Class RangeVariableDeclaration

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

public final class RangeVariableDeclaration extends AbstractExpression
Range variable declarations allow the developer to designate a "root" for objects which may not be reachable by navigation. In order to select values by comparing more than one instance of an entity abstract schema type, more than one identification variable ranging over the abstract schema type is needed in the FROM clause.

JPA:

BNF: range_variable_declaration ::= abstract_schema_name [AS] identification_variable

EclipseLink 2.4:

BNF: range_variable_declaration ::= { root_object } [AS] identification_variable
BNF: root_object ::= abstract_schema_name | (subquery)
Since:
2.3
Version:
2.5
  • Constructor Details

    • RangeVariableDeclaration

      public RangeVariableDeclaration(AbstractExpression parent)
      Creates a new RangeVariableDeclaration.
      Parameters:
      parent - The parent of this expression
    • RangeVariableDeclaration

      public RangeVariableDeclaration(String entityName, String variableName)
      Creates a new RangeVariableDeclaration, which is used as a virtual declaration.
      Parameters:
      entityName - The name of the entity to be accessible with the given variable name
      variableName - The identification variable used to navigate to the entity
  • 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
    • getActualAsIdentifier

      public String getActualAsIdentifier()
      Returns the actual AS found in the string representation of the JPQL query, which has the actual case that was used.
      Returns:
      The AS identifier that was actually parsed, or an empty string if it was not parsed
    • getIdentificationVariable

      public Expression getIdentificationVariable()
      Returns the Expression that represents the identification variable.
      Returns:
      The expression that was parsed representing the identification variable
    • 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
    • getRootObject

      public Expression getRootObject()
      Returns the Expression that represents the "root" object.
      Returns:
      The expression that was parsed representing the "root" object
    • hasAs

      public boolean hasAs()
      Determines whether the identifier AS was parsed.
      Returns:
      true if the identifier AS was parsed; false otherwise
    • hasIdentificationVariable

      public boolean hasIdentificationVariable()
      Determines whether the identification variable was parsed.
      Returns:
      true if the identification variable was parsed; false otherwise
    • hasRootObject

      public boolean hasRootObject()
      Determines whether the "root" object was parsed.
      Returns:
      true if the "root" object was parsed; false otherwise
    • hasSpaceAfterAs

      public boolean hasSpaceAfterAs()
      Determines whether a whitespace was parsed after AS.
      Returns:
      true if there was a whitespace after AS; false otherwise
    • hasSpaceAfterRootObject

      public boolean hasSpaceAfterRootObject()
      Determines whether a whitespace was parsed after the "root" object.
      Returns:
      true if there was a whitespace after "root" object; false otherwise
    • hasVirtualIdentificationVariable

      public boolean hasVirtualIdentificationVariable()
      Determines whether this identification variable is virtual, meaning it's not part of the query but is required for proper navigability.
      Returns:
      true if this identification variable was virtually created to fully qualify path expression; false if it was parsed
    • 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
    • setVirtualIdentificationVariable

      public void setVirtualIdentificationVariable(String variableName)
      Sets a virtual identification variable because the "root" object was parsed without one. This is valid in an UPDATE and DELETE queries. Example:

      UPDATE DateTime SET date = CURRENT_DATE

      is equivalent to

      UPDATE DateTime d SET d.date = CURRENT_DATE

      Parameters:
      variableName - A virtual identification variable that will identify the "root" object
    • setVirtualIdentificationVariable

      public void setVirtualIdentificationVariable(String variableName, String path)
      Sets a virtual identification variable to qualify the "root" object. The "root" object is a derived path that does not start with an identification variable. Example:

      UPDATE Employee SET firstName = 'MODIFIED' WHERE (SELECT COUNT(m) FROM managedEmployees m) > 0

      'managedEmployees' is a derived path and will become qualified with the given virtual identification variable.

      Parameters:
      variableName - The identification variable that was generated to qualify the "root" object
      path - The path that was parsed as a "root" object
    • 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