public final class NullExpression extends AbstractExpression
null Expression is used instead of a true null, which allows
operations to be performed without doing a null check first.COMMA, DOT, DOUBLE_QUOTE, LEFT_CURLY_BRACKET, LEFT_PARENTHESIS, NOT_DEFINED, RIGHT_CURLY_BRACKET, RIGHT_PARENTHESIS, SINGLE_QUOTE, SPACE, UNDERSCOREABS, 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 and Description |
|---|
NullExpression(AbstractExpression parent)
Creates a new
NullExpression. |
| 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. |
JPQLQueryBNF |
findQueryBNF(Expression expression)
Retrieves the
JPQLQueryBNF that represents the fragment of this Expression
that was used when parsing the given Expression. |
JPQLQueryBNF |
getQueryBNF()
Returns the BNF of this
Expression. |
boolean |
isNull()
Determines whether this expression is a
null 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 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. |
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, toStringpublic NullExpression(AbstractExpression parent)
NullExpression.parent - The parent of this NullExpressionpublic void accept(ExpressionVisitor visitor)
Expression by the given visitor.visitor - The ExpressionVisitor to visit this objectpublic void acceptChildren(ExpressionVisitor visitor)
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.
visitor - The visitor to visit the children of this object.public JPQLQueryBNF findQueryBNF(Expression expression)
JPQLQueryBNF that represents the fragment of this Expression
that was used when parsing the given Expression.findQueryBNF in interface ExpressionfindQueryBNF in class AbstractExpressionexpression - The Expression that is a descendant of this oneJPQLQueryBNF that was used to parse the given expressionpublic JPQLQueryBNF getQueryBNF()
Expression.JPQLQueryBNF, which represents the grammar of this Expressionpublic boolean isNull()
null Expression or any other subclass.isNull in class AbstractExpressionfalse by defaultprotected void parse(WordParser wordParser, boolean tolerant)
WordParser.parse in class AbstractExpressionwordParser - 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 queriesprotected void toParsedText(java.lang.StringBuilder writer,
boolean actual)
Expression, including its children,
if it has any.toParsedText in class AbstractExpressionwriter - The buffer used to append this Expression'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