Class IdentificationVariable
- java.lang.Object
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- org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
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- org.eclipse.persistence.jpa.jpql.parser.IdentificationVariable
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- All Implemented Interfaces:
Expression
public final class IdentificationVariable extends AbstractExpression
An identification variable is a valid identifier declared in the FROM clause of a query.Requirements:
- All identification variables must be declared in the FROM clause. Identification variables cannot be declared in other clauses.
- An identification variable must not be a reserved identifier or have the same name as any entity in the same persistence unit.
- Identification variables are case insensitive.
- An identification variable evaluates to a value of the type of the expression used in declaring the variable.
An identification variable can range over an entity, embeddable, or basic abstract schema type. An identification variable designates an instance of an abstract schema type or an element of a collection of abstract schema type instances.
Note that for identification variables referring to an instance of an association or collection represented as a
Map, the identification variable is of the abstract schema type of the map value.An identification variable always designates a reference to a single value. It is declared in one of three ways:
- In a range variable declaration;
- In a join clause;
- In a collection member declaration.
All identification variables used in the SELECT, WHERE, ORDER BY, GROUP BY, or HAVING clause of a SELECT or DELETE statement must be declared in the FROM clause. The identification variables used in the WHERE clause of an UPDATE statement must be declared in the UPDATE clause.
An identification variable is scoped to the query (or subquery) in which it is defined and is also visible to any subqueries within that query scope that do not define an identification variable of the same name.
- Version:
- 2.4
- 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 IdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable)Creates a newIdentificationVariable.IdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable, boolean virtual)Creates a newIdentificationVariable.
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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.protected voidaddOrderedChildrenTo(java.util.List<Expression> children)Adds the children of thisAbstractExpressionto the given list.JPQLQueryBNFgetQueryBNF()Returns the BNF of thisExpression.StateFieldPathExpressiongetStateFieldPathExpression()Returns the actual representation of the parsed information.java.lang.StringgetText()Returns the encapsulated text of thisAbstractExpression, which can be used in various ways, it can be a keyword, a literal, etc.java.lang.StringgetVariableName()Returns the identification variable, which has been changed to be upper case.booleanisVirtual()Determines whether thisAbstractExpressionis virtual, meaning it's not part of the query but is required for proper navigability.protected voidparse(WordParser wordParser, boolean tolerant)Parses the query by starting at the current position, which is part of the givenWordParser.voidsetVirtualIdentificationVariable(java.lang.String variableName)Sets a virtual identification variable because the abstract schema name was parsed without one.java.lang.StringtoParsedText()Returns a string representation of thisExpressionand its children.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, buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, calculatePosition, children, findFallBackExpressionFactory, findQueryBNF, getExpressionFactory, getExpressionRegistry, getGrammar, getIdentifierVersion, getJPAVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, handleAggregate, handleCollection, isAncestor, isIdentifier, isNull, isParsingComplete, isTolerant, isUnknown, orderedChildren, parse, parseUsingExpressionFactory, populatePosition, rebuildActualText, rebuildParsedText, setParent, setText, shouldParseWithFactoryFirst, shouldSkipLiteral, toActualText, toString
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Constructor Detail
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IdentificationVariable
public IdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable)
Creates a newIdentificationVariable.- Parameters:
parent- The parent of this expressionidentificationVariable- The actual identification variable
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IdentificationVariable
public IdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable, boolean virtual)
Creates a newIdentificationVariable.- Parameters:
parent- The parent of this expressionidentificationVariable- The actual identification variablevirtual- Determines whether this identification variable is virtual, meaning it's not part of the query but is required for proper navigability
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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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addOrderedChildrenTo
protected void addOrderedChildrenTo(java.util.List<Expression> children)
Adds the children of thisAbstractExpressionto the given list.- Overrides:
addOrderedChildrenToin classAbstractExpression- Parameters:
children- The list used to store the string representation of thisAbstractExpression
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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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getStateFieldPathExpression
public StateFieldPathExpression getStateFieldPathExpression()
Returns the actual representation of the parsed information. This method should only be called ifisVirtual()returnstrue. This is valid in an UPDATE and DELETE queries where the identification variable is not specified.- Returns:
- The path expression that is qualified by the virtual identification variable
- Throws:
java.lang.IllegalAccessError- If this expression does not have a virtual identification variable
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getText
public java.lang.String getText()
Returns the encapsulated text of thisAbstractExpression, which can be used in various ways, it can be a keyword, a literal, etc.- Overrides:
getTextin classAbstractExpression- Returns:
- Either the JPQL identifier for this
AbstractExpression, the literal it encapsulates or an empty string
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getVariableName
public java.lang.String getVariableName()
Returns the identification variable, which has been changed to be upper case.- Returns:
- The uppercase version of the identification variable
- Since:
- 2.4
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isVirtual
public boolean isVirtual()
Determines whether thisAbstractExpressionis virtual, meaning it's not part of the query but is required for proper navigability.- Overrides:
isVirtualin classAbstractExpression- Returns:
trueif thisAbstractExpressionwas virtually created to fully qualify path expression;falseif it was parsed
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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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setVirtualIdentificationVariable
public void setVirtualIdentificationVariable(java.lang.String variableName)
Sets a virtual identification variable because the abstract schema name was parsed without one. This is valid in an UPDATE and DELETE queries. This internally transforms the what was thought to be an identification variable to a path expression.- Parameters:
variableName- The identification variable that was generated to identify the "root" object
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toParsedText
public java.lang.String toParsedText()
Returns a string representation of thisExpressionand its children. The expression should contain whitespace even if the beautified version would not have any. For instance, "SELECT e " should be returned whereExpression.toParsedText()would return "SELECT e".- Specified by:
toParsedTextin interfaceExpression- Overrides:
toParsedTextin classAbstractExpression- Returns:
- The string representation of this
Expression
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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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