org.eclipse.persistence.jpa.jpql.parser
Class NullIfExpression

java.lang.Object
  org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
      org.eclipse.persistence.jpa.jpql.parser.AbstractEncapsulatedExpression
          org.eclipse.persistence.jpa.jpql.parser.AbstractDoubleEncapsulatedExpression
              org.eclipse.persistence.jpa.jpql.parser.NullIfExpression

All Implemented Interfaces:

Expression

public final class NullIfExpression
extends AbstractDoubleEncapsulatedExpression

NULLIF returns the first expression if the two expressions are not equal. If the expressions are equal, NULLIF returns a null value of the type of the first expression.

NULLIF is equivalent to a searched CASE expression in which the two expressions are equal and the resulting expression is NULL.

Returns the same type as the first expression.

BNF: nullif_expression::= NULLIF(scalar_expression, scalar_expression)

Version:

2.4

Author:

Pascal Filion

Since:

2.3

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, ASC, AVG, BETWEEN, BIT_LENGTH, BOTH, CASE, CAST, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, COLUMN, CONCAT, 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, 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, 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_FIRST, NULLS_LAST, OBJECT, OF, ON, OPERATOR, OR, ORDER_BY, OUTER, PLUS, POSITION, POSITIONAL_PARAMETER, QUOTE, REGEXP, SELECT, SET, SIZE, SOME, SQL, SQRT, SUBSTRING, SUM, TABLE, THEN, TRAILING, TREAT, TRIM, TRUE, TYPE, UNION, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE

Constructor Summary

NullIfExpression(AbstractExpression parent)
Creates a new NullIfExpression.

Method Summary

void	accept(ExpressionVisitor visitor) Visits this Expression by the given visitor.
JPQLQueryBNF	getQueryBNF() Returns the BNF of this Expression.
java.lang.String	parameterExpressionBNF(int index) Returns the BNF to be used to parse one of the encapsulated expression.
protected java.lang.String	parseIdentifier(WordParser wordParser) Parses the identifier of this expression.

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

acceptChildren, addChildrenTo, addOrderedEncapsulatedExpressionTo, buildCollectionExpression, findQueryBNF, getFirstExpression, getSecondExpression, hasComma, hasEncapsulatedExpression, hasFirstExpression, hasSecondExpression, hasSpaceAfterComma, isParsingComplete, isSecondExpressionOptional, parseEncapsulatedExpression, removeEncapsulatedExpression, toParsedTextEncapsulatedExpression

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

addOrderedChildrenTo, areLogicalIdentifiersSupported, getActualIdentifier, getIdentifier, hasLeftParenthesis, hasRightParenthesis, hasSpaceAfterIdentifier, parse, shouldParseRightParenthesis, toParsedText

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

NullIfExpression

public NullIfExpression(AbstractExpression parent)

Creates a new NullIfExpression.

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

getQueryBNF

public JPQLQueryBNF getQueryBNF()

Returns the BNF of this Expression.

Returns:

The JPQLQueryBNF, which represents the grammar of this Expression

parameterExpressionBNF

public java.lang.String parameterExpressionBNF(int index)

Returns the BNF to be used to parse one of the encapsulated expression.

Specified by:

parameterExpressionBNF in class AbstractDoubleEncapsulatedExpression

Parameters:

index - The position of the encapsulated Expression that needs to be parsed within the parenthesis, which starts at position 0

Returns:

The BNF to be used to parse one of the encapsulated expression

parseIdentifier

protected java.lang.String parseIdentifier(WordParser wordParser)

Parses the identifier of this expression.

Specified by:

parseIdentifier in class AbstractEncapsulatedExpression

Returns:

The identifier for this expression