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Oracle Fusion Middleware Java API Reference for Oracle TopLink 11g Release 1 (11.1.1) E28847-01 |
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java.lang.Object
org.eclipse.persistence.jpa.internal.jpql.parser.StringExpression
org.eclipse.persistence.jpa.internal.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.internal.jpql.parser.IdentificationVariable
public final class IdentificationVariable
An identification variable is a valid identifier declared in the FROM clause of a query.
Requirements:
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:
The identification variable declarations are evaluated from left to right in the FROM clause, and an identification variable declaration can use the result of a preceding identification variable declaration of the query string.
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.
Field Summary | |
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private StateFieldPathExpression |
stateFieldPathExpression The virtual state field path expression having |
private boolean |
virtual Determines whether this identification variable is virtual, meaning it's not part of the query but is required for proper navigability. |
Fields inherited from class org.eclipse.persistence.jpa.internal.jpql.parser.AbstractExpression |
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COMMA, DOT, DOUBLE_QUOTE, LEFT_CURLY_BRACKET, LEFT_PARENTHESIS, NOT_DEFINED, RIGHT_CURLY_BRACKET, RIGHT_PARENTHESIS, SINGLE_QUOTE, SPACE, UNDERSCORE |
Constructor Summary | |
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IdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable) Creates a new IdentificationVariable . |
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IdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable, boolean virtual) Creates a new IdentificationVariable . |
Method Summary | |
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void |
accept(ExpressionVisitor visitor) Visits this Expression by the given visitor . |
void |
acceptChildren(ExpressionVisitor visitor) Visits the children of this Expression . |
(package private) void |
addOrderedChildrenTo(java.util.List<StringExpression> children) Adds the StringExpressions representing this Expression . |
JPQLQueryBNF |
getQueryBNF() Returns the BNF of this Expression . |
StateFieldPathExpression |
getStateFieldPathExpression() Returns the actual representation of the parsed information. |
java.lang.String |
getText() Returns the encapsulated text of this AbstractExpression , which can be used in various ways, it can be a keyword, a literal, etc. |
boolean |
isVirtual() Determines whether this identification variable is virtual, meaning it's not part of the query but is required for proper navigability. |
(package private) void |
parse(WordParser wordParser, boolean tolerant) Parses the query by starting at the current position, which is part of the given WordParser . |
(package private) void |
setVirtualIdentificationVariable(java.lang.String variableName) Sets a virtual identification variable because the abstract schema name was parsed without one. |
java.lang.String |
toParsedText() Returns a string representation of this StringExpression and its children. |
(package private) void |
toParsedText(java.lang.StringBuilder writer, boolean includeVirtual) Generates a string representation of this Expression . |
Methods inherited from class org.eclipse.persistence.jpa.internal.jpql.parser.AbstractExpression |
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addChildrenTo, buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, children, expressionFactory, expressionFactoryForIdentifier, findQueryBNF, getChildren, getJPAVersion, getParent, getRoot, handleAggregate, identifierRole, identifiers, identifiers, identifierVersion, isAncestor, isIdentifier, isNull, isParsingComplete, isTolerant, isUnknown, orderedChildren, parse, parseSingleExpression, populatePosition, queryBNF, readdLeadingSpaces, rebuildActualText, rebuildParsedText, setParent, setText, shouldParseWithFactoryFirst, shouldSkipLiteral, toActualText, toString |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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private StateFieldPathExpression stateFieldPathExpression
private boolean virtual
Constructor Detail |
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IdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable)
IdentificationVariable
.
parent
- The parent of this expressionidentificationVariable
- The actual identification variableIdentificationVariable(AbstractExpression parent, java.lang.String identificationVariable, boolean virtual)
IdentificationVariable
.
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 navigabilityMethod Detail |
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public void accept(ExpressionVisitor visitor)
Expression
by the given visitor
.visitor
- The visitor
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()
or Expression.getChildren()
is called.
This does not traverse the Expression
sub-hierarchy, use an subclass of AbstractTraverseChildrenVisitor
in order to traverse the entire sub-hierarchy.
visitor
- The visitor
to visit the children of this object.void addOrderedChildrenTo(java.util.List<StringExpression> children)
StringExpressions
representing this Expression
.addOrderedChildrenTo
in class AbstractExpression
children
- The list used to store the string representation of this Expression
public JPQLQueryBNF getQueryBNF()
Expression
.getQueryBNF
in class AbstractExpression
JPQLQueryBNF
, which represents the grammar of this Expression
public StateFieldPathExpression getStateFieldPathExpression()
isVirtual()
returns true
. This is valid in an UPDATE and DELETE queries where the identification variable is not specified.java.lang.IllegalAccessError
- If this expression does not have a virtual identification variablepublic java.lang.String getText()
AbstractExpression
, which can be used in various ways, it can be a keyword, a literal, etc.getText
in class AbstractExpression
public boolean isVirtual()
isVirtual
in class AbstractExpression
true
if this identification variable was virtually created to fully qualify path expression; false
if it was parsedvoid parse(WordParser wordParser, boolean tolerant)
WordParser
.parse
in class AbstractExpression
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 queriesvoid setVirtualIdentificationVariable(java.lang.String variableName)
variableName
- The identification variable that was generated to identify the abstract schema namepublic java.lang.String toParsedText()
StringExpression
and its children. The expression should contain whitespace even if the beautified version would not have any. For instance, "SELECT e " should be returned where Expression#toText()
would return "SELECT e".toParsedText
in interface Expression
toParsedText
in class AbstractExpression
StringExpression
void toParsedText(java.lang.StringBuilder writer, boolean includeVirtual)
Expression
.toParsedText
in class AbstractExpression
writer
- The buffer used to append this Expression
's string representationincludeVirtual
- Determines whether to include any characters that are considered virtual, i.e. that was parsed when the query is incomplete and is needed for functionality like content assist
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