RandomRootPage: Do not fail to find page for some random selections; also, do not show 'Redirected from redirected_title' [#719]

140_dbs/src/gplx/dbs/Db_conn.java

@@ -1,31 +1,61 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
-package gplx.dbs; import gplx.*;
-import gplx.core.stores.*; import gplx.dbs.metas.*; import gplx.dbs.engines.*; import gplx.dbs.qrys.*; import gplx.dbs.sys.*; import gplx.dbs.conn_props.*; import gplx.dbs.qrys.bats.*;
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.dbs;
+
+import gplx.Bool_;
+import gplx.Double_;
+import gplx.Err_;
+import gplx.Gfo_log_;
+import gplx.Gfo_usr_dlg;
+import gplx.Gfo_usr_dlg_;
+import gplx.Int_;
+import gplx.Io_url;
+import gplx.List_adp;
+import gplx.List_adp_;
+import gplx.Rls_able;
+import gplx.String_;
+import gplx.core.stores.DataRdr;
+import gplx.core.stores.DataRdr_;
+import gplx.dbs.conn_props.Db_conn_props_mgr;
+import gplx.dbs.engines.Db_engine;
+import gplx.dbs.metas.Dbmeta_idx_fld;
+import gplx.dbs.metas.Dbmeta_tbl_mgr;
+import gplx.dbs.qrys.Db_qry__select_in_tbl;
+import gplx.dbs.qrys.Db_qry_delete;
+import gplx.dbs.qrys.Db_qry_insert;
+import gplx.dbs.qrys.Db_qry_sql;
+import gplx.dbs.qrys.Db_qry_update;
+import gplx.dbs.qrys.bats.Db_batch_mgr;
+import gplx.dbs.sys.Db_sys_mgr;
+import gplx.dbs.wkrs.SqlWkrMgr;
+
 public class Db_conn {
 	private final    List_adp rls_list = List_adp_.New();
 	public Db_conn(Db_engine engine) {
 		this.engine = engine;
 		this.sys_mgr = new Db_sys_mgr(this);
+		this.wkrMgr = new SqlWkrMgr(this);
+		engine.CtorConn(wkrMgr);
 	}
 	public Db_conn_info			Conn_info()				{return engine.Conn_info();}
 	public Db_conn_props_mgr	Props()					{return engine.Props();}
 	public Db_batch_mgr			Batch_mgr()				{return engine.Batch_mgr();}
-	public Db_engine			Engine()				{return engine;} private final    Db_engine engine;
-	public Db_sys_mgr			Sys_mgr()				{return sys_mgr;} private final    Db_sys_mgr sys_mgr;	// autonum and other functions
+	public Db_engine			Engine()				{return engine;} private final Db_engine engine;
+	public Db_sys_mgr			Sys_mgr()				{return sys_mgr;} private final Db_sys_mgr sys_mgr;	// autonum and other functions
+	public SqlWkrMgr            WkrMgr()                {return wkrMgr;} private final SqlWkrMgr wkrMgr;
 	public boolean				Eq(Db_conn comp)		{return String_.Eq(engine.Conn_info().Db_api(), comp.Conn_info().Db_api());}
 	public void					Txn_bgn(String name)	{engine.Txn_bgn(name);}
 	public void					Txn_end()				{engine.Txn_end();}

140_dbs/src/gplx/dbs/Db_crt_.java

@@ -1,18 +1,18 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2017 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
 package gplx.dbs; import gplx.*;
 import gplx.core.criterias.*;
 public class Db_crt_ {
@@ -28,6 +28,7 @@ public class Db_crt_ {
 	public static Criteria_fld New_between		(String key, Comparable lo, Comparable hi)	{return Criteria_fld.new_(key, Criteria_.between_(lo, hi));}
 	public static Criteria_fld New_in			(String key, Object... vals)				{return Criteria_fld.new_(key, Criteria_.in_(vals));}
 	public static Criteria_fld New_like			(String key, String pattern)					{return Criteria_fld.new_(key, Criteria_.like_(pattern));}
+	public static Criteria_fld New_like_not     (String key, String pattern)                    {return Criteria_fld.new_(key, Criteria_.Not(Criteria_.like_(pattern)));}
 
 	public static Criteria eq_many_(String... ary) {
 		Criteria rv = null;

