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

java.lang.Object
org.eclipse.persistence.jpa.internal.jpql.parser.StringExpression
org.eclipse.persistence.jpa.internal.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.internal.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.

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 ]

Since:

2.3

Version:

2.3

Author:

Pascal Filion

Nested Class Summary

static class

OrderByItem.Ordering This enumeration lists all the possible choices for ordering an item.

Field Summary

private AbstractExpression	expression The Expression representing the order by expression.
private boolean	hasSpaceAfterExpression Determines whether a whitespace was parsed after the order by expression.
private OrderByItem.Ordering	ordering The keyword ASC specifies that ascending ordering be used; the keyword DESC specifies that descending ordering be used.

Fields inherited from class org.eclipse.persistence.jpa.internal.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.internal.jpql.parser.Expression

ABS, ALL, AND, ANY, AS, ASC, AVG, BETWEEN, BIT_LENGTH, BOTH, CASE, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, CONCAT, COUNT, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, DELETE, DELETE_FROM, DESC, DIFFERENT, DISTINCT, DIVISION, ELSE, EMPTY, END, ENTRY, EQUAL, ESCAPE, EXISTS, FALSE, FETCH, FROM, FUNC, GREATER_THAN, GREATER_THAN_OR_EQUAL, GROUP_BY, HAVING, IN, INDEX, INNER, INNER_JOIN, INNER_JOIN_FETCH, IS, IS_EMPTY, IS_NOT_EMPTY, IS_NOT_NULL, IS_NULL, JOIN, JOIN_FETCH, KEY, 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_EXISTS, NOT_IN, NOT_LIKE, NOT_MEMBER, NOT_MEMBER_OF, NULL, NULLIF, OBJECT, OF, OR, ORDER_BY, OUTER, PLUS, POSITION, POSITIONAL_PARAMETER, QUOTE, SELECT, SET, SIZE, SOME, SQRT, SUBSTRING, SUM, THEN, TRAILING, TREAT, TRIM, TRUE, TYPE, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE

Constructor Summary

OrderByItem(AbstractExpression parent)
Creates a new OrderByItem.

Method Summary

void	accept(ExpressionVisitor visitor) Visits this Expression by the given visitor.
void	acceptChildren(ExpressionVisitor visitor) Visits the children of this Expression.
(package private) void	addChildrenTo(java.util.Collection<Expression> children) Adds the children of this Expression to the given collection.
(package private) void	addOrderedChildrenTo(java.util.List<StringExpression> children) Adds the StringExpressions representing this Expression.
Expression	getExpression() Returns the Expression that represents the order by expression.
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	hasSpaceAfterExpression() Determines whether a whitespace was parsed after the order by expression.
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.
(package private) 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.
(package private) void	parse(WordParser wordParser, boolean tolerant) Parses the query by starting at the current position, which is part of the given WordParser.
(package private) void	toParsedText(java.lang.StringBuilder writer, boolean includeVirtual) Generates a string representation of this Expression.

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

buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, children, expressionFactory, expressionFactoryForIdentifier, findQueryBNF, getChildren, getJPAVersion, getParent, getRoot, getText, handleAggregate, identifierRole, identifiers, identifiers, identifierVersion, isAncestor, isIdentifier, isNull, isTolerant, isUnknown, isVirtual, orderedChildren, parse, parseSingleExpression, populatePosition, queryBNF, readdLeadingSpaces, 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

Field Detail

expression

private AbstractExpression expression

The Expression representing the order by expression.

hasSpaceAfterExpression

private boolean hasSpaceAfterExpression

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

ordering

private OrderByItem.Ordering ordering

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

Constructor Detail

OrderByItem

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 visitor 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() or Expression.getChildren() is called.

This does not traverse the Expression sub-hierarchy, use an subclass of AbstractTraverseChildrenVisitor in order to traverse the entire sub-hierarchy.

Parameters:

visitor - The visitor to visit the children of this object.

addChildrenTo

void addChildrenTo(java.util.Collection<Expression> children)

Adds the children of this Expression to the given collection.

Overrides:

addChildrenTo in class AbstractExpression

Parameters:

children - The collection used to store the children

addOrderedChildrenTo

void addOrderedChildrenTo(java.util.List<StringExpression> children)

Adds the StringExpressions representing this Expression.

Overrides:

addOrderedChildrenTo in class AbstractExpression

Parameters:

children - The list used to store the string representation of this Expression

getExpression

public Expression getExpression()

Returns the Expression that represents the order by expression.

Returns:

The expression that was parsed representing the order by expression

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.

Specified by:

getQueryBNF in class AbstractExpression

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

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

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

isParsingComplete

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

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

void toParsedText(java.lang.StringBuilder writer,
                  boolean includeVirtual)

Generates a string representation of this Expression.

Specified by:

toParsedText in class AbstractExpression

Parameters:

writer - The buffer used to append this Expression's string representation

includeVirtual - Determines whether to include any characters that are considered virtual, i.e. that was parsed when the query is incomplete and is needed for functionality like content assist