public class

RowCountCallbackHandler

extends Object
implements RowCallbackHandler
java.lang.Object
   ↳ org.springframework.jdbc.core.RowCountCallbackHandler

Class Overview

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();

Summary

Public Constructors
RowCountCallbackHandler()
Public Methods
final int getColumnCount()
Return the number of columns in this result set.
final String[] getColumnNames()
Return the names of the columns.
final int[] getColumnTypes()
Return the types of the columns as java.sql.Types constants Valid after processRow is invoked the first time.
final int getRowCount()
Return the row count of this ResultSet Only valid after processing is complete
final void processRow(ResultSet rs)
Implementation of ResultSetCallbackHandler.
Protected Methods
void processRow(ResultSet rs, int rowNum)
Subclasses may override this to perform custom extraction or processing.
[Expand]
Inherited Methods
From class java.lang.Object
From interface org.springframework.jdbc.core.RowCallbackHandler

Public Constructors

public RowCountCallbackHandler ()

Public Methods

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

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.

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.

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

public final void processRow (ResultSet rs)

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.

Parameters
rs the ResultSet to process (pre-initialized for the current row)
Throws
SQLException
See Also

Protected Methods

protected void processRow (ResultSet rs, int rowNum)

Subclasses may override this to perform custom extraction or processing. This class's implementation does nothing.

Parameters
rs ResultSet to extract data from. This method is invoked for each row
rowNum number of the current row (starting from 0)
Throws
SQLException