140_dbs/src/gplx/dbs/engines/Db_engine.java

@@ -1,26 +1,44 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
-package gplx.dbs.engines; import gplx.*; import gplx.dbs.*;
-import gplx.core.stores.*; import gplx.dbs.metas.*; import gplx.dbs.sqls.*; import gplx.dbs.conn_props.*; import gplx.dbs.qrys.bats.*;
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.dbs.engines;
+
+import gplx.Gfo_usr_dlg;
+import gplx.Io_url;
+import gplx.core.stores.DataRdr;
+import gplx.dbs.Db_conn;
+import gplx.dbs.Db_conn_info;
+import gplx.dbs.Db_qry;
+import gplx.dbs.Db_rdr;
+import gplx.dbs.Db_stmt;
+import gplx.dbs.Dbmeta_fld_itm;
+import gplx.dbs.Dbmeta_idx_itm;
+import gplx.dbs.Dbmeta_tbl_itm;
+import gplx.dbs.conn_props.Db_conn_props_mgr;
+import gplx.dbs.metas.Dbmeta_tbl_mgr;
+import gplx.dbs.qrys.bats.Db_batch_mgr;
+import gplx.dbs.sqls.Sql_qry_wtr;
+import gplx.dbs.wkrs.SqlWkrMgr;
+
 public interface Db_engine {
 	String				Tid();
 	Db_conn_info		Conn_info();
 	Db_conn_props_mgr	Props();
 	Db_batch_mgr		Batch_mgr();
 	Sql_qry_wtr			Sql_wtr();
+	void                CtorConn(SqlWkrMgr wkrMgr);
 	Db_engine			New_clone(Db_conn_info conn_info);
 	void				Conn_open();
 	void				Conn_term();

140_dbs/src/gplx/dbs/engines/mems/Mem_engine.java

@@ -1,20 +1,22 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
 package gplx.dbs.engines.mems; import gplx.*; import gplx.dbs.*; import gplx.dbs.engines.*;
 import gplx.core.stores.*; import gplx.dbs.metas.*; import gplx.dbs.sqls.*; import gplx.dbs.conn_props.*; import gplx.dbs.qrys.bats.*;
+import gplx.dbs.wkrs.SqlWkrMgr;
+
 public class Mem_engine implements Db_engine {
 	private final    Hash_adp tbl_hash = Hash_adp_.New();
 	Mem_engine(Db_conn_info conn_info) {
@@ -27,6 +29,7 @@ public class Mem_engine implements Db_engine {
 	public Db_batch_mgr			Batch_mgr() {return batch_mgr;} private final    Db_batch_mgr batch_mgr = new Db_batch_mgr();
 	public Mem_exec_select		Qry_runner() {return qry_runner;} private Mem_exec_select qry_runner;
 	public Sql_qry_wtr			Sql_wtr() {return sql_wtr;} private final    Sql_qry_wtr sql_wtr = Sql_qry_wtr_.New__basic();
+	@Override public void       CtorConn(SqlWkrMgr wkrMgr) {}
 	public Db_engine			New_clone(Db_conn_info conn_info) {return new Mem_engine(conn_info);}
 	public Db_stmt				Stmt_by_qry(Db_qry qry) {return new Mem_stmt(this, qry);}
 	public Mem_tbl				Tbls__get(String name)	{return (Mem_tbl)tbl_hash.Get_by(name);}

140_dbs/src/gplx/dbs/engines/mysql/Mysql_engine.java

@@ -1,24 +1,27 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
 package gplx.dbs.engines.mysql; import gplx.*; import gplx.dbs.*; import gplx.dbs.engines.*;
 import gplx.core.stores.*; import gplx.dbs.engines.*; import gplx.dbs.sqls.*; import gplx.dbs.metas.*;
-import java.sql.*; 
-public class Mysql_engine extends Db_engine_sql_base {
+import gplx.dbs.wkrs.SqlWkrMgr;
+
+import java.sql.*;
+public class Mysql_engine extends Db_engine_sql_base {
 	@Override public String Tid() {return Mysql_conn_info.Tid_const;}
 	@Override public Sql_qry_wtr	Sql_wtr() {return Sql_qry_wtr_.New__mysql();}
+	@Override public void CtorConn(SqlWkrMgr wkrMgr) {}
 	@Override public Db_engine New_clone(Db_conn_info connectInfo) {
 		Mysql_engine rv = new Mysql_engine();
 		rv.Ctor(connectInfo);
@@ -33,7 +36,7 @@ public class Mysql_engine extends Db_engine_sql_base {
 	}
 		public static final    Mysql_engine Instance = new Mysql_engine(); Mysql_engine() {}
 }
-class Mysql_rdr extends Db_data_rdr {
+class Mysql_rdr extends Db_data_rdr {
 		//PATCH:MYSQL:byte actually returned as int by Jdbc ResultSet (or MYSQL impmentation); convert to byte 
 	@Override public byte ReadByte(String key) {return ReadByteOr(key, Byte.MAX_VALUE);}
 	@Override public byte ReadByteOr(String key, byte or) {

