org.eclipse.persistence.jpa.jpql.parser

Class HierarchicalQueryClause

java.lang.Object

org.eclipse.persistence.jpa.jpql.parser.AbstractExpression

org.eclipse.persistence.jpa.jpql.parser.HierarchicalQueryClause

All Implemented Interfaces:

Expression

public final class HierarchicalQueryClause
extends AbstractExpression

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]

Version:

2.5

See Also:

StartWithClause, ConnectByClause, OrderSiblingsByClause

Author:

Pascal Filion

Since:

2.5

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 and Description
HierarchicalQueryClause(AbstractExpression parent) Creates a new HierarchicalQueryClause.

Method Summary

Modifier and Type	Method and Description
void	accept(ExpressionVisitor visitor) Visits this Expression by the given visitor.
void	acceptChildren(ExpressionVisitor visitor) Visits the children of this Expression.
protected void	addChildrenTo(java.util.Collection<Expression> children) Adds the children of this AbstractExpression to the given collection.
protected void	addOrderedChildrenTo(java.util.List<Expression> children) Adds the children of this AbstractExpression to the given list.
JPQLQueryBNF	findQueryBNF(Expression expression) Retrieves the JPQLQueryBNF that represents the fragment of this Expression that was used when parsing the given Expression.
Expression	getConnectByClause() Returns the Expression representing the CONNECT BY clause.
Expression	getOrderSiblingsByClause() Returns the Expression representing the ORDER SIBLINGS BY clause.
JPQLQueryBNF	getQueryBNF() Returns the BNF of this Expression.
Expression	getStartWithClause() Returns the Expression representing the START WITH clause.
boolean	hasConnectByClause() Determines whether the CONNECT BY clause is defined.
boolean	hasOrderSiblingsByClause() Determines whether the ORDER SIBLINGS BY clause is defined.
boolean	hasSpaceAfterConnectByClause() Determines whether a whitespace was found after the CONNECT BY clause.
boolean	hasSpaceAfterStartWithClause() Determines whether a whitespace was found after the START WITH clause.
boolean	hasStartWithClause() 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 given WordParser.
protected void	toParsedText(java.lang.StringBuilder writer, boolean actual) Generates a string representation of this Expression, 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

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

HierarchicalQueryClause

public HierarchicalQueryClause(AbstractExpression parent)

Creates a new HierarchicalQueryClause.

Parameters:

parent - The parent of this expression

Method Detail

accept

public void accept(ExpressionVisitor visitor)

Visits this Expression by the given visitor.

Parameters:

visitor - The ExpressionVisitor to visit this object

acceptChildren

public void acceptChildren(ExpressionVisitor visitor)

Visits the children of this Expression. This method can be used to optimize traversing the children since a new list is not created every time Expression.children() is called.

This does not traverse the Expression sub-hierarchy, use a subclass of AbstractTraverseChildrenVisitor in order to traverse the entire sub-hierarchy.

Parameters:

visitor - The visitor to visit the children of this object.

addChildrenTo

protected void addChildrenTo(java.util.Collection<Expression> children)

Adds the children of this AbstractExpression to the given collection.

Overrides:

addChildrenTo in class AbstractExpression

Parameters:

children - The collection used to store the children

addOrderedChildrenTo

protected void addOrderedChildrenTo(java.util.List<Expression> children)

Adds the children of this AbstractExpression to the given list.

Overrides:

addOrderedChildrenTo in class AbstractExpression

Parameters:

children - The list used to store the string representation of this AbstractExpression

findQueryBNF

public JPQLQueryBNF findQueryBNF(Expression expression)

Retrieves the JPQLQueryBNF that represents the fragment of this Expression that was used when parsing the given Expression.

Specified by:

findQueryBNF in interface Expression

Overrides:

findQueryBNF in class AbstractExpression

Parameters:

expression - The Expression that is a descendant of this one

Returns:

The JPQLQueryBNF that was used to parse the given expression

getConnectByClause

public Expression getConnectByClause()

Returns the Expression representing the CONNECT BY clause.

Returns:

The expression representing the CONNECT BY clause

getOrderSiblingsByClause

public Expression getOrderSiblingsByClause()

Returns the Expression representing the ORDER SIBLINGS BY clause.

Returns:

The expression representing the ORDER SIBLINGS BY clause

getQueryBNF

public JPQLQueryBNF getQueryBNF()

Returns the BNF of this Expression.

Returns:

The JPQLQueryBNF, which represents the grammar of this Expression

getStartWithClause

public Expression getStartWithClause()

Returns the Expression representing the START WITH clause.

Returns:

The expression representing the START WITH clause

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

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

hasSpaceAfterConnectByClause

public boolean hasSpaceAfterConnectByClause()

Determines whether a whitespace was found after the CONNECT 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 the CONNECT BY clause and owned by this expression; false otherwise

hasSpaceAfterStartWithClause

public boolean hasSpaceAfterStartWithClause()

Determines whether a whitespace was found after the START 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 the START WITH clause and owned by this expression; false otherwise

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

parse

protected void parse(WordParser wordParser,
                     boolean tolerant)

Parses the query by starting at the current position, which is part of the given WordParser.

Specified by:

parse in class AbstractExpression

Parameters:

wordParser - The text to parse based on the current position of the cursor

tolerant - Determines whether the parsing system should be tolerant, meaning if it should try to parse invalid or incomplete queries

toParsedText

protected void toParsedText(java.lang.StringBuilder writer,
                            boolean actual)

Generates a string representation of this Expression, including its children, if it has any.

Specified by:

toParsedText in class AbstractExpression

Parameters:

writer - The buffer used to append this Expression's string representation

actual - 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