//$Id: OneToManyJoinWalker.java 7627 2005-07-24 06:53:06Z oneovthafew $
package org.hibernate.loader.collection;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import org.hibernate.LockMode;
import org.hibernate.MappingException;
import org.hibernate.engine.SessionFactoryImplementor;
import org.hibernate.loader.BasicLoader;
import org.hibernate.loader.OuterJoinableAssociation;
import org.hibernate.persister.collection.QueryableCollection;
import org.hibernate.persister.entity.OuterJoinLoadable;
import org.hibernate.sql.JoinFragment;
import org.hibernate.sql.Select;
import org.hibernate.util.CollectionHelper;
import org.hibernate.util.StringHelper;
/**
* Walker for one-to-many associations
*
* @see OneToManyLoader
* @author Gavin King
*/
public class OneToManyJoinWalker extends CollectionJoinWalker {
private final QueryableCollection oneToManyPersister;
protected boolean isDuplicateAssociation(
final String foreignKeyTable,
final String[] foreignKeyColumns
) {
//disable a join back to this same association
final boolean isSameJoin = oneToManyPersister.getTableName().equals(foreignKeyTable) &&
Arrays.equals( foreignKeyColumns, oneToManyPersister.getKeyColumnNames() );
return isSameJoin ||
super.isDuplicateAssociation(foreignKeyTable, foreignKeyColumns);
}
public OneToManyJoinWalker(
QueryableCollection oneToManyPersister,
int batchSize,
String subquery,
SessionFactoryImplementor factory,
Map enabledFilters)
throws MappingException {
super(factory, enabledFilters);
this.oneToManyPersister = oneToManyPersister;
final OuterJoinLoadable elementPersister = (OuterJoinLoadable) oneToManyPersister.getElementPersister();
final String alias = generateRootAlias( oneToManyPersister.getRole() );
walkEntityTree(elementPersister, alias);
List allAssociations = new ArrayList();
allAssociations.addAll(associations);
allAssociations.add( new OuterJoinableAssociation(
oneToManyPersister.getCollectionType(),
null,
null,
alias,
JoinFragment.LEFT_OUTER_JOIN,
getFactory(),
CollectionHelper.EMPTY_MAP
) );
initPersisters(allAssociations, LockMode.NONE);
initStatementString(elementPersister, alias, batchSize, subquery);
}
private void initStatementString(
final OuterJoinLoadable elementPersister,
final String alias,
final int batchSize,
final String subquery)
throws MappingException {
final int joins = countEntityPersisters( associations );
suffixes = BasicLoader.generateSuffixes( joins + 1 );
final int collectionJoins = countCollectionPersisters( associations ) + 1;
collectionSuffixes = BasicLoader.generateSuffixes( joins + 1, collectionJoins );
StringBuffer whereString = whereString(
alias,
oneToManyPersister.getKeyColumnNames(),
subquery,
batchSize
);
String filter = oneToManyPersister.filterFragment( alias, getEnabledFilters() );
whereString.insert( 0, StringHelper.moveAndToBeginning(filter) );
JoinFragment ojf = mergeOuterJoins(associations);
Select select = new Select( getDialect() )
.setSelectClause(
oneToManyPersister.selectFragment(null, null, alias, suffixes[joins], collectionSuffixes[0], true) +
selectString(associations)
)
.setFromClause(
elementPersister.fromTableFragment(alias) +
elementPersister.fromJoinFragment(alias, true, true)
)
.setWhereClause( whereString.toString() )
.setOuterJoins(
ojf.toFromFragmentString(),
ojf.toWhereFragmentString() +
elementPersister.whereJoinFragment(alias, true, true)
);
select.setOrderByClause( orderBy( associations, oneToManyPersister.getSQLOrderByString(alias) ) );
if ( getFactory().getSettings().isCommentsEnabled() ) {
select.setComment( "load one-to-many " + oneToManyPersister.getRole() );
}
sql = select.toStatementString();
}
public String toString() {
return getClass().getName() + '(' + oneToManyPersister.getRole() + ')';
}
}