[DBUTILS-6] [dbutils] Create handler to return a Map of Maps

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Duplicate

Environment

Operating System: All
Platform: All

• Bugzilla Id: 32449
• Assignee: Unassigned
• Reporter: Norris Shelton
• Created: 01/Dec/04 00:55
• Updated: 02/Jan/08 07:29
• Resolved: 02/Jan/08 07:29

Description

Turns a result set into a map of maps. I needed it to turn a
result set into a map of state abbreviations keys with state
information maps as values.

It has 2 constructors. The empty constructor assumes that there
is going to be a column named "key" that will serve as the map
key. There is another constructor that takes a String that is
used to identify the key column.

Here is the code:
package com.appriss.justicexchange.util.dbutils;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.*;

import org.apache.commons.dbutils.BasicRowProcessor;
import org.apache.commons.dbutils.ResultSetHandler;
import org.apache.commons.dbutils.RowProcessor;
import org.apache.commons.dbutils.handlers.MapListHandler;

/**

• <code>ResultSetHandler</code> implementation that converts a
• <code>ResultSet</code> into a <code>Map</code> of <code>Map</code>s.
• This class is thread safe.
  *
• @see org.apache.commons.dbutils.ResultSetHandler
  *
• @author David Graham
• @author Norris Shelton
  */
  public class MapMapHandler extends MapListHandler implements ResultSetHandler {

private String key = "key";

/**

• The RowProcessor implementation to use when converting rows
• into Maps.
  */
  private RowProcessor convert = BasicRowProcessor.instance();

/**

• Creates a new instance of MapMapHandler using a
• <code>BasicRowProcessor</code> for conversion. Assumes that the key for
• the map will be "key".
  */
  public MapMapHandler() { super(); }

/**

• Creates a new instance of MapMapHandler using a
• <code>BasicRowProcessor</code> for conversion. The provided key String
• will be the key for each map.
  */
  public MapMapHandler(String key) { super(); this.key = key; }

/**

• Creates a new instance of MapMapHandler.
  *
• @param convert The <code>RowProcessor</code> implementation
• to use when converting rows into Maps. Assumes that the key for
• the map will be "key".
  */
  public MapMapHandler(RowProcessor convert) { super(); this.convert = convert; }

/**

• Converts the <code>ResultSet</code> rows into a <code>Map</code> of
• <code>Map</code> objects.
  *
• @return A <code>Map</code> of <code>Map</code>s, never null.
  *
• @throws java.sql.SQLException
  *
• @see org.apache.commons.dbutils.ResultSetHandler#handle(java.sql.ResultSet)
  */
  public Object handle(ResultSet rs) throws SQLException {

Map results = new HashMap();

Map temp = null;
while (rs.next())

{ temp = convert.toMap(rs); results.put(temp.get(key), temp); }

return results;
}
}