Package org.springframework.jdbc.core

Class RowCountCallbackHandler

java.lang.Object
org.springframework.jdbc.core.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

  • Constructor Details

    • RowCountCallbackHandler

      public RowCountCallbackHandler()

  • Method Details

    • 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

      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