Sql_select_fld_func.java

/*
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.sqls.itms; import gplx.*; import gplx.dbs.*; import gplx.dbs.sqls.*;
import gplx.core.type_xtns.*;
abstract class Sql_select_fld_func extends Sql_select_fld {		public Sql_select_fld_func(String tbl, String fld, String alias) {super(tbl, fld, alias);}
	public abstract String XtoSql_functionName();
	@Override public String To_fld_sql() {
		return String_.Format("{0}({1}) AS {2}", XtoSql_functionName(), Fld, Alias);
	}
}
class Sql_select_fld_count extends Sql_select_fld_func {			public Sql_select_fld_count(String tbl, String fld, String alias) {super(tbl, fld, alias);}
	@Override public String XtoSql_functionName() {return "COUNT";}
	@Override public void GroupBy_type(ClassXtn type) {this.Val_type_(IntClassXtn.Instance);}
	@Override public Object GroupBy_eval(Object groupByVal, Object curVal, ClassXtn type) {
		if (groupByVal == null) return 1;
		return Int_.cast(groupByVal) + 1;
	}
}
class Sql_select_fld_sum extends Sql_select_fld_func {			public Sql_select_fld_sum(String tbl, String fld, String alias) {super(tbl, fld, alias);}
	@Override public String XtoSql_functionName() {return "SUM";}
	@Override public void GroupBy_type(ClassXtn type) {this.Val_type_(IntClassXtn.Instance);}
	@Override public Object GroupBy_eval(Object groupByVal, Object curVal, ClassXtn type) {
		if (groupByVal == null) return Int_.cast(curVal);
		return Int_.cast(groupByVal) + Int_.cast(curVal);
	}
}
class Sql_select_fld_minMax extends Sql_select_fld_func {		private final int compareType;
	public Sql_select_fld_minMax(int compareType, String tbl, String fld, String alias) {super(tbl, fld, alias);
		this.compareType = compareType;
	}
	@Override public String XtoSql_functionName() {return compareType == CompareAble_.Less ? "MIN" : "MAX";}
	@Override public Object GroupBy_eval(Object groupByVal, Object curVal, ClassXtn type) {
		if (groupByVal == null) return curVal;
		int compareVal = CompareAble_.Compare_obj(curVal, groupByVal);
		return compareVal * compareType > 0 ? curVal : groupByVal;
	}
}