/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.loader.plan.exec.internal;
import java.util.ArrayList;
import java.util.List;
import org.hibernate.engine.spi.SessionFactoryImplementor;
import org.hibernate.loader.MultipleBagFetchException;
import org.hibernate.loader.plan.build.spi.LoadPlanTreePrinter;
import org.hibernate.loader.plan.exec.process.internal.ResultSetProcessorImpl;
import org.hibernate.loader.plan.exec.process.spi.CollectionReferenceInitializer;
import org.hibernate.loader.plan.exec.process.spi.EntityReferenceInitializer;
import org.hibernate.loader.plan.exec.process.spi.ReaderCollector;
import org.hibernate.loader.plan.exec.process.spi.ResultSetProcessor;
import org.hibernate.loader.plan.exec.query.internal.SelectStatementBuilder;
import org.hibernate.loader.plan.exec.query.spi.QueryBuildingParameters;
import org.hibernate.loader.plan.exec.spi.AliasResolutionContext;
import org.hibernate.loader.plan.exec.spi.LoadQueryDetails;
import org.hibernate.loader.plan.spi.CollectionAttributeFetch;
import org.hibernate.loader.plan.spi.CollectionReturn;
import org.hibernate.loader.plan.spi.FetchSource;
import org.hibernate.loader.plan.spi.LoadPlan;
import org.hibernate.loader.plan.spi.QuerySpace;
import org.hibernate.loader.plan.spi.Return;
import org.hibernate.sql.ConditionFragment;
import org.hibernate.sql.DisjunctionFragment;
import org.hibernate.sql.InFragment;
/**
* @author Gail Badner
*/
public abstract class AbstractLoadQueryDetails implements LoadQueryDetails {
private final LoadPlan loadPlan;
private final String[] keyColumnNames;
private final Return rootReturn;
private final LoadQueryJoinAndFetchProcessor queryProcessor;
private String sqlStatement;
private ResultSetProcessor resultSetProcessor;
/**
* @param rootReturn The root return reference we are processing
* @param factory The SessionFactory
* @param buildingParameters The query building context
*/
protected AbstractLoadQueryDetails(
LoadPlan loadPlan,
AliasResolutionContextImpl aliasResolutionContext,
QueryBuildingParameters buildingParameters,
String[] keyColumnNames,
Return rootReturn,
SessionFactoryImplementor factory) {
this.keyColumnNames = keyColumnNames;
this.rootReturn = rootReturn;
this.loadPlan = loadPlan;
this.queryProcessor = new LoadQueryJoinAndFetchProcessor( aliasResolutionContext, buildingParameters, factory );
}
protected QuerySpace getQuerySpace(String querySpaceUid) {
return loadPlan.getQuerySpaces().getQuerySpaceByUid( querySpaceUid );
}
@Override
public String getSqlStatement() {
return sqlStatement;
}
@Override
public ResultSetProcessor getResultSetProcessor() {
return resultSetProcessor;
}
protected final Return getRootReturn() {
return rootReturn;
}
protected final AliasResolutionContext getAliasResolutionContext() {
return queryProcessor.getAliasResolutionContext();
}
protected final QueryBuildingParameters getQueryBuildingParameters() {
return queryProcessor.getQueryBuildingParameters();
}
protected final SessionFactoryImplementor getSessionFactory() {
return queryProcessor.getSessionFactory();
}
/**
* Main entry point for properly handling the FROM clause and and joins and restrictions
*
*/
protected void generate() {
// There are 2 high-level requirements to perform here:
// 1) Determine the SQL required to carry out the given LoadPlan (and fulfill
// {@code LoadQueryDetails#getSqlStatement()}). SelectStatementBuilder collects the ongoing efforts to
// build the needed SQL.
// 2) Determine how to read information out of the ResultSet resulting from executing the indicated SQL
// (the SQL aliases). ReaderCollector and friends are where this work happens, ultimately
// producing a ResultSetProcessor
final SelectStatementBuilder select = new SelectStatementBuilder( queryProcessor.getSessionFactory().getDialect() );
// LoadPlan is broken down into 2 high-level pieces that we need to process here.
//
// First is the QuerySpaces, which roughly equates to the SQL FROM-clause. We'll cycle through
// those first, generating aliases into the AliasContext in addition to writing SQL FROM-clause information
// into SelectStatementBuilder. The AliasContext is populated here and the reused while process the SQL
// SELECT-clause into the SelectStatementBuilder and then again also to build the ResultSetProcessor
applyRootReturnTableFragments( select );
if ( shouldApplyRootReturnFilterBeforeKeyRestriction() ) {
applyRootReturnFilterRestrictions( select );
// add restrictions...
// first, the load key restrictions (which entity(s)/collection(s) do we want to load?)
applyKeyRestriction(
select,
getRootTableAlias(),
keyColumnNames,
getQueryBuildingParameters().getBatchSize()
);
}
else {
// add restrictions...
// first, the load key restrictions (which entity(s)/collection(s) do we want to load?)
applyKeyRestriction(
select,
getRootTableAlias(),
keyColumnNames,
getQueryBuildingParameters().getBatchSize()
);
applyRootReturnFilterRestrictions( select );
}
applyRootReturnWhereJoinRestrictions( select );
applyRootReturnOrderByFragments( select );
// then move on to joins...
applyRootReturnSelectFragments( select );
queryProcessor.processQuerySpaceJoins( getRootQuerySpace(), select );
// Next, we process the Returns and Fetches building the SELECT clause and at the same time building
// Readers for reading the described results out of a SQL ResultSet
FetchStats fetchStats = null;
if ( FetchSource.class.isInstance( rootReturn ) ) {
fetchStats = queryProcessor.processFetches(
(FetchSource) rootReturn,
select,
getReaderCollector()
);
}
else if ( CollectionReturn.class.isInstance( rootReturn ) ) {
final CollectionReturn collectionReturn = (CollectionReturn) rootReturn;
if ( collectionReturn.getElementGraph() != null ) {
fetchStats = queryProcessor.processFetches(
collectionReturn.getElementGraph(),
select,
getReaderCollector()
);
}
// TODO: what about index???
