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

Class GroupByClause

java.lang.Object
org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.jpql.parser.GroupByClause
All Implemented Interfaces:
Expression
public final class GroupByClause extends AbstractExpression
The GROUP BY construct enables the aggregation of values according to the properties of an entity class.
BNF: groupby_clause ::= GROUP BY groupby_item {, groupby_item}*
Since:
2.3
Version:
2.5.1

  • Constructor Details

    • GroupByClause

      public GroupByClause(AbstractExpression parent)
      Creates a new GroupByClause.
      Parameters:
      parent - The parent of this 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

    • buildCollectionExpression

      public CollectionExpression buildCollectionExpression()
      Creates a new CollectionExpression that will wrap the single group by item.
      Returns:
      The single group by item represented by a temporary collection

    • 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

    • getActualIdentifier

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

    • getGroupByItems

      public Expression getGroupByItems()
      Returns the Expression that represents the list of group by items if any was parsed.
      Returns:
      The expression that was parsed representing the list of items

    • 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

    • hasGroupByItems

      public boolean hasGroupByItems()
      Determines whether the list of items was parsed.
      Returns:
      true if at least one item was parsed; false otherwise

    • hasSpaceAfterGroupBy

      public boolean hasSpaceAfterGroupBy()
      Determines whether a whitespace was found after GROUP BY.
      Returns:
      true if there was a whitespace after GROUP BY; 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