public  void addReferencedColumns(Iterator referencedColumnsIterator) 
{
		while ( referencedColumnsIterator.hasNext() ) {
			Selectable col = (Selectable) referencedColumnsIterator.next();
			if ( !col.isFormula() ) addReferencedColumn( (Column) col );
		}
}

 public  void alignColumns() 
{
		if ( isReferenceToPrimaryKey() ) alignColumns(referencedTable);
}

Validates that columnspan of the foreignkey and the primarykey is the same. Furthermore it aligns the length of the underlying tables columns.

 public List getReferencedColumns() 
{
		return referencedColumns;
}

Returns the referenced columns if the foreignkey does not refer to the primary key

 public String getReferencedEntityName() 
{
		return referencedEntityName;
}

 public Table getReferencedTable() 
{
		return referencedTable;
}

 public boolean isCascadeDeleteEnabled() 
{
		return cascadeDeleteEnabled;
}

 public boolean isPhysicalConstraint() 
{
		return referencedTable.isPhysicalTable() && 
				getTable().isPhysicalTable() && 
				!referencedTable.hasDenormalizedTables();
}

 public boolean isReferenceToPrimaryKey() 
{
		return referencedColumns.isEmpty();
}

Does this foreignkey reference the primary key of the reference table

 public  void setCascadeDeleteEnabled(boolean cascadeDeleteEnabled) 
{
		this.cascadeDeleteEnabled = cascadeDeleteEnabled;
}

 public  void setReferencedEntityName(String referencedEntityName) 
{
		this.referencedEntityName = referencedEntityName;
}

 public  void setReferencedTable(Table referencedTable) throws MappingException 
{
		//if( isReferenceToPrimaryKey() ) alignColumns(referencedTable); // TODO: possibly remove to allow more piecemal building of a foreignkey.  
		this.referencedTable = referencedTable;
}

 public String sqlConstraintString(Dialect dialect,
    String constraintName,
    String defaultCatalog,
    String defaultSchema) 
{
    
		String[] cols = new String[ getColumnSpan() ];
		String[] refcols = new String[ getColumnSpan() ];
		int i=0;
		Iterator refiter = null;
		if(isReferenceToPrimaryKey() ) {
			refiter = referencedTable.getPrimaryKey().getColumnIterator();
		} 
		else {
			refiter = referencedColumns.iterator();
		}
		Iterator iter = getColumnIterator();
		while ( iter.hasNext() ) {
			cols[i] = ( (Column) iter.next() ).getQuotedName(dialect);
			refcols[i] = ( (Column) refiter.next() ).getQuotedName(dialect);
			i++;
		}
		String result = dialect.getAddForeignKeyConstraintString(
			constraintName, cols, referencedTable.getQualifiedName(dialect, defaultCatalog, defaultSchema), refcols, isReferenceToPrimaryKey()
		);
		return cascadeDeleteEnabled && dialect.supportsCascadeDelete() ? 
			result + " on delete cascade" : 
			result;
}

 public String sqlDropString(Dialect dialect,
    String defaultCatalog,
    String defaultSchema) 
{
		return "alter table " + 
			getTable().getQualifiedName(dialect, defaultCatalog, defaultSchema) + 
			dialect.getDropForeignKeyString() + 
			getName();
}

 public String toString() 
{
		if(!isReferenceToPrimaryKey() ) {
			StringBuffer result = new StringBuffer(getClass().getName() + '(" + getTable().getName() + getColumns() );
			result.append( " ref-columns:" + '(" + getReferencedColumns() );
			result.append( ") as " + getName() );
			return result.toString();
		} 
		else {
			return super.toString();
		}
}