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

Class HierarchicalQueryClause

java.lang.Object
org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.jpql.parser.HierarchicalQueryClause
All Implemented Interfaces:
Expression
public final class HierarchicalQueryClause extends AbstractExpression
If a table contains hierarchical data, then rows can be selected in a hierarchical order using the hierarchical query clause.

START WITH specifies the root row(s) of the hierarchy.

CONNECT BY specifies the relationship between parent rows and child rows of the hierarchy.

BNF: hierarchical_query_clause ::= [start_with_clause] connectby_clause [order_siblings_by_clause]

Version:
2.5
See Also:
Author:
Pascal Filion

  • Constructor Details

    • HierarchicalQueryClause

      public HierarchicalQueryClause(AbstractExpression parent)
      Creates a new HierarchicalQueryClause.
      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

    • 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

    • getConnectByClause

      public Expression getConnectByClause()
      Returns the Expression representing the CONNECT BY clause.
      Returns:
      The expression representing the CONNECT BY clause

    • getOrderSiblingsByClause

      public Expression getOrderSiblingsByClause()
      Returns the Expression representing the ORDER SIBLINGS BY clause.
      Returns:
      The expression representing the ORDER SIBLINGS BY clause

    • 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

    • getStartWithClause

      public Expression getStartWithClause()
      Returns the Expression representing the START WITH clause.
      Returns:
      The expression representing the START WITH clause

    • hasConnectByClause

      public boolean hasConnectByClause()
      Determines whether the CONNECT BY clause is defined.
      Returns:
      true if the query that got parsed had the CONNECT BY clause

    • hasOrderSiblingsByClause

      public boolean hasOrderSiblingsByClause()
      Determines whether the ORDER SIBLINGS BY clause is defined.
      Returns:
      true if the query that got parsed had the ORDER SIBLINGS BY clause

    • hasSpaceAfterConnectByClause

      public boolean hasSpaceAfterConnectByClause()
      Determines whether a whitespace was found after the CONNECT BY clause. In some cases, the space is owned by a child of the hierarchical query clause.
      Returns:
      true if there was a whitespace after the CONNECT BY clause and owned by this expression; false otherwise

    • hasSpaceAfterStartWithClause

      public boolean hasSpaceAfterStartWithClause()
      Determines whether a whitespace was found after the START WITH clause. In some cases, the space is owned by a child of the hierarchical query clause.
      Returns:
      true if there was a whitespace after the START WITH clause and owned by this expression; false otherwise

    • hasStartWithClause

      public boolean hasStartWithClause()
      Determines whether the START WITH clause is defined.
      Returns:
      true if the query that got parsed had the START WITH clause

    • 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