org.eclipse.persistence.jpa.jpql.parser
Class JPQLQueryBNF

java.lang.Object
  org.eclipse.persistence.jpa.jpql.parser.JPQLQueryBNF

Direct Known Subclasses:

AbstractSchemaNameBNF, AggregateExpressionBNF, AllOrAnyExpressionBNF, ArithmeticExpressionBNF, ArithmeticFactorBNF, ArithmeticPrimaryBNF, ArithmeticTermBNF, BadExpressionBNF, BetweenExpressionBNF, BooleanExpressionBNF, BooleanLiteralBNF, BooleanPrimaryBNF, CaseExpressionBNF, CaseOperandBNF, CastExpressionBNF, CoalesceExpressionBNF, CollectionMemberDeclarationBNF, CollectionMemberExpressionBNF, CollectionValuedPathExpressionBNF, ComparisonExpressionBNF, ConditionalExpressionBNF, ConditionalFactorBNF, ConditionalPrimaryBNF, ConditionalTermBNF, ConstructorExpressionBNF, ConstructorItemBNF, DatabaseTypeQueryBNF, DatetimeExpressionBNF, DateTimePrimaryBNF, DateTimeTimestampLiteralBNF, DeleteClauseBNF, DeleteClauseRangeVariableDeclarationBNF, DeleteStatementBNF, DerivedCollectionMemberDeclarationBNF, ElseExpressionBNF, EmptyCollectionComparisonExpressionBNF, EntityExpressionBNF, EntityOrValueExpressionBNF, EntityTypeExpressionBNF, EntityTypeLiteralBNF, EnumExpressionBNF, EnumLiteralBNF, EnumPrimaryBNF, ExistsExpressionBNF, ExtractExpressionBNF, FromClauseBNF, FunctionExpressionBNF, FunctionItemBNF, FunctionsReturningDatetimeBNF, FunctionsReturningNumericsBNF, FunctionsReturningStringsBNF, GeneralCaseExpressionBNF, GeneralIdentificationVariableBNF, GenericQueryBNF, GroupByClauseBNF, GroupByItemBNF, HavingClauseBNF, IdentificationVariableBNF, IdentificationVariableDeclarationBNF, InExpressionBNF, InExpressionExpressionBNF, InExpressionItemBNF, InputParameterBNF, InternalAggregateFunctionBNF, InternalBetweenExpressionBNF, InternalCoalesceExpressionBNF, InternalColumnExpressionBNF, InternalConcatExpressionBNF, InternalCountBNF, InternalEntityTypeExpressionBNF, InternalFromClauseBNF, InternalJoinBNF, InternalLengthExpressionBNF, InternalLocateStringExpressionBNF, InternalLocateThirdExpressionBNF, InternalLowerExpressionBNF, InternalModExpressionBNF, InternalOrderByClauseBNF, InternalOrderByItemBNF, InternalSelectExpressionBNF, InternalSimpleFromClauseBNF, InternalSimpleSelectExpressionBNF, InternalSqrtExpressionBNF, InternalSubstringPositionExpressionBNF, InternalSubstringStringExpressionBNF, InternalUpdateClauseBNF, InternalUpperExpressionBNF, InternalWhenClauseBNF, JoinAssociationPathExpressionBNF, JoinBNF, JoinFetchBNF, JPQLStatementBNF, LikeExpressionBNF, LikeExpressionEscapeCharacterBNF, LiteralBNF, NewValueBNF, NullComparisonExpressionBNF, NullIfExpressionBNF, NumericLiteralBNF, ObjectExpressionBNF, OnClauseBNF, OrderByClauseBNF, OrderByItemBNF, PatternValueBNF, QualifiedIdentificationVariableBNF, RangeDeclarationBNF, RangeVariableDeclarationBNF, RegexpExpressionBNF, ResultVariableBNF, ScalarExpressionBNF, SelectClauseBNF, SelectExpressionBNF, SelectStatementBNF, SimpleArithmeticExpressionBNF, SimpleCaseExpressionBNF, SimpleConditionalExpressionBNF, SimpleEntityExpressionBNF, SimpleEntityOrValueExpressionBNF, SimpleResultVariableBNF, SimpleSelectClauseBNF, SimpleSelectExpressionBNF, SimpleSelectExpressionBNF2_0, SimpleSelectItemBNF, SingleValuedObjectPathExpressionBNF, SingleValuedPathExpressionBNF, StateFieldPathExpressionBNF, StringExpressionBNF, StringLiteralBNF, StringPrimaryBNF, SubqueryBNF, SubqueryFromClauseBNF, SubSelectIdentificationVariableDeclarationBNF, TableExpressionBNF, TableVariableDeclarationBNF, TreatExpressionBNF, TypeExpressionBNF, UnionClauseBNF, UpdateClauseBNF, UpdateItemBNF, UpdateItemStateFieldPathExpressionBNF, UpdateStatementBNF, VirtualJPQLQueryBNF, WhenClauseBNF, WhereClauseBNF

public abstract class JPQLQueryBNF
extends java.lang.Object

This defines a single Backus-Naur Form (BNF) of the JPQL grammar. The Java Persistence functional specifications are:

