org.eclipse.persistence.jpa.jpql.model.query
Class ResultVariableStateObject

java.lang.Object
  org.eclipse.persistence.jpa.jpql.model.query.AbstractStateObject
      org.eclipse.persistence.jpa.jpql.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]

Version:

2.4

See Also:

ResultVariable

Author:

Pascal Filion

Since:

2.4

Field Summary

static java.lang.String	AS_PROPERTY Notifies the visibility of the AS identifier has changed.
static java.lang.String	RESULT_VARIABLE_PROPERTY Notifies the result variable property has changed.
static java.lang.String	STATE_OBJECT_PROPERTY Notifies the select state object property has changed.

Constructor Summary

ResultVariableStateObject(SelectClauseStateObject parent)
Creates a new ResultVariableStateObject.

ResultVariableStateObject(SelectClauseStateObject parent, StateObject stateObject, boolean as, java.lang.String resultVariable)
Creates a new ResultVariableStateObject.

ResultVariableStateObject(SelectClauseStateObject parent, StateObject stateObject, java.lang.String resultVariable)
Creates a new ResultVariableStateObject.

Method Summary

void	accept(StateObjectVisitor visitor) Visits this StateObject by the given visitor.
ResultVariableStateObject	addAs() Makes sure the AS identifier is used.
protected void	addChildren(java.util.List<StateObject> children) Adds the children of this StateObject to the given list.
ResultVariable	getExpression() Returns the actual parsed object if this StateObject representation of the JPQL query was created by parsing an existing JPQL query.
SelectClauseStateObject	getParent() Returns the parent of this StateObject.
java.lang.String	getResultVariable() Returns the result variable identifies the select expression, which can be used in the ORDER BY clause.
StateObject	getStateObject() Returns the StateObject representing a single select expression.
boolean	hasAs() Determines whether the AS identifier is used.
boolean	hasResultVariable() Determines whether the result variable has been defined.
boolean	hasStateObject() Determines whether the select item has been defined.
protected void	initialize() Initializes this state object.
boolean	isEquivalent(StateObject stateObject) Determines whether the given StateObject is equivalent to this one, i.e. the information of both StateObject is the same.
void	parse(java.lang.String jpqlFragment) Parses the given JPQL fragment, which represents a single select expression, and creates the StateObject.
void	removeAs() Makes sure the AS identifier is not used.
void	setAs(boolean as) Sets whether the AS identifier should be used.
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.
void	setResultVariable(java.lang.String resultVariable) Sets the result variable that identifies the select expression, which can be used in the ORDER BY clause.
void	setStateObject(StateObject stateObject) Sets the StateObject representing a single select expression.
void	toggleAs() Toggles the visibility of the AS identifier; either adds it if it's not present otherwise removes it if it's present.
protected void	toTextInternal(java.lang.Appendable writer) 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.

Methods inherited from class org.eclipse.persistence.jpa.jpql.model.query.AbstractStateObject

acceptUnknownVisitor, acceptUnknownVisitor, addProblems, addPropertyChangeListener, areEquivalent, buildProblem, buildProblem, buildStateObject, buildStateObjects, checkParent, children, decorate, equals, findIdentificationVariable, firePropertyChanged, getChangeSupport, getDeclaration, getDecorator, getGrammar, getManagedTypeProvider, getQueryBuilder, getRoot, getType, getType, getTypeHelper, getTypeRepository, hashCode, isDecorated, parent, parent, parent, removePropertyChangeListener, setExpression, setParent, toString, toString, toStringInternal, toStringItems, toText

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

AS_PROPERTY

public static final java.lang.String AS_PROPERTY

Notifies the visibility of the AS identifier has changed.

See Also:

Constant Field Values

RESULT_VARIABLE_PROPERTY

public static final java.lang.String RESULT_VARIABLE_PROPERTY

Notifies the result variable property has changed.

See Also:

Constant Field Values

STATE_OBJECT_PROPERTY

public static final java.lang.String STATE_OBJECT_PROPERTY

Notifies the select state object property has changed.

See Also:

Constant Field Values

Constructor Detail

ResultVariableStateObject

public ResultVariableStateObject(SelectClauseStateObject parent)

Creates a new ResultVariableStateObject.

Parameters:

parent - The parent of this state object, which cannot be null

Throws:

java.lang.NullPointerException - The given parent cannot be null

ResultVariableStateObject

public ResultVariableStateObject(SelectClauseStateObject parent,
                                 StateObject stateObject,
                                 boolean as,
                                 java.lang.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:

java.lang.NullPointerException - The given parent cannot be null

ResultVariableStateObject

public ResultVariableStateObject(SelectClauseStateObject parent,
                                 StateObject stateObject,
                                 java.lang.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:

java.lang.NullPointerException - The given parent cannot be null

Method Detail

accept

public void accept(StateObjectVisitor visitor)

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(java.util.List<StateObject> children)

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()

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()

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 java.lang.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()

Initializes this state object.

Overrides:

initialize in class AbstractStateObject

isEquivalent

public boolean isEquivalent(StateObject 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(java.lang.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(java.lang.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(java.lang.Appendable writer)
                       throws java.io.IOException

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:

java.io.IOException - This should never happens, it is only required because Appendable is used instead of any concrete class