org.eclipse.persistence.jpa.jpql.parser

Class OrderByItem

java.lang.Object

org.eclipse.persistence.jpa.jpql.parser.AbstractExpression

org.eclipse.persistence.jpa.jpql.parser.OrderByItem

All Implemented Interfaces:

Expression

public final class OrderByItem
extends AbstractExpression

An orderby_item must be one of the following:

1. A state_field_path_expression that evaluates to an orderable state field of an entity or embeddable class abstract schema type designated in the SELECT clause by one of the following:
   • A general_identification_variable
   • A single_valued_object_path_expression
2. A state_field_path_expression that evaluates to the same state field of the same entity or embeddable abstract schema type as a state_field_path_expression in the SELECT clause
3. A result_variable that refers to an orderable item in the SELECT clause for which the same result_variable has been specified. This may be the result of an aggregate_expression, a scalar_expression, or a state_field_path_expression in the SELECT clause.

The keyword ASC specifies that ascending ordering be used for the associated orderby_item; the keyword DESC specifies that descending ordering be used. Ascending ordering is the default.

The keyword NULLS FIRST specifies that nulls first ordering be used for the associated orderby_item; the keyword NULLS LAST specifies that nulls last ordering be used. Ascending ordering is the default.

JPA 1.0:

BNF: orderby_item ::= state_field_path_expression [ ASC | DESC ]

JPA 2.0

BNF: orderby_item ::= state_field_path_expression | result_variable [ ASC | DESC ]

EclipseLink 2.4:

BNF: orderby_item ::= state_field_path_expression | result_variable [ ASC | DESC ] [ NULLS FIRST | NULLS LAST ]

Version:

2.5

Author:

Pascal Filion

Since:

2.3

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	OrderByItem.NullOrdering This enumeration lists all the possible choices for ordering nulls in an item.
static class	OrderByItem.Ordering This enumeration lists all the possible choices for ordering an item.

Field Summary

Fields inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression

COMMA, DOT, DOUBLE_QUOTE, LEFT_CURLY_BRACKET, LEFT_PARENTHESIS, NOT_DEFINED, RIGHT_CURLY_BRACKET, RIGHT_PARENTHESIS, SINGLE_QUOTE, SPACE, UNDERSCORE

Fields inherited from interface org.eclipse.persistence.jpa.jpql.parser.Expression

ABS, ALL, AND, ANY, AS, AS_OF, ASC, AVG, BETWEEN, BIT_LENGTH, BOTH, CASE, CAST, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, COLUMN, CONCAT, CONNECT_BY, COUNT, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, DELETE, DELETE_FROM, DESC, DIFFERENT, DISTINCT, DIVISION, ELSE, EMPTY, END, ENTRY, EQUAL, ESCAPE, EXCEPT, EXISTS, EXTRACT, FALSE, FETCH, FIRST, FROM, FUNC, FUNCTION, GREATER_THAN, GREATER_THAN_OR_EQUAL, GROUP_BY, HAVING, IN, INDEX, INNER, INNER_JOIN, INNER_JOIN_FETCH, INTERSECT, IS, IS_EMPTY, IS_NOT_EMPTY, IS_NOT_NULL, IS_NULL, JOIN, JOIN_FETCH, KEY, LAST, LEADING, LEFT, LEFT_JOIN, LEFT_JOIN_FETCH, LEFT_OUTER_JOIN, LEFT_OUTER_JOIN_FETCH, LENGTH, LIKE, LOCATE, LOWER, LOWER_THAN, LOWER_THAN_OR_EQUAL, MAX, MEMBER, MEMBER_OF, MIN, MINUS, MOD, MULTIPLICATION, NAMED_PARAMETER, NEW, NOT, NOT_BETWEEN, NOT_EQUAL, NOT_EXISTS, NOT_IN, NOT_LIKE, NOT_MEMBER, NOT_MEMBER_OF, NULL, NULLIF, NULLS, NULLS_FIRST, NULLS_LAST, OBJECT, OF, ON, OPERATOR, OR, ORDER_BY, ORDER_SIBLINGS_BY, OUTER, PLUS, POSITION, POSITIONAL_PARAMETER, QUOTE, REGEXP, SCN, SELECT, SET, SIZE, SOME, SQL, SQRT, START_WITH, SUBSTRING, SUM, TABLE, THEN, TIMESTAMP, TRAILING, TREAT, TRIM, TRUE, TYPE, UNION, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE

