org.jbpm.query.jpa.impl

Class QueryCriteriaUtil

java.lang.Object

org.jbpm.query.jpa.impl.QueryCriteriaUtil

public abstract class QueryCriteriaUtil
extends Object

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	QueryCriteriaUtil()
	QueryCriteriaUtil(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes)

Method Summary

Modifier and Type	Method and Description
static void	addCriteria(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes, String listId, javax.persistence.metamodel.Attribute attr)
static void	addCriteria(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes, String listId, Class table, javax.persistence.metamodel.Attribute attr)
static void	applyMetaCriteriaToQuery(javax.persistence.Query query, QueryWhere queryWhere) Small method to apply the meta criteria from the QueryWhere instance to the Query instance
static javax.persistence.criteria.Predicate	basicCreatePredicateFromSingleCriteria(javax.persistence.criteria.CriteriaBuilder builder, javax.persistence.criteria.Expression entityField, QueryCriteria criteria) This method creates the basic types of Predicate from trivial QueryCriteria (NORMAL/REGEXP/RANGE).
static <C,I> List<I>	convertListToInterfaceList(List<C> internalResult, Class<I> interfaceType)
protected static String	convertRegexToJPALikeExpression(String regexInput) Conver the regex (parameter) string to the JPA like syntax
protected abstract <T> List<T>	createQueryAndCallApplyMetaCriteriaAndGetResult(QueryWhere queryWhere, javax.persistence.criteria.CriteriaQuery<T> criteriaQuery, javax.persistence.criteria.CriteriaBuilder builder) This method does the persistence-related logic related to executing a query.
static <T> javax.persistence.criteria.Expression	defaultGetEntityField(javax.persistence.criteria.CriteriaQuery<T> query, String listId, javax.persistence.metamodel.Attribute attr)
<T> List<T>	doCriteriaQuery(QueryWhere queryWhere, Class<T> queryType) This method takes the high-level steps needed in order to create a JPA CriteriaQuery.
protected <R,T> void	fillCriteriaQuery(javax.persistence.criteria.CriteriaQuery<R> query, QueryWhere queryWhere, javax.persistence.criteria.CriteriaBuilder builder, Class<T> queryType) This is the main ("highest"?
protected Map<Class,Map<String,javax.persistence.metamodel.Attribute>>	getCriteriaAttributes()
protected abstract javax.persistence.criteria.CriteriaBuilder	getCriteriaBuilder()
protected <T> javax.persistence.criteria.Expression	getEntityField(javax.persistence.criteria.CriteriaQuery<T> query, String listId, javax.persistence.metamodel.Attribute attr) This method retrieves the entity "field" that can be used as the LHS of a Predicate This method is overridden in some extended QueryCriteriaUtil implementations
protected <T,R> javax.persistence.criteria.Expression	getOrderByExpression(javax.persistence.criteria.CriteriaQuery<R> query, Class<T> queryType, String orderByListId)
static <T> javax.persistence.criteria.Root	getRoot(javax.persistence.criteria.AbstractQuery<T> query, Class queryType) This is a helper method to retrieve a particular Root from a CriteriaQuery instance
protected abstract <R,T> javax.persistence.criteria.Predicate	implSpecificCreatePredicateFromSingleCriteria(javax.persistence.criteria.CriteriaQuery<R> query, javax.persistence.criteria.CriteriaBuilder builder, Class queryType, QueryCriteria criteria, QueryWhere queryWhere) Some criteria do not directly refer to a field, such as those stored in the criteria attributes Map> passed as an argument to the constructor.
protected void	initialize(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes)
protected abstract boolean	initializeCriteriaAttributes() The implementation of this method should be synchronized!

Methods inherited from class java.lang.Object

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

Constructor Detail

QueryCriteriaUtil

public QueryCriteriaUtil(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes)

QueryCriteriaUtil

protected QueryCriteriaUtil()

Method Detail

initialize

protected void initialize(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes)

getCriteriaAttributes

protected Map<Class,Map<String,javax.persistence.metamodel.Attribute>> getCriteriaAttributes()

convertListToInterfaceList

public static <C,I> List<I> convertListToInterfaceList(List<C> internalResult,
                                                       Class<I> interfaceType)

addCriteria

public static void addCriteria(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes,
                               String listId,
                               javax.persistence.metamodel.Attribute attr)

addCriteria

public static void addCriteria(Map<Class,Map<String,javax.persistence.metamodel.Attribute>> criteriaAttributes,
                               String listId,
                               Class table,
                               javax.persistence.metamodel.Attribute attr)

initializeCriteriaAttributes

protected abstract boolean initializeCriteriaAttributes()

The implementation of this method should be synchronized!

getCriteriaBuilder

protected abstract javax.persistence.criteria.CriteriaBuilder getCriteriaBuilder()

doCriteriaQuery

public <T> List<T> doCriteriaQuery(QueryWhere queryWhere,
                                   Class<T> queryType)

This method takes the high-level steps needed in order to create a JPA CriteriaQuery.

1. A CriteriaBuilder and CriteriaQuery instance are created.
2. The tables being selected from are defined in the query.
3. The CriteriaQuery instance is filled using the criteria in the QueryWhere instance
4. A JPA Query instance is created
5. The meta criteria (max results, offset) are applied to the query
6. The results are retrieved and returned

Parameters:

queryWhere - a QueryWhere instance containing the query criteria

queryType - The type (Class) of the result

Returns:

The result of the query, a List.

fillCriteriaQuery

protected <R,T> void fillCriteriaQuery(javax.persistence.criteria.CriteriaQuery<R> query,
                                       QueryWhere queryWhere,
                                       javax.persistence.criteria.CriteriaBuilder builder,
                                       Class<T> queryType)

This is the main ("highest"? "most abstract"?) method that is used to create a CriteriaQuery from a QueryWhere instance.

