# OneToOneOwnedBySourceConfigurer.java

    package org.codefilarete.stalactite.engine.configurer.onetoone;

    import java.util.HashMap;
    import java.util.Map;

    import org.codefilarete.reflection.AccessorDefinition;
    import org.codefilarete.reflection.Mutator;
    import org.codefilarete.stalactite.dsl.naming.ForeignKeyNamingStrategy;
    import org.codefilarete.stalactite.dsl.naming.JoinColumnNamingStrategy;
    import org.codefilarete.stalactite.dsl.naming.UniqueConstraintNamingStrategy;
    import org.codefilarete.stalactite.dsl.property.CascadeOptions.RelationMode;
    import org.codefilarete.stalactite.engine.runtime.ConfiguredPersister;
    import org.codefilarete.stalactite.engine.runtime.ConfiguredRelationalPersister;
    import org.codefilarete.stalactite.engine.runtime.load.EntityJoinTree;
    import org.codefilarete.stalactite.engine.runtime.load.EntityJoinTree.JoinType;
    import org.codefilarete.stalactite.engine.runtime.load.PassiveJoinNode;
    import org.codefilarete.stalactite.engine.runtime.load.RelationJoinNode;
    import org.codefilarete.stalactite.engine.runtime.onetoone.OneToOneOwnedBySourceEngine;
    import org.codefilarete.stalactite.mapping.EntityMapping;
    import org.codefilarete.stalactite.sql.ddl.structure.Column;
    import org.codefilarete.stalactite.sql.ddl.structure.Key;
    import org.codefilarete.stalactite.sql.ddl.structure.Key.KeyBuilder;
    import org.codefilarete.stalactite.sql.ddl.structure.Table;
    import org.codefilarete.stalactite.sql.result.BeanRelationFixer;
    import org.codefilarete.tool.Duo;
    import org.codefilarete.tool.collection.KeepOrderSet;

    import static org.codefilarete.tool.Nullable.nullable;

    /**
     * @param <SRC> type of input (left/source entities)
     * @param <TRGT> type of output (right/target entities)
     * @param <SRCID> identifier type of source entities
     * @param <TRGTID> identifier type of target entities
     * @param <LEFTTABLE> left (source entity) table type
     * @param <RIGHTTABLE> right (target entity) table type
     * @param <JOINID> joining columns type
     * @author Guillaume Mary
     */
    public class OneToOneOwnedBySourceConfigurer<SRC, TRGT, SRCID, TRGTID, LEFTTABLE extends Table<LEFTTABLE>, RIGHTTABLE extends Table<RIGHTTABLE>, JOINID>
    		extends OneToOneConfigurerTemplate<SRC, TRGT, SRCID, TRGTID, LEFTTABLE, RIGHTTABLE, JOINID> {

    	private final JoinColumnNamingStrategy joinColumnNamingStrategy;

    	private final ForeignKeyNamingStrategy foreignKeyNamingStrategy;

    	private final Map<Column<LEFTTABLE, ?>, Column<RIGHTTABLE, ?>> keyColumnsMapping = new HashMap<>();

    	private OneToOneOwnedBySourceEngine<SRC, TRGT, SRCID, TRGTID, LEFTTABLE, RIGHTTABLE> engine;

    	public OneToOneOwnedBySourceConfigurer(ConfiguredRelationalPersister<SRC, SRCID> sourcePersister,
    										   OneToOneRelation<SRC, TRGT, TRGTID> oneToOneRelation,
    										   JoinColumnNamingStrategy joinColumnNamingStrategy,
    										   ForeignKeyNamingStrategy foreignKeyNamingStrategy,
    										   UniqueConstraintNamingStrategy uniqueConstraintNamingStrategy) {
    		super(sourcePersister, oneToOneRelation, uniqueConstraintNamingStrategy);
    		this.joinColumnNamingStrategy = joinColumnNamingStrategy;
    		this.foreignKeyNamingStrategy = foreignKeyNamingStrategy;
    	}

    	@Override
    	protected BeanRelationFixer<SRC, TRGT> determineRelationFixer() {
    		Mutator<SRC, TRGT> targetSetter = oneToOneRelation.getTargetProvider().toMutator();
    		return BeanRelationFixer.of(targetSetter::set);
    	}

    	@Override
    	protected Duo<Key<LEFTTABLE, JOINID>, Key<RIGHTTABLE, JOINID>> determineForeignKeyColumns(EntityMapping<SRC, SRCID, LEFTTABLE> mappingStrategy,
    																							  EntityMapping<TRGT, TRGTID, RIGHTTABLE> targetMappingStrategy) {
    		Key<RIGHTTABLE, JOINID> rightKey = targetMappingStrategy.getTargetTable().getPrimaryKey();
    		// adding foreign key constraint
    		KeyBuilder<LEFTTABLE, JOINID> leftKeyBuilder = Key.from(mappingStrategy.getTargetTable());
    		AccessorDefinition accessorDefinition = AccessorDefinition.giveDefinition(oneToOneRelation.getTargetProvider());
    		targetMappingStrategy.getTargetTable().getPrimaryKey().getColumns().forEach(column -> {
    			String effectiveLeftColumnName = nullable(oneToOneRelation.getColumnName()).elseSet(() -> joinColumnNamingStrategy.giveName(accessorDefinition, column)).get();
    			Column<LEFTTABLE, ?> foreignKeyColumn = mappingStrategy.getTargetTable().addColumn(effectiveLeftColumnName, column.getJavaType());
    			leftKeyBuilder.addColumn(foreignKeyColumn);
    			keyColumnsMapping.put(foreignKeyColumn, column);
    		});
    		Key<LEFTTABLE, JOINID> leftKey = leftKeyBuilder.build();