Constructor Summary

Constructors

Constructor and Description
OrderByItem(AbstractExpression parent) Creates a new OrderByItem.

Method Summary

Modifier and Type	Method and Description
void	accept(ExpressionVisitor visitor) Visits this Expression by the given visitor.
void	acceptChildren(ExpressionVisitor visitor) Visits the children of this Expression.
protected void	addChildrenTo(java.util.Collection<Expression> children) Adds the children of this AbstractExpression to the given collection.
protected void	addOrderedChildrenTo(java.util.List<Expression> children) Adds the children of this AbstractExpression to the given list.
JPQLQueryBNF	findQueryBNF(Expression expression) Retrieves the JPQLQueryBNF that represents the fragment of this Expression that was used when parsing the given Expression.
java.lang.String	getActualNullOrdering() Returns the actual null ordering identifier found in the string representation of the JPQL query, which has the actual case that was used.
java.lang.String	getActualOrdering() Returns the actual ordering identifier found in the string representation of the JPQL query, which has the actual case that was used.
Expression	getExpression() Returns the Expression that represents the order by expression.
OrderByItem.NullOrdering	getNullOrdering() Returns the enum constant representing the null ordering type.
OrderByItem.Ordering	getOrdering() Returns the enum constant representing the ordering type.
JPQLQueryBNF	getQueryBNF() Returns the BNF of this Expression.
boolean	hasExpression() Determines whether the order by expression was parsed.
boolean	hasNulls() Determines whether the NULLS identifier was parsed.
boolean	hasOrdering() Determines whether ASC or DESC was parsed.
boolean	hasSpaceAfterExpression() Determines whether a whitespace was parsed after the order by expression.
boolean	hasSpaceAfterNulls() Determines whether a whitespace was parsed after the NULLS identifier.
boolean	hasSpaceAfterOrdering() Determines whether a whitespace was parsed after the ordering.
boolean	isAscending() Determines whether the ordering was specified as being ascendant.
boolean	isDefault() Determines whether the ordering was not specified.
boolean	isDescending() Determines whether the ordering was specified as being descendant.
boolean	isNullsFirst() Determines whether the ordering was specified as being nulls first.
boolean	isNullsLast() Determines whether the ordering was specified as being nulls first.
protected boolean	isParsingComplete(WordParser wordParser, java.lang.String word, Expression expression) Determines whether the parsing is complete based on what is left in the given text.
protected void	parse(WordParser wordParser, boolean tolerant) Parses the query by starting at the current position, which is part of the given WordParser.
protected void	toParsedText(java.lang.StringBuilder writer, boolean actual) Generates a string representation of this Expression, including its children, if it has any.

Methods inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression

acceptUnknownVisitor, acceptUnknownVisitor, buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, calculatePosition, children, findFallBackExpressionFactory, getExpressionFactory, getExpressionRegistry, getGrammar, getIdentifierVersion, getJPAVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, getText, handleAggregate, handleCollection, isAncestor, isIdentifier, isNull, isTolerant, isUnknown, isVirtual, orderedChildren, parse, parseUsingExpressionFactory, populatePosition, rebuildActualText, rebuildParsedText, setParent, setText, shouldParseWithFactoryFirst, shouldSkipLiteral, toActualText, toParsedText, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

OrderByItem

public OrderByItem(AbstractExpression parent)

Creates a new OrderByItem.

