Class NullValue

java.lang.Object
adql.query.operand.NullValue
All Implemented Interfaces:
ADQLObject, ADQLOperand

public class NullValue extends Object implements ADQLOperand
Special value representing the absence of value (i.e. NULL in SQL).
Since:
2.0
  • Field Details

  • Constructor Details

  • Method Details

    • getFeatureDescription

      public final LanguageFeature getFeatureDescription()
      Description copied from interface: ADQLObject
      Get the description of this ADQL's Language Feature.

      Note: Getting this description is generally only useful when discovery optional features so that determining if they are allowed to be used in ADQL queries.

      Specified by:
      getFeatureDescription in interface ADQLObject
      Returns:
      Description of this ADQL object as an ADQL's feature.
    • isNumeric

      public final boolean isNumeric()
      Always returns true.
      Specified by:
      isNumeric in interface ADQLOperand
      Returns:
      true if this operand is numeric, false otherwise.
      See Also:
    • isString

      public final boolean isString()
      Always returns true.
      Specified by:
      isString in interface ADQLOperand
      Returns:
      true if this operand is a string, false otherwise.
      See Also:
    • getPosition

      public final TextPosition getPosition()
      Description copied from interface: ADQLObject
      Gets the position of this object/token in the ADQL query.

      By default, no position should be set.

      Specified by:
      getPosition in interface ADQLObject
      Returns:
      Position of this ADQL item in the ADQL query, or NULL if not written originally in the query (for example, if added afterwards).
    • setPosition

      public final void setPosition(TextPosition position)
      Sets the position at which this NullValue has been found in the original ADQL query string.
      Parameters:
      position - Position of this NullValue.
    • isGeometry

      public final boolean isGeometry()
      Always returns true.
      Specified by:
      isGeometry in interface ADQLOperand
      Returns:
      true if this operand is a geometry, false otherwise.
      See Also:
    • getCopy

      public ADQLObject getCopy()
      Description copied from interface: ADQLObject
      Gets a (deep) copy of this ADQL object.
      Specified by:
      getCopy in interface ADQLObject
      Returns:
      The copy of this ADQL object.
    • getName

      public String getName()
      Description copied from interface: ADQLObject
      Gets the name of this object in ADQL.
      Specified by:
      getName in interface ADQLObject
      Returns:
      The name of this ADQL object.
    • adqlIterator

      public ADQLIterator adqlIterator()
      Description copied from interface: ADQLObject
      Gets an iterator on the intern ADQL objects.

      Note: The returned iterator is particularly used by a ISearchHandler extension to browse a whole ADQL tree.

      Specified by:
      adqlIterator in interface ADQLObject
      Returns:
      An ADQL objects iterator.
      See Also:
    • toADQL

      public String toADQL()
      Description copied from interface: ADQLObject
      Gets the ADQL expression of this object.
      Specified by:
      toADQL in interface ADQLObject
      Returns:
      The corresponding ADQL expression.