}
if ( fetchStats != null && fetchStats.getJoinedBagAttributeFetches().size() > 1 ) {
final List<String> bagRoles = new ArrayList<>();
for ( CollectionAttributeFetch bagFetch : fetchStats.getJoinedBagAttributeFetches() ) {
bagRoles.add( bagFetch.getCollectionPersister().getRole() );
}
throw new MultipleBagFetchException( bagRoles );
}
LoadPlanTreePrinter.INSTANCE.logTree( loadPlan, queryProcessor.getAliasResolutionContext() );
this.sqlStatement = select.toStatementString();
this.resultSetProcessor = new ResultSetProcessorImpl(
loadPlan,
queryProcessor.getAliasResolutionContext(),
getReaderCollector().buildRowReader(),
shouldUseOptionalEntityInstance(),
isSubselectLoadingEnabled( fetchStats )
);
}
/**
* Is subselect loading enabled?
*
* @param fetchStats the fetch stats; may be null
* @return {@code true} if subselect loading is enabled; {@code false} otherwise.
*/
protected abstract boolean isSubselectLoadingEnabled(FetchStats fetchStats);
protected abstract boolean shouldUseOptionalEntityInstance();
protected abstract ReaderCollector getReaderCollector();
protected abstract QuerySpace getRootQuerySpace();
protected abstract String getRootTableAlias();
protected abstract boolean shouldApplyRootReturnFilterBeforeKeyRestriction();
protected abstract void applyRootReturnSelectFragments(SelectStatementBuilder selectStatementBuilder );
protected abstract void applyRootReturnTableFragments(SelectStatementBuilder selectStatementBuilder);
protected abstract void applyRootReturnFilterRestrictions(SelectStatementBuilder selectStatementBuilder);
protected abstract void applyRootReturnWhereJoinRestrictions(SelectStatementBuilder selectStatementBuilder);
protected abstract void applyRootReturnOrderByFragments(SelectStatementBuilder selectStatementBuilder);
private static void applyKeyRestriction(SelectStatementBuilder select, String alias, String[] keyColumnNames, int batchSize) {
if ( keyColumnNames.length==1 ) {
// NOT A COMPOSITE KEY
// for batching, use "foo in (?, ?, ?)" for batching
// for no batching, use "foo = ?"
// (that distinction is handled inside InFragment)
final InFragment in = new InFragment().setColumn( alias, keyColumnNames[0] );
for ( int i = 0; i < batchSize; i++ ) {
in.addValue( "?" );
}
select.appendRestrictions( in.toFragmentString() );
}
else {
// A COMPOSITE KEY...
final ConditionFragment keyRestrictionBuilder = new ConditionFragment()
.setTableAlias( alias )
.setCondition( keyColumnNames, "?" );
final String keyRestrictionFragment = keyRestrictionBuilder.toFragmentString();
StringBuilder restrictions = new StringBuilder();
if ( batchSize==1 ) {
// for no batching, use "foo = ? and bar = ?"
restrictions.append( keyRestrictionFragment );
}
else {
// for batching, use "( (foo = ? and bar = ?) or (foo = ? and bar = ?) )"
restrictions.append( '(' );
DisjunctionFragment df = new DisjunctionFragment();
for ( int i=0; i<batchSize; i++ ) {
df.addCondition( keyRestrictionFragment );
}
restrictions.append( df.toFragmentString() );
restrictions.append( ')' );
}
select.appendRestrictions( restrictions.toString() );
}
}
protected abstract static class ReaderCollectorImpl implements ReaderCollector {
private final List<EntityReferenceInitializer> entityReferenceInitializers = new ArrayList<EntityReferenceInitializer>();
private List<CollectionReferenceInitializer> arrayReferenceInitializers;
private List<CollectionReferenceInitializer> collectionReferenceInitializers;
@Override
public void add(CollectionReferenceInitializer collectionReferenceInitializer) {
if ( collectionReferenceInitializer.getCollectionReference().getCollectionPersister().isArray() ) {
if ( arrayReferenceInitializers == null ) {
arrayReferenceInitializers = new ArrayList<CollectionReferenceInitializer>();
}
arrayReferenceInitializers.add( collectionReferenceInitializer );
}
else {
if ( collectionReferenceInitializers == null ) {
collectionReferenceInitializers = new ArrayList<CollectionReferenceInitializer>();
}
collectionReferenceInitializers.add( collectionReferenceInitializer );
}
}
@Override
public void add(EntityReferenceInitializer entityReferenceInitializer) {
entityReferenceInitializers.add( entityReferenceInitializer );
}
@Override
public final List<EntityReferenceInitializer> getEntityReferenceInitializers() {
return entityReferenceInitializers;
}
@Override
public List<CollectionReferenceInitializer> getArrayReferenceInitializers() {
return arrayReferenceInitializers;
}
@Override
public List<CollectionReferenceInitializer> getNonArrayCollectionReferenceInitializers() {
return collectionReferenceInitializers;
}
}
}