package bradleyross.j2ee.servlets;
import java.sql.ResultSet;
import java.sql.SQLException;
import bradleyross.library.database.DatabaseProperties;
import bradleyross.library.helpers.StringHelpers;
/**
 * Generate the code for a pull-down list to be placed
 * in a web page.
 * 
 * @author Bradley Ross
 *
 */
public abstract class PulldownList 
{
        /**
         * Object containing database connection properties.
         * 
         * <p>The value should be set by the constructor.</p>
         */
        protected DatabaseProperties data;
        /**
         * Creates result set that is used to generate select tag.
         * @param selector Option value that can be used to control generation of tag
         * @return Result set
         */
        protected abstract ResultSet buildResultSet(String selector);
        /**
         * Used to generate initial option in select tag.
         * @return HTML code for initial option tag
         */
        protected String initialOption()
        {
                return new String();
        }
        /**
         * Generate the HTML code for a SELECT tag
         * that allows a single value to be selected.
         * 
         * @param name Name attribute for SELECT tag
         * @param value Existing value for selector
         * @param selector Option to be used in creating HTML code
         * @param attributes Code for additional attributes for SELECT tag
         * @return HTML code
         */
        public String singleRequest(String name, String value, String selector, String attributes) throws SQLException
        {
                StringBuffer working = new StringBuffer("<select name=\"" + name + "\" ");
                if (attributes != null)
                {
                        working.append(attributes);
                }
                working.append(" >");
                working.append(initialOption());
                ResultSet rs = buildResultSet(selector);
                while (rs.next())
                {
                        String temp = getValue(rs, selector);
                        String text = getText(rs, selector);
                        working.append("<option value=\"" + StringHelpers.escapeHTML(temp) + "\"");
        
                        if (temp.equalsIgnoreCase(value))
                        {
                                working.append(" selected=\"selected\" ");
                        }               
                        working.append(">");
                        if (text != null)
                        {
                                working.append(StringHelpers.escapeHTML(text));
                        }
                        working.append("</option>");
                }
                working.append("</select>");
                return new String(working);
        }
        /**
         * Generate the HTML code for a SELECT tag that
         * allows multiple values to be selected.
         * 
         * @param name Name attribute for SELECT tag
         * @param values Existing values for items in tag
         * @param selector Option to be used in creating HTML code
         * @param attributes Additional attributes for SELECT tag
         * @return HTML code
         */
        public String multipleRequest(String name, String values[], String selector, String attributes) throws SQLException
        {
                StringBuffer working = new StringBuffer("<select multiple=\"multiple\" name=\"" + name + "\" ");
                if (attributes != null)
                {
                        working.append(attributes);
                }
                working.append(" >");
                ResultSet rs = buildResultSet(selector);
                while (rs.next())
                {
                        String temp = getValue(rs, selector);
                        String text = getText(rs, selector);
                        working.append("<option value=\"" + StringHelpers.escapeHTML(temp) + "\"");
                        for (int i = 0; i < values.length; i++)
                        {
                                if (temp.equalsIgnoreCase(values[i]))
                                {
                                        working.append(" selected=\"selected\" ");
                                        break;
                                }       
                        }
                        working.append(">");
                        if (text != null)
                        {
                                working.append(StringHelpers.escapeHTML(text));
                        }
                        
                        working.append("</option>");
                }
                working.append("</select>");
                return new String(working);
        }
        /**
         * Determine the value for option
         * @param rs Result set containing information for menu
         * @param selector Optional selector for controlling HTML generation
         * @return Text for value
         * @throws SQLException
         */
        protected String getValue(ResultSet rs, String selector) throws SQLException
        {
                String working = rs.getString("VALUE");
                if (rs.wasNull())
                {
                        return (String) null;
                }
                else
                {
                        return working;
                }
        }
        /**
         * Determine text value for the option
         * @param rs Result set containing information
         * @param selector Optional selector for controlling HTML generation
         * @return Text for caption
         * @throws SQLException
         */
        protected String getText(ResultSet rs, String selector) throws SQLException
        {
                String working = rs.getString("TEXT");
                if (rs.wasNull())
                {
                        return (String) null;
                }
                else
                {
                        return working;
                }
        }
        /**
         * Creates result set that is used to generate select tag.
         * @return Result set
         */
        protected ResultSet buildResultSet() throws SQLException
        {
                return buildResultSet((String) null);
        }
        /**
         * Generate the HTML code for a SELECT tag
         * that allows a single value to be selected.
         * 
         * @param name Name attribute for SELECT tag
         * @return HTML code
         */
        public String singleRequest(String name) throws SQLException
        {
                return singleRequest(name, (String) null, (String) null, (String) null);
        }
        /**
         * Generate the HTML code for a SELECT tag
         * that allows a single value to be selected.
         * 
         * @param name Name attribute for SELECT tag
         * @param value Existing value for selector
         * @return HTML code
         */
        public String singleRequest(String name, String value) throws SQLException
        {
                return singleRequest(name, value, (String) null, (String) null);
        }
        /**
         * Generate the HTML code for a SELECT tag that
         * allows multiple values to be selected.
         * 
         * @param name Name attribute for SELECT tag
         * @return HTML code
         */
        public String multipleRequest(String name) throws SQLException
        {
                return multipleRequest(name, (String[]) null, (String) null, (String) null);
        }
        /**
         * Generate the HTML code for a SELECT tag that
         * allows multiple values to be selected.
         * 
         * @param name Name attribute for SELECT tag
         * @param values Existing values for items in tag
         * @return HTML code
         */
        public String multipleRequest(String name, String[] values) throws SQLException
        {
                return multipleRequest(name, values, (String) null, (String) null);
        }
}