set.java

来自「用Java实现的23个常用设计模式源代码」· Java 代码 · 共 62 行

//$Id: Set.java,v 1.6.2.3 2003/11/09 01:46:25 oneovthafew Exp $
package net.sf.hibernate.mapping;

import java.util.Iterator;

import net.sf.hibernate.type.PersistentCollectionType;
import net.sf.hibernate.type.TypeFactory;

/**
 * A set with no nullable element columns. It will have a primary key 
 * consisting of all table columns (ie. key columns + element columns).
 * @author Gavin King
 */
public class Set extends Collection {
	
	/**
	 * Constructor for Set.
	 * @param owner
	 */
	public Set(PersistentClass owner) {
		super(owner);
	}

	public boolean isSet() {
		return true;
	}
	
	public PersistentCollectionType getCollectionType() {
		return isSorted() ? 
			TypeFactory.sortedSet( getRole(), getComparator() ) : 
			TypeFactory.set( getRole() );
	}
	
	public void createPrimaryKey() {
		PrimaryKey pk = new PrimaryKey();
		Iterator iter = getKey().getColumnIterator();
		while ( iter.hasNext() ) {
			pk.addColumn( (Column) iter.next() );
			
		}
		boolean nullable = false;
		iter = getElement().getColumnIterator();
		while ( iter.hasNext() ) {
			Column col = (Column) iter.next();
			//col.setNullable(false);
			if ( col.isNullable() ) nullable=true;
			pk.addColumn(col);
		}
		// Some databases (Postgres) will tolerate nullable
		// column in a primary key others (DB2) won't
		if (!nullable) getCollectionTable().setPrimaryKey(pk);
	}
	
}