140_dbs/src/gplx/dbs/engines/noops/Noop_engine.java

@@ -1,26 +1,29 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
  package gplx.dbs.engines.noops; import gplx.*; import gplx.dbs.*; import gplx.dbs.engines.*;
 import gplx.core.stores.*; import gplx.dbs.metas.*; import gplx.dbs.sqls.*; import gplx.dbs.conn_props.*; import gplx.dbs.qrys.bats.*;
+import gplx.dbs.wkrs.SqlWkrMgr;
+
 public class Noop_engine implements Db_engine {
 	public String				Tid() {return Noop_conn_info.Tid_const;}
 	public Db_conn_info			Conn_info() {return Db_conn_info_.Null;}
 	public Db_conn_props_mgr	Props() {return props;} private final    Db_conn_props_mgr props = new Db_conn_props_mgr();
 	public Db_batch_mgr			Batch_mgr() {return batch_mgr;} private final    Db_batch_mgr batch_mgr = new Db_batch_mgr();
 	public Sql_qry_wtr			Sql_wtr() {return sql_wtr;} private final    Sql_qry_wtr sql_wtr = Sql_qry_wtr_.New__basic();
+	@Override public void       CtorConn(SqlWkrMgr wkrMgr) {}
 	public void					Conn_open() {}
 	public void					Conn_term() {}
 	public Db_engine			New_clone(Db_conn_info url) {return this;}

140_dbs/src/gplx/dbs/engines/postgres/Postgres_engine.java

@@ -1,24 +1,29 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
 package gplx.dbs.engines.postgres; import gplx.*; import gplx.dbs.*; import gplx.dbs.engines.*;
 import gplx.core.stores.*; import gplx.dbs.engines.*; import gplx.dbs.sqls.*; import gplx.dbs.metas.*;
-import java.sql.*; 
+import gplx.dbs.wkrs.SqlWkrMgr;
+
+import java.sql.Connection;
+import java.sql.ResultSet;
+
 public class Postgres_engine extends Db_engine_sql_base {
 	@Override public String Tid() {return Postgres_conn_info.Tid_const;}
 	@Override public Sql_qry_wtr	Sql_wtr() {return Sql_qry_wtr_.New__mysql();}
+	@Override public void CtorConn(SqlWkrMgr wkrMgr) {}
 	@Override public Db_engine New_clone(Db_conn_info connectInfo) {
 		Postgres_engine rv = new Postgres_engine();
 		rv.Ctor(connectInfo);

140_dbs/src/gplx/dbs/engines/sqlite/Sqlite_engine.java

@@ -1,18 +1,18 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
 package gplx.dbs.engines.sqlite; import gplx.*; import gplx.dbs.*; import gplx.dbs.engines.*;
 import java.sql.*; 
 import gplx.core.stores.*; import gplx.dbs.engines.*; import gplx.dbs.engines.sqlite.*; import gplx.dbs.metas.*; import gplx.dbs.sqls.*;
@@ -21,6 +21,8 @@ import gplx.core.consoles.Console_adp_;
 import gplx.core.consoles.Console_adp__sys;
 import gplx.core.ios.IoItmFil;
 
