Module org.eclipse.persistence.jpa.jpql
Package org.eclipse.persistence.jpa.jpql.parser

Class EmptyCollectionComparisonExpression

java.lang.Object
org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.jpql.parser.EmptyCollectionComparisonExpression
All Implemented Interfaces:
Expression
public final class EmptyCollectionComparisonExpression extends AbstractExpression
This expression tests whether or not the collection designated by the collection-valued path expression is empty (i.e, has no elements).
BNF: empty_collection_comparison_expression ::= collection_valued_path_expression IS [NOT] EMPTY
Since:
2.3
Version:
2.5

  • Constructor Details

    • EmptyCollectionComparisonExpression

      public EmptyCollectionComparisonExpression(AbstractExpression parent, AbstractExpression expression)
      Creates a new NullComparisonExpression.
      Parameters:
      parent - The parent of this expression
      expression - The Expression that represents the collection-valued path expression

  • 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

    • getActualEmptyIdentifier

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

    • 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

    • getExpression

      public Expression getExpression()
      Returns the Expression that represents the collection-valued path expression if it was parsed.
      Returns:
      The expression that was parsed representing the collection valued path expression

    • getIdentifier

      public String getIdentifier()
      Returns the identifier for this expression that may include NOT if it was parsed. The identifier IS should always be part of the identifier but it is possible it is not present when this expression is invalid.
      Returns:
      Either IS NOT EMPTY, NOT EMPTY, IS EMPTY or EMPTY

    • 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 was parsed.
      Returns:
      true if the expression was parsed; false otherwise

    • hasNot

      public boolean hasNot()
      Determines whether the identifier NOT was part of the query.
      Returns:
      true if the identifier NOT was parsed; false otherwise

    • hasSpaceAfterIs

      public boolean hasSpaceAfterIs()
      Determines whether a whitespace was found after IS.
      Returns:
      true if there was a whitespace after IS; 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