Module org.eclipse.persistence.jpa.jpql
Package org.eclipse.persistence.jpa.jpql.tools.model.query

Class ResultVariableStateObject

java.lang.Object
org.eclipse.persistence.jpa.jpql.tools.model.query.AbstractStateObject
org.eclipse.persistence.jpa.jpql.tools.model.query.ResultVariableStateObject
All Implemented Interfaces:
StateObject
public class ResultVariableStateObject extends AbstractStateObject
A result variable may be used to name a select item in the query result.

BNF: select_item ::= select_expression [[AS] result_variable]

Since:
2.4
Version:
2.4
See Also:

  • Field Details

    • AS_PROPERTY

      public static final String AS_PROPERTY
      Notifies the visibility of the AS identifier has changed.
      See Also:

    • RESULT_VARIABLE_PROPERTY

      public static final String RESULT_VARIABLE_PROPERTY
      Notifies the result variable property has changed.
      See Also:

    • STATE_OBJECT_PROPERTY

      public static final String STATE_OBJECT_PROPERTY
      Notifies the select state object property has changed.
      See Also:

  • Constructor Details

    • ResultVariableStateObject

      public ResultVariableStateObject(SelectClauseStateObject parent)
      Creates a new ResultVariableStateObject.
      Parameters:
      parent - The parent of this state object, which cannot be null
      Throws:
      NullPointerException - The given parent cannot be null

    • ResultVariableStateObject

      public ResultVariableStateObject(SelectClauseStateObject parent, StateObject stateObject, boolean as, String resultVariable)
      Creates a new ResultVariableStateObject.
      Parameters:
      parent - The parent of this state object, which cannot be null
      stateObject - The StateObject representing the select item
      as - Determines whether the AS identifier is used or not
      resultVariable - The variable identifying the select item
      Throws:
      NullPointerException - The given parent cannot be null

    • ResultVariableStateObject

      public ResultVariableStateObject(SelectClauseStateObject parent, StateObject stateObject, String resultVariable)
      Creates a new ResultVariableStateObject.
      Parameters:
      parent - The parent of this state object, which cannot be null
      stateObject - The StateObject representing the select item
      resultVariable - The variable identifying the select item
      Throws:
      NullPointerException - The given parent cannot be null

  • Method Details

    • accept

      public void accept(StateObjectVisitor visitor)
      Description copied from interface: StateObject
      Visits this StateObject by the given visitor.
      Parameters:
      visitor - The visitor to visit this object

    • addAs

      public ResultVariableStateObject addAs()
      Makes sure the AS identifier is used.
      Returns:
      This object

    • addChildren

      protected void addChildren(List<StateObject> children)
      Description copied from class: AbstractStateObject
      Adds the children of this StateObject to the given list.
      Overrides:
      addChildren in class AbstractStateObject
      Parameters:
      children - The list used to store the children

    • getExpression

      public ResultVariable getExpression()
      Description copied from interface: StateObject
      Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
      Specified by:
      getExpression in interface StateObject
      Overrides:
      getExpression in class AbstractStateObject
      Returns:
      The parsed object when a JPQL query is parsed and converted into a StateObject or null when the JPQL query is manually created (i.e. not from a string)

    • getParent

      public SelectClauseStateObject getParent()
      Description copied from interface: StateObject
      Returns the parent of this StateObject.
      Specified by:
      getParent in interface StateObject
      Overrides:
      getParent in class AbstractStateObject
      Returns:
      Returns the parent of this StateObject, which is null only when this is the root of the hierarchy

    • getResultVariable

      public String getResultVariable()
      Returns the result variable identifies the select expression, which can be used in the ORDER BY clause.
      Returns:
      The unique identifier declaring the select expression

    • getStateObject

      public StateObject getStateObject()
      Returns the StateObject representing a single select expression.
      Returns:
      The StateObject representing a single select expression

    • hasAs

      public boolean hasAs()
      Determines whether the AS identifier is used.
      Returns:
      true if the AS identifier is used; false otherwise

    • hasResultVariable

      public boolean hasResultVariable()
      Determines whether the result variable has been defined.
      Returns:
      true if the result variable is defined; false otherwise

    • hasStateObject

      public boolean hasStateObject()
      Determines whether the select item has been defined.
      Returns:
      true if there the selected expression has been defined; false if it's missing

    • initialize

      protected void initialize()
      Description copied from class: AbstractStateObject
      Initializes this state object.
      Overrides:
      initialize in class AbstractStateObject

    • isEquivalent

      public boolean isEquivalent(StateObject stateObject)
      Description copied from interface: StateObject
      Determines whether the given StateObject is equivalent to this one, i.e. the information of both StateObject is the same.
      Specified by:
      isEquivalent in interface StateObject
      Overrides:
      isEquivalent in class AbstractStateObject
      Parameters:
      stateObject - The StateObject to compare its content to this one
      Returns:
      true if both object are equivalent; false otherwise

    • parse

      public void parse(String jpqlFragment)
      Parses the given JPQL fragment, which represents a single select expression, and creates the StateObject.
      Parameters:
      jpqlFragment - The portion of the query representing a single select expression

    • removeAs

      public void removeAs()
      Makes sure the AS identifier is not used.

    • setAs

      public void setAs(boolean as)
      Sets whether the AS identifier should be used.
      Parameters:
      as - true if the AS identifier should be used part; false otherwise

    • setExpression

      public void setExpression(ResultVariable expression)
      Keeps a reference of the parsed object object, which should only be done when this object is instantiated during the conversion of a parsed JPQL query into StateObjects.
      Parameters:
      expression - The parsed object representing a result variable expression

    • setResultVariable

      public void setResultVariable(String resultVariable)
      Sets the result variable that identifies the select expression, which can be used in the ORDER BY clause.
      Parameters:
      resultVariable - The unique identifier declaring the select expression

    • setStateObject

      public void setStateObject(StateObject stateObject)
      Sets the StateObject representing a single select expression.
      Parameters:
      stateObject - The StateObject representing a single select expression

    • toggleAs

      public void toggleAs()
      Toggles the visibility of the AS identifier; either adds it if it's not present otherwise removes it if it's present.

    • toTextInternal

      protected void toTextInternal(Appendable writer) throws IOException
      Description copied from class: AbstractStateObject
      Prints out a string representation of this StateObject, which should not be used to define a true string representation of a JPQL query but should be used for debugging purposes.
      Specified by:
      toTextInternal in class AbstractStateObject
      Parameters:
      writer - The writer used to print out the string representation
      Throws:
      IOException - This should never happens, it is only required because Appendable is used instead of any concrete class