Package com.evolveum.midpoint.repo.sqlbase

Class SqlQueryContext<S,Q extends FlexibleRelationalPathBase<R>,R>

java.lang.Object

com.evolveum.midpoint.repo.sqlbase.SqlQueryContext<S,Q,R>

Type Parameters:

S - schema type, used by encapsulated mapping

Q - type of entity path

R - row type related to the SqlQueryContext

All Implemented Interfaces:

FilterProcessor<ObjectFilter>

public abstract class SqlQueryContext<S,Q extends FlexibleRelationalPathBase<R>,R>
extends Object
implements FilterProcessor<ObjectFilter>

Execution context of the SQL query. Works as a kind of accumulator where information are added as the object query is interpreted. The object has a couple of overlapping responsibilities: * It implements FilterProcessor and is used as an entry point for filter processing for the query. * It executes the query, returning PageOf low-level rows, see executeQuery(com.evolveum.midpoint.repo.sqlbase.JdbcSession). * It transforms the row beans to midPoint objects using transformToSchemaType(com.evolveum.midpoint.repo.sqlbase.PageOf<com.querydsl.core.Tuple>, com.evolveum.midpoint.repo.sqlbase.JdbcSession). QueryTableMapping is crucial for all these steps and flow of the execution goes a lot between the SqlQueryExecutor, this class and particular methods of the mapping. Anything specific for a particular type/table should be part of the mapping logic. The mapping contract should cover all the needs of this execution context. It can be extended if needed, but always think whether existing mechanisms are not enough already. E.g. if you need to post-process the low level result, there is a way how to do it and it allows for things like loading all the detail table rows in a single query. See transformToSchemaType(com.evolveum.midpoint.repo.sqlbase.PageOf<com.querydsl.core.Tuple>, com.evolveum.midpoint.repo.sqlbase.JdbcSession) for notes how this allows for inter-row state keeping as well. [NOTE] Implementation note: There was an option to keep this as an information accumulator only and do the execution elsewhere, but it proved more practical to utilize all the contained parameterized types. Methods executing the query and processing the result would need to be parameterized the same way this context already is - so it was better to use the types here. [NOTE] This object does not handle SQL connections or transaction in any way, any connection needed is provided from the outside.

Field Summary

Fields

Modifier and Type	Field	Description
static int	DEFAULT_PAGE_SIZE	Default page size if pagination is requested, that is offset is set, but maxSize is not.
protected Q	entityPath
protected QueryTableMapping<S,Q,R>	entityPathMapping
static int	MAX_ID_IN_FOR_TO_MANY_FETCH	Number of values (identifiers) used in the IN clause to-many fetching selects.
static long	NO_PAGINATION_LIMIT	If no other limit is used for query this limit will be used for sanity reasons.
protected boolean	notFilterUsed
protected Collection<SelectorOptions<GetOperationOptions>>	options
protected com.querydsl.sql.SQLQuery<?>	sqlQuery

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	SqlQueryContext(Q entityPath, QueryTableMapping<S,Q,R> mapping, SqlQueryContext<?,?,?> parentContext, com.querydsl.sql.SQLQuery<?> sqlQuery)	Constructor for derived context or sub-context, e.g.
protected	SqlQueryContext(Q entityPath, QueryTableMapping<S,Q,R> mapping, SqlRepoContext sqlRepoContext, com.querydsl.sql.SQLQuery<?> query)	Constructor for root query context.

Method Summary

Modifier and Type	Method	Description
void	beforeQuery()	Before-query hook, empty by default, called *before* the JDBC transaction starts.
CanonicalItemPath	createCanonicalItemPath(@NotNull ItemPath itemPath)
int	executeCount(JdbcSession jdbcSession)
PageOf<com.querydsl.core.Tuple>	executeQuery(JdbcSession jdbcSession)	Returns page of results with each row represented by a Tuple.
boolean	isNotFilterUsed()
<TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR>	leftJoin(@NotNull QueryTableMapping<TS,TQ,TR> targetMapping, @NotNull BiFunction<Q,TQ,com.querydsl.core.types.Predicate> joinOnPredicateFunction)	Adds new LEFT JOIN to the query and returns SqlQueryContext for this join path.
QueryTableMapping<S,Q,R>	mapping()
void	markNotFilterUsage()
protected abstract <TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR>	newSubcontext(TQ newPath, QueryTableMapping<TS,TQ,TR> newMapping)	Contract to implement to obtain derived (e.g.
protected abstract <TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR>	newSubcontext(TQ newPath, QueryTableMapping<TS,TQ,TR> newMapping, com.querydsl.sql.SQLQuery<?> query)	Contract to implement to obtain derived (e.g.
@NotNull QName	normalizeRelation(QName qName)
SqlQueryContext<?,?,?>	parentContext()
Q	path()	Returns entity path of this context.
<T extends FlexibleRelationalPathBase<?>> T	path(Class<T> pathType)
PrismContext	prismContext()
com.querydsl.core.types.Predicate	process(@NotNull ObjectFilter filter)	Implements contract for FilterProcessor working as a top-level dispatcher to concrete filter types.
void	processFilter(ObjectFilter filter)	Processes the object filter and sets the WHERE clause.
void	processObjectPaging(ObjectPaging paging)	This method takes care of ObjectPaging which includes ordering.
void	processOptions(Collection<SelectorOptions<GetOperationOptions>> options)
<T> Class<? extends T>	qNameToSchemaClass(@NotNull QName qName)
SqlRepoContext	repositoryContext()
Q	root()
<T extends FlexibleRelationalPathBase<?>> T	root(Class<T> rootType)
com.querydsl.sql.SQLQuery<?>	sqlQuery()	Returns wrapped query if usage of Querydsl API is more convenient.
<TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR>	subquery(@NotNull QueryTableMapping<TS,TQ,TR> targetMapping)	Creates new subquery and returns SqlQueryContext for it, typically for (NOT) EXISTS.
<TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR>	subquery(@NotNull Class<TQ> subqueryType)	Creates new subquery, see subquery(QueryTableMapping) for more.
PageOf<S>	transformToSchemaType(PageOf<com.querydsl.core.Tuple> result, JdbcSession jdbcSession)	Transforms result page with (bean + extension columns) tuple to schema type.
String	uniqueAliasName(String baseAliasName)

