org.eclipse.persistence.internal.jpa.jpql

Class JPQLQueryHelper

java.lang.Object

org.eclipse.persistence.internal.jpa.jpql.JPQLQueryHelper

public class JPQLQueryHelper
extends java.lang.Object

This helper can perform various operations over a JPQL query.

Since:

2.5

Version:

2.5

Author:

Pascal Filion

Constructor Summary

Constructors

Constructor and Description
JPQLQueryHelper() Creates a new JPQLQueryHelper which uses the latest JPQL grammar.
JPQLQueryHelper(JPQLGrammar jpqlGrammar) Creates a new JPQLQueryHelper.

Method Summary

Modifier and Type	Method and Description
java.util.List<ClassDescriptor>	getClassDescriptors(java.lang.CharSequence jpqlQuery, AbstractSession session) Retrieves the list of descriptors corresponding to the entities used throughout the given JPQL query.
java.util.List<ConstructorQueryMappings>	getConstructorQueryMappings(AbstractSession session) Retrieves the class names and the attribute names mapped to their types that are used in the constructor expressions defined in the SELECT clause.
ConstructorQueryMappings	getConstructorQueryMappings(AbstractSession session, DatabaseQuery query) Retrieves the class names and the attribute names mapped to their types that are used in the constructor expressions defined in the SELECT clause.
JPQLGrammar	getGrammar() Returns the JPQL grammar that will be used to define how to parse a JPQL query.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

JPQLQueryHelper

public JPQLQueryHelper()

Creates a new JPQLQueryHelper which uses the latest JPQL grammar.

JPQLQueryHelper

public JPQLQueryHelper(JPQLGrammar jpqlGrammar)

Creates a new JPQLQueryHelper.

Parameters:

jpqlGrammar - The JPQLGrammar that will determine how to parse JPQL queries

Throws:

java.lang.NullPointerException - The JPQLGrammar cannot be null

Method Detail

getClassDescriptors

public java.util.List<ClassDescriptor> getClassDescriptors(java.lang.CharSequence jpqlQuery,
                                                           AbstractSession session)

Retrieves the list of descriptors corresponding to the entities used throughout the given JPQL query.

Parameters:

jpqlQuery - The JPQL query used to gather the descriptors defined in the declaration clause

session - The AbstractSession is used to retrieve the descriptors

Returns:

The list of descriptors used in the JPQL query or an empty list if the JPQL query is invalid or incomplete

getConstructorQueryMappings

public java.util.List<ConstructorQueryMappings> getConstructorQueryMappings(AbstractSession session)

Retrieves the class names and the attribute names mapped to their types that are used in the constructor expressions defined in the SELECT clause.

For instance, from the following JPQL query:

 SELECT new test.example.Employee(e.name, e.id),
        new test.example.Address(a.zipcode)
 FROM Employee e, Address a

The return object is

 |- test.example.Employee
 |-   |- name : String
 |-   |- id : int
 |- test.example.Address
      |- zipcode : int

Parameters:

session - The AbstractSession is used to retrieve the mappings used in the constructor items

Returns:

The holder of the result

getConstructorQueryMappings

public ConstructorQueryMappings getConstructorQueryMappings(AbstractSession session,
                                                            DatabaseQuery query)

Retrieves the class names and the attribute names mapped to their types that are used in the constructor expressions defined in the SELECT clause.

For instance, from the following JPQL query:

 SELECT new test.example.Address(a.streetName, a.zipcode)
 FROM Address a

The return object is

 test.example.Address
    |- BasicMapping(streetName) : String
    |- BasicMapping(zipcode) : int

Parameters:

session - The AbstractSession is used to retrieve the mappings used in the constructor items

Returns:

The holder of the result

getGrammar

public JPQLGrammar getGrammar()

Returns the JPQL grammar that will be used to define how to parse a JPQL query.

Returns:

The grammar that will determine how to parse a JPQL query