Class HierarchicalQueryClause
java.lang.Object
org.eclipse.persistence.jpa.jpql.parser.AbstractExpression
org.eclipse.persistence.jpa.jpql.parser.HierarchicalQueryClause
- All Implemented Interfaces:
Expression
If a table contains hierarchical data, then rows can be selected in a hierarchical order using
the hierarchical query clause.
START WITH
specifies the root row(s) of the hierarchy.
CONNECT BY
specifies the relationship between parent rows and child rows of
the hierarchy.
BNF:
hierarchical_query_clause ::= [start_with_clause] connectby_clause [order_siblings_by_clause]
- Since:
- 2.5
- Version:
- 2.5
- See Also:
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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, CEILING, CHAR_LENGTH, CHARACTER_LENGTH, CLASS, COALESCE, COLUMN, CONCAT, CONNECT_BY, COUNT, CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, DATE, DATETIME, DELETE, DELETE_FROM, DESC, DIFFERENT, DISTINCT, DIVISION, ELSE, EMPTY, END, ENTRY, EQUAL, ESCAPE, EXCEPT, EXISTS, EXP, EXTRACT, FALSE, FETCH, FIRST, FLOOR, 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, LN, LOCAL, 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, POWER, QUOTE, REGEXP, ROUND, SCN, SELECT, SET, SIGN, SIZE, SOME, SQL, SQRT, START_WITH, SUBSTRING, SUM, TABLE, THEN, TIME, TIMESTAMP, TRAILING, TREAT, TRIM, TRUE, TYPE, UNION, UNKNOWN, UPDATE, UPPER, VALUE, WHEN, WHERE
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Constructor Summary
ConstructorDescriptionCreates a newHierarchicalQueryClause
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Method Summary
Modifier and TypeMethodDescriptionvoid
accept
(ExpressionVisitor visitor) Visits thisExpression
by the givenvisitor
.void
acceptChildren
(ExpressionVisitor visitor) Visits the children of thisExpression
.protected void
addChildrenTo
(Collection<Expression> children) Adds the children of thisAbstractExpression
to the given collection.protected void
addOrderedChildrenTo
(List<Expression> children) Adds the children of thisAbstractExpression
to the given list.findQueryBNF
(Expression expression) Retrieves theJPQLQueryBNF
that represents the fragment of thisExpression
that was used when parsing the givenExpression
.Returns theExpression
representing the CONNECT BY clause.Returns theExpression
representing the ORDER SIBLINGS BY clause.Returns the BNF of thisExpression
.Returns theExpression
representing the START WITH clause.boolean
Determines whether the CONNECT BY clause is defined.boolean
Determines whether the ORDER SIBLINGS BY clause is defined.boolean
Determines whether a whitespace was found after theCONNECT BY
clause.boolean
Determines whether a whitespace was found after theSTART WITH
clause.boolean
Determines whether the START WITH clause is defined.protected void
parse
(WordParser wordParser, boolean tolerant) Parses the query by starting at the current position, which is part of the givenWordParser
.protected void
toParsedText
(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, buildExpressionFromFallingBack, buildNullExpression, buildStringExpression, buildStringExpression, buildUnknownExpression, calculatePosition, children, findFallBackExpressionFactory, getExpressionFactory, getExpressionRegistry, getGrammar, getIdentifierVersion, getJPAVersion, getLength, getOffset, getParent, getQueryBNF, getRoot, getText, handleAggregate, handleCollection, isAncestor, isIdentifier, isNull, isParsingComplete, isTolerant, isUnknown, isVirtual, orderedChildren, parse, parseUsingExpressionFactory, populatePosition, rebuildActualText, rebuildParsedText, setParent, setText, shouldParseWithFactoryFirst, shouldSkipLiteral, toActualText, toParsedText, toString
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Constructor Details
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HierarchicalQueryClause
Creates a newHierarchicalQueryClause
.- Parameters:
parent
- The parent of this expression
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Method Details
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accept
Description copied from interface:Expression
Visits thisExpression
by the givenvisitor
.- Parameters:
visitor
- TheExpressionVisitor
to visit this object
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acceptChildren
Description copied from interface:Expression
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.
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addChildrenTo
Description copied from class:AbstractExpression
Adds the children of thisAbstractExpression
to the given collection.- Overrides:
addChildrenTo
in classAbstractExpression
- Parameters:
children
- The collection used to store the children
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addOrderedChildrenTo
Description copied from class:AbstractExpression
Adds the children of thisAbstractExpression
to the given list.- Overrides:
addOrderedChildrenTo
in classAbstractExpression
- Parameters:
children
- The list used to store the string representation of thisAbstractExpression
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findQueryBNF
Description copied from interface: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
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getConnectByClause
Returns theExpression
representing the CONNECT BY clause.- Returns:
- The expression representing the CONNECT BY clause
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getOrderSiblingsByClause
Returns theExpression
representing the ORDER SIBLINGS BY clause.- Returns:
- The expression representing the ORDER SIBLINGS BY clause
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getQueryBNF
Description copied from interface:Expression
Returns the BNF of thisExpression
.- Returns:
- The
JPQLQueryBNF
, which represents the grammar of thisExpression
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getStartWithClause
Returns theExpression
representing the START WITH clause.- Returns:
- The expression representing the START WITH clause
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hasConnectByClause
public boolean hasConnectByClause()Determines whether the CONNECT BY clause is defined.- Returns:
true
if the query that got parsed had the CONNECT BY clause
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hasOrderSiblingsByClause
public boolean hasOrderSiblingsByClause()Determines whether the ORDER SIBLINGS BY clause is defined.- Returns:
true
if the query that got parsed had the ORDER SIBLINGS BY clause
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hasSpaceAfterConnectByClause
public boolean hasSpaceAfterConnectByClause()Determines whether a whitespace was found after theCONNECT BY
clause. In some cases, the space is owned by a child of the hierarchical query clause.- Returns:
true
if there was a whitespace after theCONNECT BY
clause and owned by this expression;false
otherwise
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hasSpaceAfterStartWithClause
public boolean hasSpaceAfterStartWithClause()Determines whether a whitespace was found after theSTART WITH
clause. In some cases, the space is owned by a child of the hierarchical query clause.- Returns:
true
if there was a whitespace after theSTART WITH
clause and owned by this expression;false
otherwise
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hasStartWithClause
public boolean hasStartWithClause()Determines whether the START WITH clause is defined.- Returns:
true
if the query that got parsed had the START WITH clause
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parse
Description copied from class:AbstractExpression
Parses the query by starting at the current position, which is part of the givenWordParser
.- Specified by:
parse
in 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
Description copied from class:AbstractExpression
Generates a string representation of thisExpression
, including its children, if it has any.- Specified by:
toParsedText
in 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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