Package com.im.commons.db.columnhandling

Interface DBValueHandler<T>

  • Type Parameters:
    T - type of handled value
    public interface DBValueHandler<T>
    Interface that handles reading/writing values from/to a database. Values are potentially complex objects whose values are persisted in multiple database columns of different types.
    Author:
    Tim Dudgeon

    • Method Detail

      • getColumnNames

        java.lang.String[] getColumnNames()
        The names of the column(s) used to store these values. Note that the array can be empty.
        Returns:
        The column names

      • getColumnJdbcTypes

        int[] getColumnJdbcTypes()
        The JDBC type(s) as defined in Types. Note that the array can be empty.
        Returns:
        the column types

      • getColumnTypes

        DBDatabaseInfo.ColumnSQLType[] getColumnTypes()
        The SQL type of the column(s). Note that the array can be empty.
        Returns:
        The SQL type of the column(s)

      • createRowMapper

        org.springframework.jdbc.core.RowMapper<T> createRowMapper()
        Creates a RowMapper instance capable of reading and assembling the value from a ResultSet. The RowMapper will use ColumnHandler for each of the columns grouped under this handler to read this column's value. It will then call assembleValue(Object[]) to combine those column values into the final result.
        Returns:
        A row mapper for reading the assembled value from a ResultSet.

      • bindVariable

        void bindVariable​(java.sql.PreparedStatement stmt,
                  T value,
                  int[] indexes)
           throws java.sql.SQLException
        Bind the variable to the PreparedStatement. Only for simple column types that do not need special treatment, such as LobHandler TODO - this method may be replaced with something more generic in the future
        Parameters:
        stmt - The PreparedStatement
        value - The value to bind. Will be disassembled into the corresponding values for each column.
        indexes - The positional indexes of parameter holders for each column, starting from 1
        Throws:
        java.sql.SQLException - If the operation fails.

      • assembleValue

        T assembleValue​(java.lang.Object[] v)
        Assemble the value from the values stored in the DB columns. For single column values this will be the value itself, but for multi-column values the value for each column must be assembled into the appropriate object.
        Parameters:
        v - The column values to assemble
        Returns:
        The assembled values

      • dissasembleValue

        java.lang.Object[] dissasembleValue​(T v)
        Split the value up into its components suitable for storing in each column. For single column values this will be the value itself, but for multi-column values the value must be split up into its composite parts for each column.
        Parameters:
        v - The value to disassemble
        Returns:
        The disassembled parts

      • getAssembledValueClass

        java.lang.Class<T> getAssembledValueClass()
        Returns:
        The class of the assembled values

      • getDisassembledValuesClasses

        java.lang.Class[] getDisassembledValuesClasses()
        Returns:
        The classes of the disassembled values suitable for storing in each column