Class BeanMapHandler<K,​V>

  • Type Parameters:
    K - the type of keys maintained by the returned map
    V - the type of the bean
    All Implemented Interfaces:
    ResultSetHandler<java.util.Map<K,​V>>

    public class BeanMapHandler<K,​V>
    extends AbstractKeyedHandler<K,​V>

    ResultSetHandler implementation that returns a Map of Beans. ResultSet rows are converted into Beans which are then stored in a Map under the given key.

    If you had a Person table with a primary key column called ID, you could retrieve rows from the table like this:

     ResultSetHandler<Map<Long, Person>> h = new BeanMapHandler<Long, Person>(Person.class, "id");
     Map<Long, Person> found = queryRunner.query("select id, name, age from person", h);
     Person jane = found.get(1L); // jane's id is 1
     String janesName = jane.getName();
     Integer janesAge = jane.getAge();
     
    Note that the "id" passed to BeanMapHandler can be in any case. The data type returned for id is dependent upon how your JDBC driver converts SQL column types from the Person table into Java types. The "name" and "age" columns are converted according to their property descriptors by DbUtils. </p>

    This class is thread safe. </p>

    Since:
    DbUtils 1.5
    See Also:
    ResultSetHandler
    • Field Summary

      Fields 
      Modifier and Type Field Description
      private int columnIndex
      The column index to retrieve key values from.
      private java.lang.String columnName
      The column name to retrieve key values from.
      private RowProcessor convert
      The RowProcessor implementation to use when converting rows into Objects.
      private java.lang.Class<V> type
      The Class of beans produced by this handler.
    • Constructor Summary

      Constructors 
      Modifier Constructor Description
        BeanMapHandler​(java.lang.Class<V> type)
      Creates a new instance of BeanMapHandler.
        BeanMapHandler​(java.lang.Class<V> type, int columnIndex)
      Creates a new instance of BeanMapHandler.
        BeanMapHandler​(java.lang.Class<V> type, java.lang.String columnName)
      Creates a new instance of BeanMapHandler.
        BeanMapHandler​(java.lang.Class<V> type, RowProcessor convert)
      Creates a new instance of BeanMapHandler.
      private BeanMapHandler​(java.lang.Class<V> type, RowProcessor convert, int columnIndex, java.lang.String columnName)
      Private Helper
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected K createKey​(java.sql.ResultSet rs)
      This factory method is called by handle() to retrieve the key value from the current ResultSet row.
      protected V createRow​(java.sql.ResultSet rs)
      This factory method is called by handle() to store the current ResultSet row in some object.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Field Detail

      • type

        private final java.lang.Class<V> type
        The Class of beans produced by this handler.
      • convert

        private final RowProcessor convert
        The RowProcessor implementation to use when converting rows into Objects.
      • columnIndex

        private final int columnIndex
        The column index to retrieve key values from. Defaults to 1.
      • columnName

        private final java.lang.String columnName
        The column name to retrieve key values from. Either columnName or columnIndex will be used but never both.
    • Constructor Detail

      • BeanMapHandler

        public BeanMapHandler​(java.lang.Class<V> type)
        Creates a new instance of BeanMapHandler. The value of the first column of each row will be a key in the Map.
        Parameters:
        type - The Class that objects returned from createRow() are created from.
      • BeanMapHandler

        public BeanMapHandler​(java.lang.Class<V> type,
                              RowProcessor convert)
        Creates a new instance of BeanMapHandler. The value of the first column of each row will be a key in the Map.
        Parameters:
        type - The Class that objects returned from createRow() are created from.
        convert - The RowProcessor implementation to use when converting rows into Beans
      • BeanMapHandler

        public BeanMapHandler​(java.lang.Class<V> type,
                              int columnIndex)
        Creates a new instance of BeanMapHandler.
        Parameters:
        type - The Class that objects returned from createRow() are created from.
        columnIndex - The values to use as keys in the Map are retrieved from the column at this index.
      • BeanMapHandler

        public BeanMapHandler​(java.lang.Class<V> type,
                              java.lang.String columnName)
        Creates a new instance of BeanMapHandler.
        Parameters:
        type - The Class that objects returned from createRow() are created from.
        columnName - The values to use as keys in the Map are retrieved from the column with this name.
      • BeanMapHandler

        private BeanMapHandler​(java.lang.Class<V> type,
                               RowProcessor convert,
                               int columnIndex,
                               java.lang.String columnName)
        Private Helper
        Parameters:
        convert - The RowProcessor implementation to use when converting rows into Beans
        columnIndex - The values to use as keys in the Map are retrieved from the column at this index.
        columnName - The values to use as keys in the Map are retrieved from the column with this name.
    • Method Detail

      • createKey

        protected K createKey​(java.sql.ResultSet rs)
                       throws java.sql.SQLException
        This factory method is called by handle() to retrieve the key value from the current ResultSet row.
        Specified by:
        createKey in class AbstractKeyedHandler<K,​V>
        Parameters:
        rs - ResultSet to create a key from
        Returns:
        K from the configured key column name/index
        Throws:
        java.sql.SQLException - if a database access error occurs
        java.lang.ClassCastException - if the class datatype does not match the column type
        See Also:
        AbstractKeyedHandler.createKey(ResultSet)
      • createRow

        protected V createRow​(java.sql.ResultSet rs)
                       throws java.sql.SQLException
        Description copied from class: AbstractKeyedHandler
        This factory method is called by handle() to store the current ResultSet row in some object.
        Specified by:
        createRow in class AbstractKeyedHandler<K,​V>
        Parameters:
        rs - ResultSet to create a row from
        Returns:
        V object created from the current row
        Throws:
        java.sql.SQLException - if a database access error occurs