void addIndex(IndexType type,List<String> columnNames){
  IndexDefinition index=new IndexDefinition();
  index.indexName=tableName + "_" + indexes.size();
  index.columnNames=New.arrayList(columnNames);
  index.type=type;
  indexes.add(index);
}

void addIndex ( IndexType type , List < String > columnNames ) { IndexDefinition index = new IndexDefinition ( ) ; index . indexName = tableName + "_" + indexes . size ( ) ; index . columnNames = New . arrayList ( columnNames ) ; index . type = type ; indexes . add ( index ) ; }
defines an index with the specified column names .