Parameters:

query - The (empty) CriteriaQuery that will be filled using the QueryCriteria and other information in the QueryWhere instance

queryWhere - The QueryWhere instance, with abstract information that should be added to the CriteriaQuery

builder - The CriteriaBuilder, helpful when creating Predicates to add to the CriteriaQuery

queryType - The Class indicating the main Root of the CriteriaQuery

getRoot

public static <T> javax.persistence.criteria.Root getRoot(javax.persistence.criteria.AbstractQuery<T> query,
                                                          Class queryType)

This is a helper method to retrieve a particular Root from a CriteriaQuery instance

Parameters:

query - The CriteriaQuery instance that we're building

queryType - The Class matching the Root we want

Returns:

The Root matching the given Class or null if it's not in the query

getEntityField

protected <T> javax.persistence.criteria.Expression getEntityField(javax.persistence.criteria.CriteriaQuery<T> query,
                                                                   String listId,
                                                                   javax.persistence.metamodel.Attribute attr)

This method retrieves the entity "field" that can be used as the LHS of a Predicate

This method is overridden in some extended QueryCriteriaUtil implementations

Parameters:

query - The CriteriaQuery that we're building

listId - The list id of the given QueryCriteria

Returns:

An Expression with the Path to the field represented by the QueryCriteria.getListId() value

defaultGetEntityField

public static <T> javax.persistence.criteria.Expression defaultGetEntityField(javax.persistence.criteria.CriteriaQuery<T> query,
                                                                              String listId,
                                                                              javax.persistence.metamodel.Attribute attr)

basicCreatePredicateFromSingleCriteria

public static javax.persistence.criteria.Predicate basicCreatePredicateFromSingleCriteria(javax.persistence.criteria.CriteriaBuilder builder,
                                                                                          javax.persistence.criteria.Expression entityField,
                                                                                          QueryCriteria criteria)

This method creates the basic types of Predicate from trivial QueryCriteria (NORMAL/REGEXP/RANGE).

Parameters:

builder - The CriteriaBuilder, helpful when creating Predicates to add to the CriteriaQuery

entityField - The Expression representing a field/column in an entity/table.

criteria - The QueryCriteria with the values to use as the RHS of a Predicate

Returns:

The created Predicate

convertRegexToJPALikeExpression

protected static String convertRegexToJPALikeExpression(String regexInput)

Conver the regex (parameter) string to the JPA like syntax

Parameters:

regexInput - The parameter string

Returns:

The String in JPA syntax for a regular expressions

implSpecificCreatePredicateFromSingleCriteria

protected abstract <R,T> javax.persistence.criteria.Predicate implSpecificCreatePredicateFromSingleCriteria(javax.persistence.criteria.CriteriaQuery<R> query,
                                                                                                            javax.persistence.criteria.CriteriaBuilder builder,
                                                                                                            Class queryType,
                                                                                                            QueryCriteria criteria,
                                                                                                            QueryWhere queryWhere)

Some criteria do not directly refer to a field, such as those stored in the criteria attributes Map> passed as an argument to the constructor.

For example, the QueryParameterIdentifiers.LAST_VARIABLE_LIST criteria specifies that only the most recent VariableInstanceLog should be retrieved.

This method is called from the #createPredicateFromSingleCriteria(CriteriaQuery, QueryCriteria, CriteriaBuilder, Class) method when no Attribute instance can be found in the instances criteria attributes Map>.

Parameters:

criteriaQuery - The CriteriaQuery instance.

criteria - The QueryCriteria instance with the criteria information.

criteriaBuilder - The CriteriaBuilder instance used to help create the query predicate.

queryType - The Class of the query, used to identify the type of query

resultType - The Class of the result being request.

Returns:

A Predicate representin the information in the QueryCriteria instance.

createQueryAndCallApplyMetaCriteriaAndGetResult

protected abstract <T> List<T> createQueryAndCallApplyMetaCriteriaAndGetResult(QueryWhere queryWhere,
                                                                               javax.persistence.criteria.CriteriaQuery<T> criteriaQuery,
                                                                               javax.persistence.criteria.CriteriaBuilder builder)

This method does the persistence-related logic related to executing a query.

All implementations of this method should do the following, in approximately the following order:

1. Get an EntityManager instance
2. Join a transaction using the entity manager
3. Create a Query from the given CriteriaQuery instance.
4. Call the applyMetaCriteriaToQuery(Query, QueryWhere) method
5. Retrieve the result from the Query instance.
6. Close the transaction created, and the created EntityManager instance.
7. Return the query result

Parameters:

criteriaQuery - The created and filled CriteriaQuery instance

builder - The CriteriaBuilder, helpful when creating Predicates to add to the CriteriaQuery

queryWhere - The QueryWhere instance containing the meta criteria information.

Returns:

A List of instances, representing the query result.

applyMetaCriteriaToQuery

public static void applyMetaCriteriaToQuery(javax.persistence.Query query,
                                            QueryWhere queryWhere)

Small method to apply the meta criteria from the QueryWhere instance to the Query instance

Parameters:

query - The Query instance

queryWhere - The QueryWhere instance, with the abstract information about the query

getOrderByExpression

protected <T,R> javax.persistence.criteria.Expression getOrderByExpression(javax.persistence.criteria.CriteriaQuery<R> query,
                                                                           Class<T> queryType,
                                                                           String orderByListId)

Parameters:

orderByListId -

queryType -

query -

Returns: