Class IdentificationVariableDeclaration

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

public final class IdentificationVariableDeclaration extends AbstractExpression
An identification variable is a valid identifier declared in the FROM clause of a query. All identification variables must be declared in the FROM clause. Identification variables cannot be declared in other clauses. An identification variable must not be a reserved identifier or have the same name as any entity in the same persistence unit: Identification variables are case insensitive. An identification variable evaluates to a value of the type of the expression used in declaring the variable.
BNF: identification_variable_declaration ::= range_variable_declaration { join | fetch_join }*
Since:
2.3
Version:
2.5
  • Constructor Details

    • IdentificationVariableDeclaration

      public IdentificationVariableDeclaration(AbstractExpression parent)
      Creates a new IdentificationVariableDeclaration.
      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 join expression.
      Returns:
      The single join expression 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
    • getJoins

      public Expression getJoins()
      Returns the unique join (fetch join) or the list of joins (fetch joins) expression.
      Returns:
      The JOIN expression(s) or a null expression if none was declared
    • 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
    • getRangeVariableDeclaration

      public Expression getRangeVariableDeclaration()
      Returns the variable declaration, which is the abstract schema name and the identification variable.
      Returns:
      The Expression representing the range variable declaration
    • hasJoins

      public boolean hasJoins()
      Determines whether this declaration has any join expressions.
      Returns:
      true if at least one join expression was specified; false otherwise
    • hasRangeVariableDeclaration

      public boolean hasRangeVariableDeclaration()
      Determines whether the range variable declaration was parsed.
      Returns:
      true if the range variable declaration was parsed; false otherwise
    • hasSpace

      public boolean hasSpace()
      Determines whether there is a space after the range variable declaration.
      Returns:
      true if the range variable declaration is followed by a space, 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
    • 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
    • shouldParseWithFactoryFirst

      protected boolean shouldParseWithFactoryFirst()
      Description copied from class: AbstractExpression
      Determines whether the parsing of the query should be performed using the factories first or it should automatically fallback to the fallback factory.
      Overrides:
      shouldParseWithFactoryFirst in class AbstractExpression
      Returns:
      true is returned by default so the factories are used before falling back
    • 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