Package org.springframework.jdbc.core

Class RowCountCallbackHandler

  • All Implemented Interfaces:
    RowCallbackHandler
    public class RowCountCallbackHandler
extends Object
implements RowCallbackHandler
    Implementation of RowCallbackHandler. Convenient superclass for callback handlers. An instance can only be used once.

    We can either use this on its own (for example, in a test case, to ensure that our result sets have valid dimensions), or use it as a superclass for callback handlers that actually do something, and will benefit from the dimension information it provides.

    A usage example with JdbcTemplate: 

    JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);  // reusable object

 RowCountCallbackHandler countCallback = new RowCountCallbackHandler();  // not reusable
 jdbcTemplate.query("select * from user", countCallback);
 int rowCount = countCallback.getRowCount();
    Since:
    May 3, 2001
    Author:
    Rod Johnson

    • Method Detail

      • processRow

        public final void processRow​(ResultSet rs)
                      throws SQLException
        Implementation of ResultSetCallbackHandler. Work out column size if this is the first row, otherwise just count rows.

        Subclasses can perform custom extraction or processing by overriding the processRow(ResultSet, int) method.

        Specified by:
        processRow in interface RowCallbackHandler
        Parameters:
        rs - the ResultSet to process (pre-initialized for the current row)
        Throws:
        SQLException - if an SQLException is encountered getting column values (that is, there's no need to catch SQLException)
        See Also:
        processRow(java.sql.ResultSet, int)

      • processRow

        protected void processRow​(ResultSet rs,
                          int rowNum)
                   throws SQLException
        Subclasses may override this to perform custom extraction or processing. This class's implementation does nothing.
        Parameters:
        rs - the ResultSet to extract data from. This method is invoked for each row
        rowNum - number of the current row (starting from 0)
        Throws:
        SQLException

      • getColumnTypes

        @Nullable
public final int[] getColumnTypes()
        Return the types of the columns as java.sql.Types constants Valid after processRow is invoked the first time.
        Returns:
        the types of the columns as java.sql.Types constants. Indexed from 0 to n-1.

      • getColumnNames

        @Nullable
public final String[] getColumnNames()
        Return the names of the columns. Valid after processRow is invoked the first time.
        Returns:
        the names of the columns. Indexed from 0 to n-1.

      • getRowCount

        public final int getRowCount()
        Return the row count of this ResultSet. Only valid after processing is complete
        Returns:
        the number of rows in this ResultSet

      • getColumnCount

        public final int getColumnCount()
        Return the number of columns in this result set. Valid once we've seen the first row, so subclasses can use it during processing
        Returns:
        the number of columns in this result set