querysqlexecuter.java

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package com.whatratimes.dbms;

import java.util.Enumeration;

/**
 * Created by IntelliJ IDEA.
 * User: Tao
 * Date: May 10, 2003
 * Time: 10:34:24 AM
 */
public class QuerySQLExecuter extends SQLExecuter
{
    private boolean isDistinct = false;
    private StringBuffer orderBy;
    private StringBuffer groupBy;
    private StringBuffer columns;

    public QuerySQLExecuter()
    {
        super();
    }

    public void setRowLimit(int skip, int rows)
    {
        super.setRowLimit(skip, rows);
    }

    public void appendGroupBy ( String column_name )
    {
        if ( groupBy == null )
        {
            groupBy = new StringBuffer();
        } else
        {
            groupBy.append(", ");
        }

        groupBy.append(column_name);

    }
    private void appendOrderBy ( String column_name )
    {
        if ( orderBy == null )
        {
            orderBy = new StringBuffer();
        } else
        {
            orderBy.append(", ");
        }

        orderBy.append(column_name);
        orderBy.append(" ");

    }

    public void appendOrderByASC ( String column_name )
    {
        appendOrderBy( column_name );
        orderBy.append("ASC");
    }

    public void appendOrderByDESC ( String column_name )
    {
        appendOrderBy( column_name );

        orderBy.append("DESC");
    }

    public Object[] executeQuery()
    {
        return super.executeQuery();
    }

    public void setWhereConditionOR()
    {
        super.setWhereConditionOR();
    }

    public void appendWhereClause(String where_clause)
    {
        super.appendWhereClause(where_clause);
    }

    public void appendWhereCondition(String column_name, String operator, Object value)
    {
        super.appendWhereCondition(column_name, operator, value);
    }

    public void clearAllColumns ()
    {
        columns = null;
    }

    public void appendColumn (String column_name, String alias )
    {
        if ( columns == null )
        {
            columns = new StringBuffer();
        } else
        {
            columns.append(", ");
        }

        columns.append(column_name);
        columns.append(" ");
        columns.append(alias);
    }

    public void appendColumn (String column_name)
    {
        appendColumn(column_name, "");
    }

    public void setDistinct ()
    {
        isDistinct = true;

    }

    private StringBuffer getColumnString()
    {

        StringBuffer column_string = new StringBuffer();

        Enumeration enu = values.keys();

        while ( enu.hasMoreElements())
        {
            Object key = enu.nextElement();

            column_string.append( key.toString());

            Object alias = values.get(key);

            if ( !key.equals(alias))
            {
                column_string.append(" ");
                column_string.append(alias.toString());
            }
        }

        return column_string;
    }

    public String getSQL()
    {
        StringBuffer mySQL = new StringBuffer( " SELECT ");

        if ( isDistinct )
        {
            mySQL.append(" DISTINCT ");
        }

        mySQL.append(columns);
        mySQL.append(getTableString());
        mySQL.append(getWhereClause());

        if ( orderBy != null )
        {
            mySQL.append(" ORDER BY ");
            mySQL.append(orderBy);
        }

        if ( groupBy != null )
        {
            mySQL.append(" GROUP BY ");
            mySQL.append(groupBy);
        }

        return mySQL.toString();
    }
}