Class NullComparisonExpression

java.lang.Object
org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.jpql.parser.NullComparisonExpression
All Implemented Interfaces:
Expression

public final class NullComparisonExpression extends AbstractExpression
A null comparison tests whether or not the single-valued path expression or input parameter is a NULL value.
BNF: null_comparison_expression ::= {single_valued_path_expression | input_parameter} IS [NOT] NULL
Since:
2.3
Version:
2.5
  • Constructor Details

    • NullComparisonExpression

      public NullComparisonExpression(AbstractExpression parent, String identifier, AbstractExpression expression)
      Creates a new NullComparisonExpression.
      Parameters:
      parent - The parent of this expression
      expression - The expression before the identifier
  • Method Details

    • accept

      public void accept(ExpressionVisitor visitor)
      Description copied from interface: Expression
      Visits this Expression by the given visitor.
      Parameters:
      visitor - The ExpressionVisitor to visit this object
    • acceptChildren

      public void acceptChildren(ExpressionVisitor visitor)
      Description copied from interface: Expression
      Visits the children of this Expression. This method can be used to optimize traversing the children since a new list is not created every time Expression.children() is called.

      This does not traverse the Expression sub-hierarchy, use a subclass of AbstractTraverseChildrenVisitor in order to traverse the entire sub-hierarchy.

      Parameters:
      visitor - The visitor to visit the children of this object.
    • addChildrenTo

      protected void addChildrenTo(Collection<Expression> children)
      Description copied from class: AbstractExpression
      Adds the children of this AbstractExpression to the given collection.
      Overrides:
      addChildrenTo in class AbstractExpression
      Parameters:
      children - The collection used to store the children
    • addOrderedChildrenTo

      protected void addOrderedChildrenTo(List<Expression> children)
      Description copied from class: AbstractExpression
      Adds the children of this AbstractExpression to the given list.
      Overrides:
      addOrderedChildrenTo in class AbstractExpression
      Parameters:
      children - The list used to store the string representation of this AbstractExpression
    • findQueryBNF

      public JPQLQueryBNF findQueryBNF(Expression expression)
      Description copied from interface: Expression
      Retrieves the JPQLQueryBNF that represents the fragment of this Expression that was used when parsing the given Expression.
      Specified by:
      findQueryBNF in interface Expression
      Overrides:
      findQueryBNF in class AbstractExpression
      Parameters:
      expression - The Expression that is a descendant of this one
      Returns:
      The JPQLQueryBNF that was used to parse the given expression
    • getActualIsIdentifier

      public String getActualIsIdentifier()
      Returns the actual IS found in the string representation of the JPQL query, which has the actual case that was used.
      Returns:
      The IS identifier that was actually parsed, or an empty string if it was not parsed
    • getActualNotIdentifier

      public String getActualNotIdentifier()
      Returns the actual Not found in the string representation of the JPQL query, which has the actual case that was used.
      Returns:
      The NOT identifier that was actually parsed, or an empty string if it was not parsed
    • getActualNullIdentifier

      public String getActualNullIdentifier()
      Returns the actual NULL found in the string representation of the JPQL query, which has the actual case that was used.
      Returns:
      The NULL identifier that was actually parsed
    • getExpression

      public Expression getExpression()
      Returns the expression being tested for being null.
      Returns:
      Either the parsed expression or the null-expression
    • getIdentifier

      public String getIdentifier()
      Returns the identifier for this expression that may include NOT if it was parsed.
      Returns:
      Either IS NULL or IS NOT NULL
    • getQueryBNF

      public JPQLQueryBNF getQueryBNF()
      Description copied from interface: Expression
      Returns the BNF of this Expression.
      Returns:
      The JPQLQueryBNF, which represents the grammar of this Expression
    • hasExpression

      public boolean hasExpression()
      Determines whether the expression preceding the identifier was parsed.
      Returns:
      true the expression preceding the identifier was parsed; false otherwise
    • hasNot

      public boolean hasNot()
      Determines whether NOT is used in the query.
      Returns:
      true if NOT is present in the query; false otherwise
    • parse

      protected void parse(WordParser wordParser, boolean tolerant)
      Description copied from class: AbstractExpression
      Parses the query by starting at the current position, which is part of the given WordParser.
      Specified by:
      parse in class AbstractExpression
      Parameters:
      wordParser - The text to parse based on the current position of the cursor
      tolerant - Determines whether the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries
    • toParsedText

      protected void toParsedText(StringBuilder writer, boolean actual)
      Description copied from class: AbstractExpression
      Generates a string representation of this Expression, including its children, if it has any.
      Specified by:
      toParsedText in class AbstractExpression
      Parameters:
      writer - The buffer used to append this Expression's string representation
      actual - Determines whether the string representation should represent what was parsed, i.e. include any "virtual" whitespace (such as ending whitespace) and the actual case of the JPQL identifiers