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. |
children, getGrammar, getIdentifierVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, isAncestor, orderedChildren, populatePosition, 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.false by defaultEclipseLink 2.6.3, "build v20160428-59c81c5" API Reference