Class NullExpression
java.lang.Object
org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.jpql.parser.NullExpression
- All Implemented Interfaces:
Expression
A
null
Expression
is used instead of a true null
, which allows
operations to be performed without doing a null
check first.- Since:
- 2.3
- Version:
- 2.5
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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, CEILING, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, COLUMN, CONCAT, CONNECT_BY, COUNT, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, DATE, DATETIME, DELETE, DELETE_FROM, DESC, DIFFERENT, DISTINCT, DIVISION, ELSE, EMPTY, END, ENTRY, EQUAL, ESCAPE, EXCEPT, EXISTS, EXP, EXTRACT, FALSE, FETCH, FIRST, FLOOR, 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, LN, LOCAL, 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, POWER, QUOTE, REGEXP, ROUND, SCN, SELECT, SET, SIGN, SIZE, SOME, SQL, SQRT, START_WITH, SUBSTRING, SUM, TABLE, THEN, TIME, TIMESTAMP, TRAILING, TREAT, TRIM, TRUE, TYPE, UNION, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE
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Constructor Summary
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Method Summary
Modifier and TypeMethodDescriptionvoid
accept
(ExpressionVisitor visitor) Visits thisExpression
by the givenvisitor
.void
acceptChildren
(ExpressionVisitor visitor) Visits the children of thisExpression
.findQueryBNF
(Expression expression) Retrieves theJPQLQueryBNF
that represents the fragment of thisExpression
that was used when parsing the givenExpression
.Returns the BNF of thisExpression
.boolean
isNull()
Determines whether this expression is anull
Expression
or any other subclass.protected void
parse
(WordParser wordParser, boolean tolerant) Parses the query by starting at the current position, which is part of the givenWordParser
.protected void
toParsedText
(StringBuilder writer, boolean actual) Generates a string representation of thisExpression
, including its children, if it has any.Methods inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
acceptUnknownVisitor, acceptUnknownVisitor, addChildrenTo, addOrderedChildrenTo, buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, calculatePosition, children, findFallBackExpressionFactory, getExpressionFactory, getExpressionRegistry, getGrammar, getIdentifierVersion, getJPAVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, getText, handleAggregate, handleCollection, isAncestor, isIdentifier, isParsingComplete, isTolerant, isUnknown, isVirtual, orderedChildren, parse, parseUsingExpressionFactory, populatePosition, rebuildActualText, rebuildParsedText, setParent, setText, shouldParseWithFactoryFirst, shouldSkipLiteral, toActualText, toParsedText, toString
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Constructor Details
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NullExpression
Creates a newNullExpression
.- Parameters:
parent
- The parent of thisNullExpression
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Method Details
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accept
Description copied from interface:Expression
Visits thisExpression
by the givenvisitor
.- Parameters:
visitor
- TheExpressionVisitor
to visit this object
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acceptChildren
Description copied from interface:Expression
Visits the children of thisExpression
. This method can be used to optimize traversing the children since a new list is not created every timeExpression.children()
is called.This does not traverse the
Expression
sub-hierarchy, use a subclass ofAbstractTraverseChildrenVisitor
in order to traverse the entire sub-hierarchy.- Parameters:
visitor
- Thevisitor
to visit the children of this object.
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findQueryBNF
Description copied from interface:Expression
Retrieves theJPQLQueryBNF
that represents the fragment of thisExpression
that was used when parsing the givenExpression
.- Specified by:
findQueryBNF
in interfaceExpression
- Overrides:
findQueryBNF
in classAbstractExpression
- Parameters:
expression
- TheExpression
that is a descendant of this one- Returns:
- The
JPQLQueryBNF
that was used to parse the given expression
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getQueryBNF
Description copied from interface:Expression
Returns the BNF of thisExpression
.- Returns:
- The
JPQLQueryBNF
, which represents the grammar of thisExpression
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isNull
public boolean isNull()Description copied from class:AbstractExpression
Determines whether this expression is anull
Expression
or any other subclass.- Overrides:
isNull
in classAbstractExpression
- Returns:
false
by default
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parse
Description copied from class:AbstractExpression
Parses the query by starting at the current position, which is part of the givenWordParser
.- Specified by:
parse
in classAbstractExpression
- Parameters:
wordParser
- The text to parse based on the current position of the cursortolerant
- Determines whether the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries
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toParsedText
Description copied from class:AbstractExpression
Generates a string representation of thisExpression
, including its children, if it has any.- Specified by:
toParsedText
in classAbstractExpression
- Parameters:
writer
- The buffer used to append thisExpression
's string representationactual
- 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
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