Parameters:

parent - The parent of this expression

Method Detail

accept

public void accept(ExpressionVisitor visitor)

Visits this Expression by the given visitor.

Parameters:

visitor - The ExpressionVisitor to visit this object

acceptChildren

public void acceptChildren(ExpressionVisitor visitor)

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(java.util.Collection<Expression> children)

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(java.util.List<Expression> children)

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)

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

getActualNullOrdering

public java.lang.String getActualNullOrdering()

Returns the actual null ordering identifier found in the string representation of the JPQL query, which has the actual case that was used.

Returns:

The null ordering identifier that was actually parsed, if one was present, otherwise an empty string is returned

getActualOrdering

public java.lang.String getActualOrdering()

Returns the actual ordering identifier found in the string representation of the JPQL query, which has the actual case that was used.

Returns:

The ordering identifier that was actually parsed, if one was present, otherwise an empty string is returned

getExpression

public Expression getExpression()

Returns the Expression that represents the order by expression.

Returns:

The expression that was parsed representing the order by expression

getNullOrdering

public OrderByItem.NullOrdering getNullOrdering()

Returns the enum constant representing the null ordering type.

Returns:

The constant representing the null ordering, in the case the ordering was not parsed, then OrderByItem.NullOrdering.DEFAULT is returned

getOrdering

public OrderByItem.Ordering getOrdering()

Returns the enum constant representing the ordering type.

Returns:

The constant representing the ordering, in the case the ordering was not parsed, then OrderByItem.Ordering.DEFAULT is returned

getQueryBNF

public JPQLQueryBNF getQueryBNF()

Returns the BNF of this Expression.

Returns:

The JPQLQueryBNF, which represents the grammar of this Expression

hasExpression

public boolean hasExpression()

Determines whether the order by expression was parsed.

Returns:

true if the order by expression was parsed; false otherwise

hasNulls

public boolean hasNulls()

Determines whether the NULLS identifier was parsed.

Returns:

true if the NULLS identifier was parsed; false otherwise

hasOrdering

public boolean hasOrdering()

Determines whether ASC or DESC was parsed.

Returns:

true if the ordering status was parsed; false otherwise

Since:

2.5

hasSpaceAfterExpression

public boolean hasSpaceAfterExpression()

Determines whether a whitespace was parsed after the order by expression.

Returns:

true if there was a whitespace after the order by expression; false otherwise

hasSpaceAfterNulls

public boolean hasSpaceAfterNulls()

Determines whether a whitespace was parsed after the NULLS identifier. If the composite identifier was fully parsed - NULLS FIRST or NULLS LAST - then this is always true, but if only NULLS was parsed, then this can be useful to determine if there was a space after.

Returns:

true if there was a whitespace after the NULLS identifier; false otherwise

hasSpaceAfterOrdering

public boolean hasSpaceAfterOrdering()

Determines whether a whitespace was parsed after the ordering.

Returns:

true if there was a whitespace after the ordering; false otherwise

isAscending

public boolean isAscending()

Determines whether the ordering was specified as being ascendant.

Returns:

true if ASC was parsed; false otherwise

isDefault

public boolean isDefault()

Determines whether the ordering was not specified.

Returns:

true if no ordering was parsed; false otherwise

isDescending

public boolean isDescending()

Determines whether the ordering was specified as being descendant.

Returns:

true if DESC was parsed; false otherwise

isNullsFirst

public boolean isNullsFirst()

Determines whether the ordering was specified as being nulls first.

Returns:

true if NULLS FIRST was parsed; false otherwise

isNullsLast

public boolean isNullsLast()

Determines whether the ordering was specified as being nulls first.

Returns:

true if NULLS LAST was parsed; false otherwise

isParsingComplete

protected boolean isParsingComplete(WordParser wordParser,
                                    java.lang.String word,
                                    Expression expression)

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)

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(java.lang.StringBuilder writer,
                            boolean actual)

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