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

public final class UnionClause extends AbstractExpression
The UNION clause allows the results of two queries to be combined.
BNF: union_clause ::= { UNION | INTERSECT | EXCEPT } [ALL] subquery
Since:
2.4
Version:
2.5
  • Constructor Details

    • UnionClause

      public UnionClause(AbstractExpression parent, String identifier)
      Creates a new UnionClause.
      Parameters:
      parent - The parent of this expression
      identifier - Either UNION, INTERSECT or EXCEPT
  • 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
    • getActualAll

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

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

      public String getIdentifier()
      Returns the union identifier.
      Returns:
      Either "UNION", "INTERSECT", "EXCEPT"
    • getQuery

      public Expression getQuery()
      Returns the Expression representing the unioned query.
      Returns:
      The Expression representing the subquery
    • 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
    • hasAll

      public boolean hasAll()
      Determines whether ALL was parsed.
      Returns:
      true if ALL was parsed; false otherwise
    • hasQuery

      public boolean hasQuery()
      Determines whether the query was parsed.
      Returns:
      true the query was parsed; false otherwise
    • hasSpaceAfterAll

      public boolean hasSpaceAfterAll()
      Determines whether a whitespace was parsed after ALL.
      Returns:
      true if a whitespace was parsed after ALL; false otherwise
    • hasSpaceAfterIdentifier

      public boolean hasSpaceAfterIdentifier()
      Determines whether a whitespace was parsed after the identifier.
      Returns:
      true if a whitespace was parsed after the identifier; false otherwise
    • isExcept

      public boolean isExcept()
      Determines whether this UnionClause uses the EXCEPT identifier.
      Returns:
      true if the identifier is EXCEPT; false otherwise
    • isIntersect

      public boolean isIntersect()
      Determines whether this UnionClause uses the INTERSECT identifier.
      Returns:
      true if the identifier is INTERSECT; false otherwise
    • isParsingComplete

      protected boolean isParsingComplete(WordParser wordParser, String word, Expression expression)
      Description copied from class: AbstractExpression
      Determines whether the parsing is complete based on what is left in the given text. The text is never empty.
      Overrides:
      isParsingComplete in class AbstractExpression
      Parameters:
      wordParser - The text to parse based on the current position of the cursor
      word - The word that was retrieved from the given text, which is the first word in the text
      expression - The Expression that has already been parsed
      Returns:
      true if the text no longer can't be parsed by the current expression; false if more can be parsed
    • isUnion

      public boolean isUnion()
      Determines whether this UnionClause uses the UNION identifier.
      Returns:
      true if the identifier is UNION; 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
    • parseIdentifier

      protected String parseIdentifier()
      Parses the JPQL identifier identifier the type of union.
      Returns:
      Either UNION, INTERSECT or EXCEPT
    • 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