+import gplx.dbs.wkrs.SqlWkrMgr;
+import gplx.dbs.wkrs.randoms.SqliteRandomWkr;
 import org.sqlite.SQLiteConnection;
 public class Sqlite_engine extends Db_engine_sql_base {
 	private final    Sqlite_txn_mgr txn_mgr; private final    Sqlite_schema_mgr schema_mgr;
@@ -30,6 +32,10 @@ public class Sqlite_engine extends Db_engine_sql_base {
 	}
 	@Override public String Tid() {return Sqlite_conn_info.Key_const;}
 	@Override public gplx.dbs.sqls.Sql_qry_wtr Sql_wtr() {return Sql_qry_wtr_.New__sqlite();}
+	public void CtorConn(SqlWkrMgr wkrMgr) {
+		wkrMgr.Set(new SqliteRandomWkr());
+	}
+
 	@Override public Db_engine New_clone(Db_conn_info connectInfo) {
 		Sqlite_engine rv = new Sqlite_engine();
 		rv.Ctor(connectInfo);
@@ -89,7 +95,7 @@ public class Sqlite_engine extends Db_engine_sql_base {
 		catch (SQLException e) {Gfo_usr_dlg_.Instance.Warn_many("", "", "failed to set busy timeout; err=~{0}", Err_.Message_gplx_log(e));}
 		return rv;
 	}
-		public static final    Sqlite_engine Instance = new Sqlite_engine();
+	public static final    Sqlite_engine Instance = new Sqlite_engine();
 }
 class Db_rdr__sqlite extends Db_rdr__basic {	@Override public byte Read_byte(String k)		{try {return (byte)Int_.Cast(rdr.getObject(k));} catch (Exception e) {throw Err_.new_exc(e, "db", "read failed", "k", k, "type", Byte_.Cls_val_name);}} 
 		@Override public boolean Read_bool_by_byte(String k) {

140_dbs/src/gplx/dbs/engines/tdbs/TdbEngine.java

@@ -1,20 +1,22 @@
-/*
-XOWA: the XOWA Offline Wiki Application
-Copyright (C) 2012-2017 gnosygnu@gmail.com
-
-XOWA is licensed under the terms of the General Public License (GPL) Version 3,
-or alternatively under the terms of the Apache License Version 2.0.
-
-You may use XOWA according to either of these licenses as is most appropriate
-for your project on a case-by-case basis.
-
-The terms of each license can be found in the source code repository:
-
-GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
-Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
-*/
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
 package gplx.dbs.engines.tdbs; import gplx.*; import gplx.dbs.*; import gplx.dbs.engines.*;
 import gplx.core.stores.*; import gplx.dbs.metas.*; import gplx.dbs.conn_props.*; import gplx.dbs.qrys.*; import gplx.dbs.sqls.*; import gplx.dbs.qrys.bats.*;
+import gplx.dbs.wkrs.SqlWkrMgr;
+
 public class TdbEngine implements Db_engine {
 	public String Tid() {return Tdb_conn_info.Tid_const;}
 	public Db_conn_info			Conn_info() {return conn_info;} private Db_conn_info conn_info;
@@ -22,6 +24,7 @@ public class TdbEngine implements Db_engine {
 	public Db_batch_mgr			Batch_mgr() {return batch_mgr;} private final    Db_batch_mgr batch_mgr = new Db_batch_mgr();
 	public Sql_qry_wtr			Sql_wtr() {return sql_wtr;} private final    Sql_qry_wtr sql_wtr = Sql_qry_wtr_.New__basic();
 	public TdbDatabase Db() {return db;} TdbDatabase db;
+	@Override public void CtorConn(SqlWkrMgr wkrMgr) {}
 	public void Conn_open() {
 		Tdb_conn_info tdb_url = (Tdb_conn_info)conn_info;
 		String url_str = tdb_url.Server();

140_dbs/src/gplx/dbs/wkrs/SqlWkr.java

@@ -0,0 +1,20 @@
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.dbs.wkrs;
+
+public interface SqlWkr {
+    String Key();
+}

140_dbs/src/gplx/dbs/wkrs/SqlWkrMgr.java

@@ -0,0 +1,43 @@
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.dbs.wkrs;
+
+import gplx.dbs.Db_conn;
+import gplx.dbs.wkrs.randoms.SqlRandomWkr;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class SqlWkrMgr {
+    private final Map<String, SqlWkr> map = new HashMap<>();
+    private final Db_conn conn;
+    public SqlWkrMgr(Db_conn conn) {
+        this.conn = conn;
+    }
+    public SqlWkr Get(String key) {
+        return map.get(key);
+    }
+    public void Set(SqlWkr wkr) {
+        map.put(wkr.Key(), wkr);
+    }
+
+    public Object ExecRandomObj(String select, String from, String where) {
+		SqlRandomWkr wkr = (SqlRandomWkr)map.get(SqlWkrMgr.WKR_RANDOM);
+		return wkr.SelectRandomRow(conn, select, from, where)[0];
+    }
+
+    public static final String WKR_RANDOM = "random";
+}

140_dbs/src/gplx/dbs/wkrs/randoms/SqlRandomWkr.java

@@ -0,0 +1,23 @@
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.dbs.wkrs.randoms;
+
+import gplx.dbs.Db_conn;
+import gplx.dbs.wkrs.SqlWkr;
+
+public interface SqlRandomWkr extends SqlWkr {
+    Object[] SelectRandomRow(Db_conn conn, String select, String from, String where);
+}

