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114 lines
4.9 KiB
114 lines
4.9 KiB
/*
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XOWA: the XOWA Offline Wiki Application
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Copyright (C) 2012 gnosygnu@gmail.com
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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package gplx.dbs.engines.tdbs; import gplx.*; import gplx.dbs.*; import gplx.dbs.engines.*;
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import gplx.core.criterias.*; import gplx.core.gfo_ndes.*; import gplx.dbs.qrys.*; import gplx.dbs.sqls.*; import gplx.dbs.sqls.itms.*;
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import gplx.core.lists.*; /*ComparerAble*/ import gplx.core.stores.*; /*GfoNdeRdr*/
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class TdbSelectWkr implements Db_qryWkr {
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public Object Exec(Db_engine engineObj, Db_qry cmdObj) {
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TdbEngine engine = TdbEngine.cast(engineObj); Db_qry__select_cmd cmd = (Db_qry__select_cmd)cmdObj;
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if (cmd.From().Tbls.Count() > 1) throw Err_.new_("gplx.tdbs", "joins not supported for tdbs", "sql", cmd.To_sql__exec(engineObj.Sql_wtr()));
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TdbTable tbl = engine.FetchTbl(cmd.From().Base_tbl.Name);
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GfoNdeList rv = (cmd.Where_itm() == Sql_where_itm.Where__null && cmd.Limit() == Db_qry__select_cmd.Limit__disabled) ? rv = tbl.Rows() : FilterRecords(tbl, cmd.Where_itm().Root, cmd.Limit());
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if (cmd.GroupBy() != null)
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rv = TdbGroupByWkr.GroupByExec(cmd, rv, tbl);
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if (cmd.Order() != null) { // don't use null pattern here; if null ORDER BY, then don't call .Sort on GfoNdeList
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ComparerAble comparer = Sql_order_fld_sorter.new_(cmd.Order().Flds);
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rv.Sort_by(comparer);
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}
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return GfoNdeRdr_.peers_(rv, false);
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}
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GfoNdeList FilterRecords(TdbTable tbl, Criteria crt, int limit) {
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GfoNdeList rv = GfoNdeList_.new_();
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int count = 0;
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for (int i = 0; i < tbl.Rows().Count(); i++) {
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GfoNde row = (GfoNde)tbl.Rows().FetchAt_asGfoNde(i);
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if (crt.Matches(row)) rv.Add(row);
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++count;
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if (count == limit) break;
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}
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return rv;
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}
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public static GfoFldList To_GfoFldLst(TdbTable tbl, Sql_select_fld_list flds) {
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GfoFldList rv = GfoFldList_.new_();
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int len = flds.Len();
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for (int i = 0; i < len; ++i) {
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Sql_select_fld selectFld = flds.Get_at(i);
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GfoFld fld = tbl.Flds().FetchOrNull(selectFld.Fld);
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if (fld == null) throw Err_.new_wo_type("fld not found in tbl", "fldName", selectFld.Fld, "tblName", tbl.Name(), "tblFlds", tbl.Flds().To_str());
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if (rv.Has(selectFld.Alias)) throw Err_.new_wo_type("alias is not unique", "fldName", selectFld.Fld, "flds", rv.To_str());
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selectFld.GroupBy_type(fld.Type());
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rv.Add(selectFld.Alias, selectFld.Val_type());
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}
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return rv;
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}
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public static final TdbSelectWkr Instance = new TdbSelectWkr(); TdbSelectWkr() {}
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}
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class TdbGroupByWkr {
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public static GfoNdeList GroupByExec(Db_qry__select_cmd select, GfoNdeList selectRows, TdbTable tbl) {
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GfoNdeList rv = GfoNdeList_.new_();
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Ordered_hash groupByHash = Ordered_hash_.New();
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List_adp groupByFlds = select.GroupBy().Flds();
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GfoFldList selectFldsForNewRow = TdbSelectWkr.To_GfoFldLst(tbl, select.Cols().Flds);
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Sql_select_fld_list selectFlds = select.Cols().Flds;
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for (int rowIdx = 0; rowIdx < selectRows.Count(); rowIdx++) {
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GfoNde selectRow = selectRows.FetchAt_asGfoNde(rowIdx);
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GfoNde groupByRow = FindOrNew(selectFldsForNewRow, groupByFlds, selectRow, groupByHash, rv);
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int len = selectFlds.Len();
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for (int i = 0; i < len; ++i) {
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Sql_select_fld selectFld = selectFlds.Get_at(i);
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Object val = groupByRow.Read(selectFld.Alias); // groupByRow is keyed by Alias; EX: Count(Id) AS CountOf
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groupByRow.WriteAt(i, selectFld.GroupBy_eval(val, selectRow.Read(selectFld.Fld), selectFld.Val_type()));
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}
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}
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return rv;
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}
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static GfoNde FindOrNew(GfoFldList selectFldsForNewRow, List_adp groupByFlds, GfoNde selectRow, Ordered_hash groupByRows, GfoNdeList rslt) {
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int len = groupByFlds.Count();
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Ordered_hash curHash = groupByRows;
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GfoNde rv = null;
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for (int i = 0; i < len; i++) {
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String fld = (String)groupByFlds.Get_at(i);
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boolean last = i == len - 1;
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Object val = selectRow.Read(fld);
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Object o = curHash.Get_by(val);
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if (last) {
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if (o == null) {
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Object[] valAry = new Object[selectFldsForNewRow.Count()];
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rv = GfoNde_.vals_(selectFldsForNewRow, valAry);
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curHash.Add(val, rv);
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rslt.Add(rv);
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}
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else
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rv = GfoNde_.as_(o);
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}
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else {
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if (o == null) {
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Ordered_hash nextHash = Ordered_hash_.New();
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curHash.Add(val, nextHash);
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curHash = nextHash;
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}
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else {
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curHash = (Ordered_hash)o;
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}
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}
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}
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return rv;
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}
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}
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