com.perdues.db
Interface DBTypeHandler

All Known Implementing Classes:

SSNTypeHandler, DateTypeHandler, StringTypeHandler, NumericTypeHandler, EmailTypeHandler, BaseTypeHandler, IDTypeHandler

public interface DBTypeHandler

Each Schema object has an associated set of classes that perform various type-specific actions based on the extended types specified in the Schema. These database type handler classes must implement the DBTypeHandler interface.

Method Summary

java.lang.String	renderForSQL(ColumnInfo col, Form form, java.lang.String field) Renders a form field given by name into an SQL literal, based on the extended type given by the ColumnInfo.
void	storeToForm(ColumnInfo col, java.sql.ResultSet rs, int rsField, Form form, java.lang.String field) Stores the value of the numbered field of the ResultSet into the given field of the form.
void	storeToForm(ColumnInfo col, java.sql.ResultSet rs, java.lang.String rsField, Form form, java.lang.String field) Stores the value of the named field of the ResultSet into the given field of the form.
void	validate(ColumnInfo col, Form form, java.util.Hashtable errors) Validates a Form field based on type information from the extended database schema.

Method Detail

renderForSQL

public java.lang.String renderForSQL(ColumnInfo col,
                                     Form form,
                                     java.lang.String field)

Renders a form field given by name into an SQL literal, based on the extended type given by the ColumnInfo. The type handler may also normalize the value that is actually in the form, for example stripping leading or trailing whitespace. Returns the literal in a String.

This method takes a field name as well as a ColumnInfo so code that calls this can try different variations on the field name to allow the field name to encode the table name as well as the column name. Must return null if the logical field is not present in the form.

storeToForm

public void storeToForm(ColumnInfo col,
                        java.sql.ResultSet rs,
                        java.lang.String rsField,
                        Form form,
                        java.lang.String field)
                 throws java.sql.SQLException

Stores the value of the named field of the ResultSet into the given field of the form.

storeToForm

public void storeToForm(ColumnInfo col,
                        java.sql.ResultSet rs,
                        int rsField,
                        Form form,
                        java.lang.String field)
                 throws java.sql.SQLException

Stores the value of the numbered field of the ResultSet into the given field of the form.

validate

public void validate(ColumnInfo col,
                     Form form,
                     java.util.Hashtable errors)

Validates a Form field based on type information from the extended database schema. For any validation problems, the method should add entries to errors, a Hashtable with String keys that are fully-qualified database field names and values that are String messages describing what is required for the form field. A validator is required to check validity as fully as practical. This validation is intended for data entry, to check as far as possible that each data item can be properly stored into the database.

TableInfo.validateRecord calls this for every column of the table so it can accommodate "virtual" form fields that don't map 1-to-1 onto columns.