public SelectFragment() 
{

}

 public SelectFragment addColumn(String columnName) 
{
		addColumn(null, columnName);
		return this;
}

 public SelectFragment addColumn(String tableAlias,
    String columnName) 
{
		return addColumn(tableAlias, columnName, columnName);
}

 public SelectFragment addColumn(String tableAlias,
    String columnName,
    String columnAlias) 
{
		columns.add( StringHelper.qualify(tableAlias, columnName) );
		//columns.add(columnName);
		//aliases.add(tableAlias);
		columnAliases.add(columnAlias);
		return this;
}

 public SelectFragment addColumns(String[] columnNames) 
{
		for (int i=0; i< columnNames.length; i++) addColumn( columnNames[i] );
		return this;
}

 public SelectFragment addColumns(String tableAlias,
    String[] columnNames) 
{
		for (int i=0; i< columnNames.length; i++) addColumn( tableAlias, columnNames[i] );
		return this;
}

 public SelectFragment addColumns(String tableAlias,
    String[] columnNames,
    String[] columnAliases) 
{
		for (int i=0; i< columnNames.length; i++) {
			if ( columnNames[i]!=null ) addColumn( tableAlias, columnNames[i], columnAliases[i] );
		}
		return this;
}

 public SelectFragment addFormula(String tableAlias,
    String formula,
    String formulaAlias) 
{
		columns.add( StringHelper.replace(formula, Template.TEMPLATE, tableAlias) );
		columnAliases.add(formulaAlias);
		return this;
}

 public SelectFragment addFormulas(String tableAlias,
    String[] formulas,
    String[] formulaAliases) 
{
		for ( int i=0; i< formulas.length; i++ ) {
			if ( formulas[i]!=null ) addFormula( tableAlias, formulas[i], formulaAliases[i] );
		}
		return this;
}

 public SelectFragment setExtraSelectList(String extraSelectList) 
{
		this.extraSelectList = extraSelectList;
		return this;
}

 public SelectFragment setExtraSelectList(CaseFragment caseFragment,
    String fragmentAlias) 
{
		setExtraSelectList( caseFragment.setReturnColumnName(fragmentAlias, suffix).toFragmentString() );
		return this;
}

 public SelectFragment setSuffix(String suffix) 
{
		this.suffix = suffix;
		return this;
}

 public SelectFragment setUsedAliases(String[] aliases) 
{
		usedAliases = aliases;
		return this;
}

 public String toFragmentString() 
{
		StringBuffer buf = new StringBuffer( columns.size() * 10 );
		Iterator iter = columns.iterator();
		Iterator columnAliasIter = columnAliases.iterator();
		//HashMap columnsUnique = new HashMap();
		HashSet columnsUnique = new HashSet();
		if (usedAliases!=null) columnsUnique.addAll( Arrays.asList(usedAliases) );
		while ( iter.hasNext() ) {
			String column = (String) iter.next();
			String columnAlias = (String) columnAliasIter.next();
			//TODO: eventually put this back in, once we think all is fixed
			//Object otherAlias = columnsUnique.put(qualifiedColumn, columnAlias);
			/*if ( otherAlias!=null && !columnAlias.equals(otherAlias) ) {
				throw new AssertionFailure("bug in Hibernate SQL alias generation");
			}*/
			if ( columnsUnique.add(columnAlias) ) {
				buf.append(", ")
					.append(column)
					.append(" as ");
				if (suffix==null) {
					buf.append(columnAlias);
				}
				else {
					buf.append( new Alias(suffix).toAliasString(columnAlias) );
				}
			}
		}
		if (extraSelectList!=null) {
			buf.append(", ")
				.append(extraSelectList);
		}
		return buf.toString();
}