Class NullExpression
- java.lang.Object
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- org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
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- org.eclipse.persistence.jpa.jpql.parser.NullExpression
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- All Implemented Interfaces:
Expression
public final class NullExpression extends AbstractExpression
AnullExpressionis used instead of a truenull, which allows operations to be performed without doing anullcheck first.- Version:
- 2.5
- Author:
- Pascal Filion
- Since:
- 2.3
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Field Summary
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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
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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
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Constructor Summary
Constructors Constructor Description NullExpression(AbstractExpression parent)Creates a newNullExpression.
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description voidaccept(ExpressionVisitor visitor)Visits thisExpressionby the givenvisitor.voidacceptChildren(ExpressionVisitor visitor)Visits the children of thisExpression.JPQLQueryBNFfindQueryBNF(Expression expression)Retrieves theJPQLQueryBNFthat represents the fragment of thisExpressionthat was used when parsing the givenExpression.JPQLQueryBNFgetQueryBNF()Returns the BNF of thisExpression.booleanisNull()Determines whether this expression is anullExpressionor any other subclass.protected voidparse(WordParser wordParser, boolean tolerant)Parses the query by starting at the current position, which is part of the givenWordParser.protected voidtoParsedText(java.lang.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 Detail
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NullExpression
public NullExpression(AbstractExpression parent)
Creates a newNullExpression.- Parameters:
parent- The parent of thisNullExpression
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Method Detail
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accept
public void accept(ExpressionVisitor visitor)
Visits thisExpressionby the givenvisitor.- Parameters:
visitor- TheExpressionVisitorto visit this object
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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
Expressionsub-hierarchy, use a subclass ofAbstractTraverseChildrenVisitorin order to traverse the entire sub-hierarchy.- Parameters:
visitor- Thevisitorto visit the children of this object.
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findQueryBNF
public JPQLQueryBNF findQueryBNF(Expression expression)
Retrieves theJPQLQueryBNFthat represents the fragment of thisExpressionthat was used when parsing the givenExpression.- Specified by:
findQueryBNFin interfaceExpression- Overrides:
findQueryBNFin classAbstractExpression- Parameters:
expression- TheExpressionthat is a descendant of this one- Returns:
- The
JPQLQueryBNFthat was used to parse the given expression
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getQueryBNF
public JPQLQueryBNF getQueryBNF()
Returns the BNF of thisExpression.- Returns:
- The
JPQLQueryBNF, which represents the grammar of thisExpression
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isNull
public boolean isNull()
Determines whether this expression is anullExpressionor any other subclass.- Overrides:
isNullin classAbstractExpression- Returns:
falseby default
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parse
protected void parse(WordParser wordParser, boolean tolerant)
Parses the query by starting at the current position, which is part of the givenWordParser.- Specified by:
parsein 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
protected void toParsedText(java.lang.StringBuilder writer, boolean actual)Generates a string representation of thisExpression, including its children, if it has any.- Specified by:
toParsedTextin 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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