output value of the selector instances created by this factory.
      Parameters:
      table - the table meta data
      Returns:
      a column specification

    • newInstance

      public abstract Selector newInstance(QueryOptions options)
      Creates a new Selector instance.
      Parameters:
      options - the options of the query for which the instance is created (some selector depends on the bound values in particular).
      Returns:
      a new Selector instance

    • isAggregateSelectorFactory

      public boolean isAggregateSelectorFactory()
      Checks if this factory creates selectors instances that creates aggregates.
      Returns:
      true if this factory creates selectors instances that creates aggregates, false otherwise

    • isWritetimeSelectorFactory

      public boolean isWritetimeSelectorFactory()
      Checks if this factory creates writetime selectors instances.
      Returns:
      true if this factory creates writetime selectors instances, false otherwise

    • isMaxWritetimeSelectorFactory

      public boolean isMaxWritetimeSelectorFactory()
      Checks if this factory creates maxwritetime selector instances.
      Returns:
      true if this factory creates maxwritetime selectors instances, false otherwise

    • isTTLSelectorFactory

      public boolean isTTLSelectorFactory()
      Checks if this factory creates TTL selectors instances.
      Returns:
      true if this factory creates TTL selectors instances, false otherwise

    • isSimpleSelectorFactory

      public boolean isSimpleSelectorFactory()
      Checks if this factory creates Selectors that simply return a column value.
      Returns:
      true if this factory creates Selectors that simply return a column value, false otherwise.

    • isSimpleSelectorFactoryFor

      public boolean isSimpleSelectorFactoryFor(int index)
      Checks if this factory creates Selectors that simply return the specified column.
      Parameters:
      index - the column index
      Returns:
      true if this factory creates Selectors that simply return the specified column, false otherwise.

    • getColumnName

      protected abstract String getColumnName()
      Returns the name of the column corresponding to the output value of the selector instances created by this factory.
      Returns:
      a column name

    • getReturnType

      protected abstract AbstractType<?> getReturnType()
      Returns the type of the values returned by the selector instances created by this factory.
      Returns:
      the selector output type

    • addColumnMapping

      protected abstract void addColumnMapping(SelectionColumnMapping mapping, ColumnSpecification resultsColumn)
      Record a mapping between the ColumnDefinitions that are used by the selector instances created by this factory and a column in the ResultSet.Metadata returned with a query. In most cases, this is likely to be a 1:1 mapping, but some selector instances may utilise multiple columns (or none at all) to produce a value (i.e. functions).
      Parameters:
      mapping - the instance of the column mapping belonging to the current query's Selection
      resultsColumn - the column in the ResultSet.Metadata to which the ColumnDefinitions used by the Selector are to be mapped