140_dbs/src/gplx/dbs/wkrs/randoms/SqliteRandomWkr.java

@@ -0,0 +1,60 @@
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.dbs.wkrs.randoms;
+
+import gplx.RandomAdp_;
+import gplx.dbs.Db_conn;
+import gplx.dbs.Db_rdr;
+import gplx.dbs.Db_rdr_;
+import gplx.dbs.wkrs.SqlWkrMgr;
+
+public class SqliteRandomWkr implements SqlRandomWkr {
+    @Override public String Key() {return SqlWkrMgr.WKR_RANDOM;}
+
+    // NOTE: selects only 1 random row to simplify method signature
+    // * uses COUNT, LIMIT, OFFSET, so should also work for MySQL
+    // * to return many rows, look at https://stackoverflow.com/questions/4114940/select-random-rows-in-sqlite
+    // EX: SELECT * FROM table WHERE id IN (SELECT id FROM table ORDER BY RANDOM() LIMIT x)
+    // Also, note that SQLite does not support TYPE_FORWARD_ONLY so can't jump back and forth thru ResultSet
+    @Override public Object[] SelectRandomRow(Db_conn conn, String select, String from, String where) {
+        Db_rdr rdr = Db_rdr_.Empty;
+        try {
+            String sqlSuffix = ("FROM " + from + " WHERE " + where);
+
+            // get rowCount of resultSet
+            rdr = conn.Stmt_sql("SELECT COUNT(*) AS RowCount " + sqlSuffix).Exec_select__rls_auto();
+            int rowCount = rdr.Read_int("RowCount");
+
+            // get random row
+            int random = RandomAdp_.new_().Next(rowCount);
+            rdr = conn.Stmt_sql("SELECT " + select + " " + sqlSuffix + " LIMIT 1 OFFSET " + random).Exec_select__rls_auto();
+
+            // return result
+            int fldsLen = rdr.Fld_len();
+            Object[] rv = new Object[fldsLen];
+            for (int i = 0; i < fldsLen; i++) {
+                rv[i] = rdr.Read_at(i);
+            }
+            return rv;
+        }
+        catch (Exception exc) { // for debugging; should log
+            throw exc;
+        }
+        finally {
+            rdr.Rls();
+        }
+    }
+}

140_dbs/src/gplx/dbs/wkrs/randoms/TestRandomWkr.java

@@ -0,0 +1,51 @@
+/*
+XOWA: the XOWA Offline Wiki Application
+Copyright (C) 2012-2020 gnosygnu@gmail.com
+
+XOWA is licensed under the terms of the General Public License (GPL) Version 3,
+or alternatively under the terms of the Apache License Version 2.0.
+
+You may use XOWA according to either of these licenses as is most appropriate
+for your project on a case-by-case basis.
+
+The terms of each license can be found in the source code repository:
+
+GPLv3 License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-GPLv3.txt
+Apache License: https://github.com/gnosygnu/xowa/blob/master/LICENSE-APACHE2.txt
+*/
+package gplx.dbs.wkrs.randoms;
+
+import gplx.dbs.Db_conn;
+import gplx.dbs.wkrs.SqlWkrMgr;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class TestRandomWkr implements SqlRandomWkr {
+    private final List<Object[]> list = new ArrayList<>();
+    private int index = 0;
+    public void AddRow(Object... ary) {
+        list.add(ary);
+    }
+    public void Clear() {
+        list.clear();
+        index = 0;
+    }
+    public String SelectRandomRowSelect() {return selectRandomRowSelect;} private String selectRandomRowSelect;
+    public String SelectRandomRowFrom() {return selectRandomRowFrom;} private String selectRandomRowFrom;
+    public String SelectRandomRowWhere() {return selectRandomRowWhere;} private String selectRandomRowWhere;
+
+    @Override public String Key() {return SqlWkrMgr.WKR_RANDOM;}
+    @Override public Object[] SelectRandomRow(Db_conn conn, String select, String from, String where) {
+        this.selectRandomRowSelect = select;
+        this.selectRandomRowFrom = from;
+        this.selectRandomRowWhere = where;
+        return list.get(index++);
+    }
+
+    public static TestRandomWkr New(Db_conn conn) {
+        TestRandomWkr wkr = new TestRandomWkr();
+        conn.WkrMgr().Set(wkr);
+        return wkr;
+    }
+}