@Override
public String getQuery(CloudataConf conf) {
String query = "SELECT ";
String columnQuery = "";
for (ColumnElement eachElement : selectColumns) {
columnQuery += eachElement.getQuery(conf) + ", ";
}
if (columnQuery.length() > 1) {
columnQuery = columnQuery.substring(0, columnQuery.length() - 2);
}
query += columnQuery;
String fromQuery = "";
for (FromElement eachElement : fromTables) {
fromQuery += eachElement.getQuery(conf) + ", ";
}
if (fromQuery.length() > 1) {
fromQuery = fromQuery.substring(0, fromQuery.length() - 2);
}
query += " FROM " + fromQuery;
if (where != null) {
query += " WHERE " + where.getQuery(conf);
}
return query;
}
@Override
public ExecStatus execute(CloudataConf conf) {
ExecStatus status = new ExecStatus();
try {
// 현재 버전에서는 from 절에 subquery나 여러개의 테이블이 나타나는 것을 지원하지 않음
if (fromTables.size() > 1) {
throw new IOException("Not support multi tables");
}
String tableName = fromTables.get(0).getTableName();
CTable ctable = CTable.openTable(conf, tableName);
if (ctable == null) {
throw new IOException("No table [" + tableName + "]");
}
RowFilter rowFilter = new RowFilter();
for (ColumnElement eachElement : selectColumns) {
List<String> columnNames = eachElement.getColumnNames(ctable);
for (String eachColumn : columnNames) {
CellFilter cellFilter = new CellFilter(eachColumn);
rowFilter.addCellFilter(cellFilter);
}
}
if (where != null) {
where.initFilter(rowFilter);
Row[] rows = ctable.gets(rowFilter);
status.setRowIterator(new RowArrayIterator(ctable, rows, rowFilter.getColumns()));
int rowCount = rows == null ? 0 : rows.length;
status.setMessage(rowCount + " selected.");
} else {
TableScanner scanner = ScannerFactory.openScanner(ctable, rowFilter);
status.setRowIterator(new RowScannerIterator(ctable, scanner, rowFilter.getColumns()));
}
} catch (IOException e) {
status.setException(e);
}
return status;
}