    		// According to the nullable option, we specify the ddl schema option
    		leftKey.getColumns().forEach(c -> ((Column) c).nullable(oneToOneRelation.isNullable()));

    		// we don't create foreign key for table-per-class because source columns should reference different tables (the one
    		// per entity) which databases do not allow
    		boolean createForeignKey = !oneToOneRelation.isTargetTablePerClassPolymorphic();
    		if (createForeignKey) {
    			String foreignKeyName = foreignKeyNamingStrategy.giveName(leftKey, rightKey);
    			sourcePersister.<LEFTTABLE>getMapping().getTargetTable().addForeignKey(foreignKeyName, leftKey, rightKey);
    		}

    		return new Duo<>(leftKey, rightKey);
    	}

    	@Override
    	protected void addUniqueConstraint(Column<?, ?> column) {
    		String constraintName = uniqueConstraintNamingStrategy.giveName(oneToOneRelation.getTargetProvider(), column);
    		column.getTable().addUniqueConstraint(constraintName, column);
    	}

    	@Override
    	protected void addSelectIn2Phases(
    			String tableAlias,
    			ConfiguredRelationalPersister<TRGT, TRGTID> targetPersister,
    			Key<LEFTTABLE, JOINID> leftKey,
    			Key<RIGHTTABLE, JOINID> rightKey,
    			FirstPhaseCycleLoadListener<SRC, TRGTID> firstPhaseCycleLoadListener) {

    		Table targetTableClone = new Table(targetPersister.getMapping().getTargetTable().getName());
    		KeepOrderSet<Column> columns = (KeepOrderSet<Column>) (KeepOrderSet) rightKey.getColumns();
    		columns.forEach(column -> targetTableClone.addColumn(column.getExpression(), column.getJavaType()).primaryKey());
    		// This can't be done directly on root persister (took via persisterRegistry and targetPersister.getClassToPersist()) because
    		// TransformerListener would get root instance as source (aggregate root), not current source
    		String joinName = sourcePersister.getEntityJoinTree().addPassiveJoin(
    				EntityJoinTree.ROOT_JOIN_NAME,
    				leftKey,
    				targetTableClone.getPrimaryKey(),
    				tableAlias,
    				oneToOneRelation.isNullable() ? JoinType.OUTER : JoinType.INNER,
    				targetTableClone.getPrimaryKey().getColumns(),
    				(src, columnValueProvider) -> firstPhaseCycleLoadListener.onFirstPhaseRowRead(src, targetPersister.getMapping().getIdMapping().getIdentifierAssembler().assemble(columnValueProvider)),
    				true);

    		// Propagating 2-phases load to all nodes that use cycling type
    		PassiveJoinNode passiveJoin = (PassiveJoinNode) sourcePersister.getEntityJoinTree().getJoin(joinName);
    		targetPersister.getEntityJoinTree().foreachJoin(joinNode -> {
    			if (joinNode instanceof RelationJoinNode
    					&& ((RelationJoinNode<?, ?, ?, ?, ?>) joinNode).getEntityInflater().getEntityType() == sourcePersister.getClassToPersist()) {
    				EntityJoinTree.cloneNodeForParent(passiveJoin, joinNode, leftKey);
    			}
    		});
    	}

    	@Override
    	protected void addWriteCascades(ConfiguredPersister<TRGT, TRGTID> targetPersister) {
    		this.engine = new OneToOneOwnedBySourceEngine<>(sourcePersister, targetPersister, oneToOneRelation.getTargetProvider(), keyColumnsMapping);
    		boolean writeAuthorized = oneToOneRelation.getRelationMode() != RelationMode.READ_ONLY;
    		if (writeAuthorized) {
    			super.addWriteCascades(targetPersister);
    		} else {
    			// even if write is not authorized, we still have to insert and update source-to-target link, because we are in relation-owned-by-source
    			this.engine.addForeignKeyMaintainer();
    		}
    	}

    	@Override
    	protected void addInsertCascade(ConfiguredPersister<TRGT, TRGTID> targetPersister) {
    		super.addInsertCascade(targetPersister);
    		engine.addInsertCascade();
    	}

    	@Override
    	protected void addUpdateCascade(ConfiguredPersister<TRGT, TRGTID> targetPersister, boolean orphanRemoval) {
    		super.addUpdateCascade(targetPersister, orphanRemoval);
    		engine.addUpdateCascade(orphanRemoval);
    	}

    	@Override
    	protected void addDeleteCascade(ConfiguredPersister<TRGT, TRGTID> targetPersister, boolean orphanRemoval) {
    		engine.addDeleteCascade(orphanRemoval);
    	}
    }