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.evolveum.midpoint.repo.sqlbase.filtering.FilterProcessor

process

Field Detail

DEFAULT_PAGE_SIZE

public static final int DEFAULT_PAGE_SIZE

Default page size if pagination is requested, that is offset is set, but maxSize is not.

See Also:

Constant Field Values

NO_PAGINATION_LIMIT

public static final long NO_PAGINATION_LIMIT

If no other limit is used for query this limit will be used for sanity reasons.

See Also:

Constant Field Values

MAX_ID_IN_FOR_TO_MANY_FETCH

public static final int MAX_ID_IN_FOR_TO_MANY_FETCH

Number of values (identifiers) used in the IN clause to-many fetching selects. This works effectively as factor of how bad N+1 select is, it's at most N/this-limit+1 bad. For obvious reasons, this works only for non-composite PKs (IDs) on the master entity.

See Also:

Constant Field Values

sqlQuery

protected final com.querydsl.sql.SQLQuery<?> sqlQuery

entityPath

protected final Q extends FlexibleRelationalPathBase<R> entityPath

entityPathMapping

protected final QueryTableMapping<S,Q extends FlexibleRelationalPathBase<R>,R> entityPathMapping

notFilterUsed

protected boolean notFilterUsed

options

protected Collection<SelectorOptions<GetOperationOptions>> options

Constructor Detail

SqlQueryContext

protected SqlQueryContext(Q entityPath,
                          QueryTableMapping<S,Q,R> mapping,
                          SqlRepoContext sqlRepoContext,
                          com.querydsl.sql.SQLQuery<?> query)

Constructor for root query context.

SqlQueryContext

protected SqlQueryContext(Q entityPath,
                          QueryTableMapping<S,Q,R> mapping,
                          SqlQueryContext<?,?,?> parentContext,
                          com.querydsl.sql.SQLQuery<?> sqlQuery)

Constructor for derived context or sub-context, e.g. JOIN, EXISTS, etc.

Method Detail

root

public Q root()

root

public <T extends FlexibleRelationalPathBase<?>> T root(Class<T> rootType)

processFilter

public void processFilter(ObjectFilter filter)
                   throws RepositoryException

Processes the object filter and sets the WHERE clause. This is different from process(ObjectFilter) that just creates a predicate. That method is used in this one and QueryBase.where(Predicate) is called.

Throws:

RepositoryException

process

public com.querydsl.core.types.Predicate process(@NotNull
                                                 @NotNull ObjectFilter filter)
                                          throws RepositoryException

Implements contract for FilterProcessor working as a top-level dispatcher to concrete filter types. This is a universal/generic filter processor that dispatches to the actual filter processor based on the filter type. It is used both as an entry point for the root filter of the query, but also when various structural filters need to resolve their components (e.g. AND uses this for its components). *This only returns the created predicate, compare with processFilter(com.evolveum.midpoint.prism.query.ObjectFilter).* Some subtypes of ObjectFilter from Prism API are not supported here, see subclasses.

Specified by:

process in interface FilterProcessor<S>

Throws:

RepositoryException

processObjectPaging

public void processObjectPaging(ObjectPaging paging)
                         throws RepositoryException

This method takes care of ObjectPaging which includes ordering.