JPQLGrammar1_0: JSR 220: Enterprise JavaBeans™ version 3.0
JPQLGrammar2_0: JSR 317: Java™ Persistence 2.0

JPQLGrammar2_1: JSR 338: Java™ Persistence 2.1

Provisional API: This interface is part of an interim API that is still under development and expected to change significantly before reaching stability. It is available at this early stage to solicit feedback from pioneering adopters on the understanding that any code that uses this API will almost certainly be broken (repeatedly) as the API evolves.

Version:

2.4.1

Author:

Pascal Filion

Since:

2.3

Constructor Summary

protected

JPQLQueryBNF(java.lang.String id) Creates a new JPQLQueryBNF.

Method Summary

java.lang.Iterable<JPQLQueryBNF>	children() Returns the set of all the query BNFs that are part of this BNF.
ExpressionFactory	getExpressionFactory(java.lang.String identifier) Retrieves the ExpressionFactory that is associated with the given identifier, if the given string is indeed a JPQL identifier.
java.lang.Iterable<java.lang.String>	getExpressionFactoryIds() Returns the unique identifiers of the ExpressionFactory handled by this BNF rule, which includes those from the children as well.
ExpressionRegistry	getExpressionRegistry() Returns the registry containing the JPQLQueryBNFs and the ExpressionFactories that are used to properly parse a JPQL query.
java.lang.String	getFallbackBNFId() When parsing the query and no JPQLQueryBNFs can help to parse the query, then it will fall back on this one.
java.lang.String	getFallbackExpressionFactoryId() Returns the unique identifier of the ExpressionFactory to use when the fall back BNF ID is not null.
java.lang.String	getId() Returns the unique identifier of this JPQLQueryBNF.
java.lang.Iterable<java.lang.String>	getIdentifiers() Retrieves the JPQL identifiers that are supported by this BNF rule.
boolean	handleAggregate() Determines whether the Expression handles a collection of sub-expressions that are aggregated by logical or arithmetic operators.
boolean	handleCollection() Determines whether the Expression handles a collection of sub-expressions that are separated by commas.
boolean	handlesSubExpression() Determines whether this BNF handles parsing a sub-expression, i.e. parsing an expression encapsulated by parenthesis.
boolean	hasIdentifier(java.lang.String word) Determines if this query BNF support the given word, which can be an identifier.
protected void	initialize() Initializes this BNF by registering child JPQLQueryBNFs and ExpressionFactories.
boolean	isCompound() Determines whether this BNF has child BNFs registered only to properly parse a query or if the child BNFs are part of the BNF.
java.lang.Iterable<JPQLQueryBNF>	nonCompoundChildren() Returns the set of all the query BNFs that are part of this BNF.
protected void	registerChild(java.lang.String queryBNFId) Registers the unique identifier of the BNF rule as a child of this BNF rule.
protected void	registerExpressionFactory(java.lang.String expressionFactoryId) Registers a unique identifier of the ExpressionFactory to register with this BNF rule.
void	setCompound(boolean compound) Determines whether this BNF has child BNFs registered only to properly parse a query or if the child BNFs are part of the BNF.
void	setFallbackBNFId(java.lang.String fallbackBNFId) When parsing the query and no JPQLQueryBNFs can help to parse the query, then it will fall back on the given one.
void	setFallbackExpressionFactoryId(java.lang.String fallbackExpressionFactoryId) Sets the unique identifier of the ExpressionFactory to use when the fall back BNF ID is not null.
void	setHandleAggregate(boolean handleAggregate) Sets whether the Expression handles a collection of sub-expressions that are aggregated by logical or arithmetic operators.
void	setHandleCollection(boolean handleCollection) Sets whether the Expression handles a collection of sub-expressions that are separated by commas.
void	setHandleSubExpression(boolean handleSubExpression) Sets whether this BNF handles parsing a sub-expression, i.e. parsing an expression encapsulated by parenthesis.
java.lang.String	toString()
protected void	toString(java.lang.StringBuilder sb) Adds to the given builder more information about this JPQLQueryBNF.

