//$Id: OneToOne.java 7246 2005-06-20 20:32:36Z oneovthafew $package org.hibernate.mapping;import java.util.ArrayList;import java.util.Iterator;import org.hibernate.MappingException;import org.hibernate.type.EntityType;import org.hibernate.type.ForeignKeyDirection;import org.hibernate.type.SpecialOneToOneType;import org.hibernate.type.Type;import org.hibernate.type.TypeFactory;/** * A one-to-one association mapping * @author Gavin King */public class OneToOne extends ToOne {	private boolean constrained;	private ForeignKeyDirection foreignKeyType;	private KeyValue identifier;	private String propertyName;	private String entityName;	public OneToOne(Table table, PersistentClass owner) throws MappingException {		super(table);		this.identifier = owner.getKey();		this.entityName = owner.getEntityName();	}	public String getPropertyName() {		return propertyName;	}	public void setPropertyName(String propertyName) {		this.propertyName = propertyName==null ? null : propertyName.intern();	}		public String getEntityName() {		return entityName;	}	public void setEntityName(String propertyName) {		this.entityName = entityName==null ? null : entityName.intern();	}		public Type getType() throws MappingException {		if ( getColumnIterator().hasNext() ) {			return new SpecialOneToOneType(					getReferencedEntityName(), 					foreignKeyType, 					referencedPropertyName,					isLazy(),					isUnwrapProxy(),					entityName,					propertyName				);		}		else {			return TypeFactory.oneToOne( 					getReferencedEntityName(), 					foreignKeyType, 					referencedPropertyName,					isLazy(),					isUnwrapProxy(),					isEmbedded(),					entityName,					propertyName				);		}	}	public void createForeignKey() throws MappingException {		if ( constrained && referencedPropertyName==null) {			//TODO: handle the case of a foreign key to something other than the pk			createForeignKeyOfEntity( ( (EntityType) getType() ).getAssociatedEntityName() );		}	}	public java.util.List getConstraintColumns() {		ArrayList list = new ArrayList();		Iterator iter = identifier.getColumnIterator();		while ( iter.hasNext() ) list.add( iter.next() );		return list;	}	/**	 * Returns the constrained.	 * @return boolean	 */	public boolean isConstrained() {		return constrained;	}	/**	 * Returns the foreignKeyType.	 * @return AssociationType.ForeignKeyType	 */	public ForeignKeyDirection getForeignKeyType() {		return foreignKeyType;	}	/**	 * Returns the identifier.	 * @return Value	 */	public KeyValue getIdentifier() {		return identifier;	}	/**	 * Sets the constrained.	 * @param constrained The constrained to set	 */	public void setConstrained(boolean constrained) {		this.constrained = constrained;	}	/**	 * Sets the foreignKeyType.	 * @param foreignKeyType The foreignKeyType to set	 */	public void setForeignKeyType(ForeignKeyDirection foreignKeyType) {		this.foreignKeyType = foreignKeyType;	}	/**	 * Sets the identifier.	 * @param identifier The identifier to set	 */	public void setIdentifier(KeyValue identifier) {		this.identifier = identifier;	}	public boolean isNullable() {		return !constrained;	}	public Object accept(ValueVisitor visitor) {		return visitor.accept(this);	}	}