Throws:

RepositoryException

executeQuery

public PageOf<com.querydsl.core.Tuple> executeQuery(JdbcSession jdbcSession)
                                             throws QueryException

Returns page of results with each row represented by a Tuple. Tuple contains expressions specified by QueryTableMapping.selectExpressions(Q, java.util.Collection<com.evolveum.midpoint.schema.SelectorOptions<com.evolveum.midpoint.schema.GetOperationOptions>>), see buildSelectExpressions(Q, com.querydsl.sql.SQLQuery<?>) for details. This may for example be SqlQueryContext (representing the whole entity) and then individual paths for extension columns, see extensionColumns in QueryTableMapping. QueryTableMapping has many responsibilities in the process: * options are used to amend the select expression list; the options later enter as a parameter to most methods related to the transformation from row to midPoint object. * QueryTableMapping.createRowTransformer(com.evolveum.midpoint.repo.sqlbase.SqlQueryContext<S, Q, R>, com.evolveum.midpoint.repo.sqlbase.JdbcSession) (used later by transformToSchemaType(com.evolveum.midpoint.repo.sqlbase.PageOf<com.querydsl.core.Tuple>, com.evolveum.midpoint.repo.sqlbase.JdbcSession)) allows for low-level result list processing, e.g. fetching any additional objects efficiently.

Throws:

QueryException

executeCount

public int executeCount(JdbcSession jdbcSession)

leftJoin

public <TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR> leftJoin(@NotNull
                                                                                                                    @NotNull QueryTableMapping<TS,TQ,TR> targetMapping,
                                                                                                                    @NotNull
                                                                                                                    @NotNull BiFunction<Q,TQ,com.querydsl.core.types.Predicate> joinOnPredicateFunction)

Adds new LEFT JOIN to the query and returns SqlQueryContext for this join path. The returned context still uses the same SQL query; any further filter processing will add WHERE conditions to the original query, but the conditions use the new alias.

Type Parameters:

TQ - query type for the JOINed (target) table

TR - row type related to the SqlQueryContext

Parameters:

targetMapping - mapping for the JOIN target query type

joinOnPredicateFunction - bi-function producing ON predicate for the JOIN

subquery

public <TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR> subquery(@NotNull
                                                                                                                    @NotNull Class<TQ> subqueryType)

Creates new subquery, see subquery(QueryTableMapping) for more.

Parameters:

subqueryType - entity path type the subquery

subquery

public <TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR> subquery(@NotNull
                                                                                                                    @NotNull QueryTableMapping<TS,TQ,TR> targetMapping)

Creates new subquery and returns SqlQueryContext for it, typically for (NOT) EXISTS. Call to FetchableSubQueryBase.exists() can't be here, because it's a predicate creating call that we may need to execute when returning the predicate inside the filter processor. See `TypeFilterProcessor` from `repo-sqale` for example.

Type Parameters:

TQ - query type for the subquery table

TR - row type related to the SqlQueryContext

Parameters:

targetMapping - mapping for the subquery type

newSubcontext

protected abstract <TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR> newSubcontext(TQ newPath,
                                                                                                                                     QueryTableMapping<TS,TQ,TR> newMapping)

Contract to implement to obtain derived (e.g. joined) query context.

Type Parameters:

TQ - query type for the new (target) table

TR - row type related to the SqlQueryContext

newSubcontext

protected abstract <TS,TQ extends FlexibleRelationalPathBase<TR>,TR> SqlQueryContext<TS,TQ,TR> newSubcontext(TQ newPath,
                                                                                                                                     QueryTableMapping<TS,TQ,TR> newMapping,
                                                                                                                                     com.querydsl.sql.SQLQuery<?> query)

Contract to implement to obtain derived (e.g. subquery) query context.

Type Parameters:

TQ - query type for the new (target) table

TR - row type related to the SqlQueryContext

uniqueAliasName

public String uniqueAliasName(String baseAliasName)

processOptions

public void processOptions(Collection<SelectorOptions<GetOperationOptions>> options)

transformToSchemaType

public PageOf<S> transformToSchemaType(PageOf<com.querydsl.core.Tuple> result,
                                       JdbcSession jdbcSession)
                                throws SchemaException,
                                       QueryException

Transforms result page with (bean + extension columns) tuple to schema type. JDBC session is provided as it may be needed for additional fetches. Instead of calling some transformation method row-by-row, transformer object is provided by the table mapper - which allows for potentially stateful processing.

Throws:

SchemaException

QueryException

sqlQuery

public com.querydsl.sql.SQLQuery<?> sqlQuery()

Returns wrapped query if usage of Querydsl API is more convenient.

parentContext

public SqlQueryContext<?,?,?> parentContext()

path

public Q path()

Returns entity path of this context.

path

public <T extends FlexibleRelationalPathBase<?>> T path(Class<T> pathType)

mapping

public QueryTableMapping<S,Q,R> mapping()

markNotFilterUsage

public void markNotFilterUsage()

isNotFilterUsed

public boolean isNotFilterUsed()

repositoryContext

public SqlRepoContext repositoryContext()

prismContext

public PrismContext prismContext()

qNameToSchemaClass

public <T> Class<? extends T> qNameToSchemaClass(@NotNull
                                                 @NotNull QName qName)

createCanonicalItemPath

public CanonicalItemPath createCanonicalItemPath(@NotNull
                                                 @NotNull ItemPath itemPath)

normalizeRelation

@NotNull
public @NotNull QName normalizeRelation(QName qName)

beforeQuery

public void beforeQuery()

Before-query hook, empty by default, called *before* the JDBC transaction starts.