Methods inherited from class java.lang.Object

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

Constructor Detail

JPQLQueryBNF

protected JPQLQueryBNF(java.lang.String id)

Creates a new JPQLQueryBNF.

Parameters:

id - The unique identifier of this BNF rule

Throws:

java.lang.NullPointerException - The given unique identifier cannot be null

Method Detail

children

public java.lang.Iterable<JPQLQueryBNF> children()

Returns the set of all the query BNFs that are part of this BNF. The set always include this BNF as well.

Returns:

The children BNFs describing this BNF rule

getExpressionFactory

public ExpressionFactory getExpressionFactory(java.lang.String identifier)

Retrieves the ExpressionFactory that is associated with the given identifier, if the given string is indeed a JPQL identifier.

Parameters:

identifier - The JPQL identifier (in theory) that is used to retrieve the factory responsible to parse a portion of the query starting with that identifier

Returns:

The ExpressionFactory responsible to parse a portion of the query starting with the given identifier; null if nothing was registered for it

getExpressionFactoryIds

public java.lang.Iterable<java.lang.String> getExpressionFactoryIds()

Returns the unique identifiers of the ExpressionFactory handled by this BNF rule, which includes those from the children as well.

Returns:

The list of unique identifiers of the ExpressionFactory registered with this BNF rule and with its children

getExpressionRegistry

public ExpressionRegistry getExpressionRegistry()

Returns the registry containing the JPQLQueryBNFs and the ExpressionFactories that are used to properly parse a JPQL query.

Returns:

The registry containing the information related to the JPQL grammar

getFallbackBNFId

public java.lang.String getFallbackBNFId()

When parsing the query and no JPQLQueryBNFs can help to parse the query, then it will fall back on this one.

Returns:

The unique identifier of the JPQLQueryBNF to use in the last resort

getFallbackExpressionFactoryId

public java.lang.String getFallbackExpressionFactoryId()

Returns the unique identifier of the ExpressionFactory to use when the fall back BNF ID is not null. This will be used to parse a portion of the query when the registered expression factories cannot parse it.

Note: This method is only called if getFallbackBNFId() does not return null.

Returns:

The unique identifier of the ExpressionFactory

getId

public java.lang.String getId()

Returns the unique identifier of this JPQLQueryBNF.

Returns:

The identifier used to register this JPQLQueryBNF with AbstractExpression

getIdentifiers

public java.lang.Iterable<java.lang.String> getIdentifiers()

Retrieves the JPQL identifiers that are supported by this BNF rule. The JPQL identifiers are retrieved by scanning the ExpressionFactory registered with this BNF rule and the child BNF rules.

Returns:

The list of JPQL identifiers that are supported by this BNF

handleAggregate

public boolean handleAggregate()

Determines whether the Expression handles a collection of sub-expressions that are aggregated by logical or arithmetic operators.

Returns:

true if the sub-expression to parse might have several logical and/or arithmetic expressions; false otherwise

handleCollection

public boolean handleCollection()

Determines whether the Expression handles a collection of sub-expressions that are separated by commas.

Returns:

true if the sub-expression to parse might have several sub-expressions separated by commas; false otherwise

handlesSubExpression

public boolean handlesSubExpression()

Determines whether this BNF handles parsing a sub-expression, i.e. parsing an expression encapsulated by parenthesis. See setHandleSubExpression(boolean) for more details.

Returns:

true if this BNF handles parsing a sub-expression; false otherwise

hasIdentifier

public boolean hasIdentifier(java.lang.String word)

Determines if this query BNF support the given word, which can be an identifier.

Parameters:

word - A word that could be a JPQL identifier or anything else

Returns:

true if the given word is a JPQL identifier and it is supported by this BNF; false otherwise

initialize

protected void initialize()

Initializes this BNF by registering child JPQLQueryBNFs and ExpressionFactories.

isCompound

public boolean isCompound()

Determines whether this BNF has child BNFs registered only to properly parse a query or if the child BNFs are part of the BNF. An example if a compound BNF is BetweenExpressionBNF, it registers a series of children BNFs but they shouldn't be used to determine if they are part of that BNF since the comparator identifiers are.

Returns:

false by default

nonCompoundChildren

public java.lang.Iterable<JPQLQueryBNF> nonCompoundChildren()

Returns the set of all the query BNFs that are part of this BNF. The set always include this BNF as well.

