Class NullExpression
- java.lang.Object
-
- org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
-
- org.eclipse.persistence.jpa.jpql.parser.NullExpression
-
- All Implemented Interfaces:
Expression
public final class NullExpression extends AbstractExpression
Anull
Expression
is used instead of a truenull
, which allows operations to be performed without doing anull
check first.- Since:
- 2.3
- Version:
- 2.5
- Author:
- Pascal Filion
-
-
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, 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 Summary
Constructors Constructor Description NullExpression(AbstractExpression parent)
Creates a newNullExpression
.
-
Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description void
accept(ExpressionVisitor visitor)
Visits thisExpression
by the givenvisitor
.void
acceptChildren(ExpressionVisitor visitor)
Visits the children of thisExpression
.JPQLQueryBNF
findQueryBNF(Expression expression)
Retrieves theJPQLQueryBNF
that represents the fragment of thisExpression
that was used when parsing the givenExpression
.JPQLQueryBNF
getQueryBNF()
Returns the BNF of thisExpression
.boolean
isNull()
-
Methods inherited from class org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
children, getGrammar, getIdentifierVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, isAncestor, orderedChildren, populatePosition, toActualText, toParsedText, toString
-
-
-
-
Constructor Detail
-
NullExpression
public NullExpression(AbstractExpression parent)
Creates a newNullExpression
.- Parameters:
parent
- The parent of thisNullExpression
-
-
Method Detail
-
accept
public void accept(ExpressionVisitor visitor)
Visits thisExpression
by the givenvisitor
.- Parameters:
visitor
- TheExpressionVisitor
to visit this object
-
acceptChildren
public void acceptChildren(ExpressionVisitor visitor)
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.
-
findQueryBNF
public JPQLQueryBNF findQueryBNF(Expression 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
-
getQueryBNF
public JPQLQueryBNF getQueryBNF()
Returns the BNF of thisExpression
.- Returns:
- The
JPQLQueryBNF
, which represents the grammar of thisExpression
-
isNull
public boolean isNull()
-
-