Returns:

The children BNFs describing this BNF rule. The set excludes BNF rules that are used to complete a BNF, such as the BNF rules defined for BETWEEN since they are required to properly parse the query

registerChild

protected final void registerChild(java.lang.String queryBNFId)

Registers the unique identifier of the BNF rule as a child of this BNF rule.

Parameters:

queryBNFId - The unique identifier of the BNF rule to add as a child

Throws:

java.lang.NullPointerException - The queryBNFId cannot be null

registerExpressionFactory

protected final void registerExpressionFactory(java.lang.String expressionFactoryId)

Registers a unique identifier of the ExpressionFactory to register with this BNF rule.

Parameters:

expressionFactoryId - The unique identifier of the ExpressionFactory

Throws:

java.lang.NullPointerException - The expressionFactoryId cannot be null

setCompound

public void setCompound(boolean compound)

Determines whether this BNF has child BNFs registered only to properly parse a query or if the child BNFs are part of the BNF. An example if a compound BNF is BetweenExpressionBNF, it registers a series of children BNFs but they shouldn't be used to determine if they are part of that BNF since the comparator identifiers are.

Parameters:

compound - true if this BNF represents a compound BNF and its children are not part of this BNF but only to support compound expression; false otherwise

setFallbackBNFId

public void setFallbackBNFId(java.lang.String fallbackBNFId)

When parsing the query and no JPQLQueryBNFs can help to parse the query, then it will fall back on the given one.

Parameters:

fallbackBNFId - The unique identifier of the JPQLQueryBNF to use in the last resort

setFallbackExpressionFactoryId

public void setFallbackExpressionFactoryId(java.lang.String fallbackExpressionFactoryId)

Sets the unique identifier of the ExpressionFactory to use when the fall back BNF ID is not null. This will be used to parse a portion of the query when the registered expression factories cannot parse it.

Note: This method is only called if getFallbackBNFId() does not return null.

Parameters:

fallbackExpressionFactoryId - The unique identifier of the ExpressionFactory

setHandleAggregate

public void setHandleAggregate(boolean handleAggregate)

Sets whether the Expression handles a collection of sub-expressions that are aggregated by logical or arithmetic operators.

Parameters:

handleAggregate - true if the sub-expression to parse might have several logical and/or arithmetic expressions; false otherwise

setHandleCollection

public void setHandleCollection(boolean handleCollection)

Sets whether the Expression handles a collection of sub-expressions that are separated by commas.

Parameters:

handleCollection - true if the sub-expression to parse might have several sub-expressions separated by commas; false otherwise

setHandleSubExpression

public void setHandleSubExpression(boolean handleSubExpression)

Sets whether this BNF handles parsing a sub-expression, i.e. parsing an expression encapsulated by parenthesis. Which in fact would be handled by the fallback ExpressionFactory. The default behavior is to not handle it.

A good example for using this option is when an Expression cannot use any ExpressionFactory for creating a child object, parsing will use the fallback ExpressionFactory, if one was specified. So when this is set to true, the fallback ExpressionFactory will be immediately invoked.

Let's say we want to parse "SELECT e FROM (SELECT a FROM Address a) e", FromClause cannot use a factory for parsing the entity name (that's what usually the FROM clause has) so it uses the fallback factory to create IdentificationVariableDeclaration. Then IdentificationVariableDeclaration also cannot use any factory to create its child object so it uses the fallback factory to create RangeVariableDeclaration. By changing the status of for handling the sub-expression for the BNFs for those objects, then a subquery can be created by RangeVariableDeclaration.

FromClause
  |- IdentificationVariableDeclaration
       |- RangeVariableDeclaration
            |- SubExpression(subquery)

In order to get this working, the following would have to be done into the grammar:

 public class MyJPQLGrammar extends AbstractJPQLGrammar {
   @Override
   protected void initializeBNFs() {
      setHandleSubExpression(InternalFromClauseBNF.ID,                true);
      setHandleSubExpression(InternalSimpleFromClauseBNF.ID,          true);
      setHandleSubExpression(IdentificationVariableDeclarationBNF.ID, true);
      setHandleSubExpression(RangeVariableDeclarationBNF.ID,          true);
   }
 }

Parameters:

handleSubExpression - true to let the creation of a sub-expression be created by the fallback ExpressionFactory registered with this BNF; false otherwise (which is the default value)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toString

protected void toString(java.lang.StringBuilder sb)

Adds to the given builder more information about this JPQLQueryBNF.

Parameters:

sb - The builder used to add information about this class