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Java > Open Source Codes > org > jboss > ejb > plugins > cmp > jdbc > Mapper


1 /*
2 * JBoss, Home of Professional Open Source
3 * Copyright 2005, JBoss Inc., and individual contributors as indicated
4 * by the @authors tag. See the copyright.txt in the distribution for a
5 * full listing of individual contributors.
6 *
7 * This is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU Lesser General Public License as
9 * published by the Free Software Foundation; either version 2.1 of
10 * the License, or (at your option) any later version.
11 *
12 * This software is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with this software; if not, write to the Free
19 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
20 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
21 */

22 package org.jboss.ejb.plugins.cmp.jdbc;
23
24
25 /**
26  * Generally, implementations of this interface map instances of one Java type
27  * into instances of another Java type.
28  * Mappers are used in cases when instances of "enum" types are used as CMP
29  * field values. In this case, a mapper represents a mediator and translates
30  * instances of "enum" to some id when that can be stored in a column when storing
31  * data and back from id to "enum" instance when data is loaded.
32  *
33  * @author <a HREF="mailto:alex@jboss.org">Alex Loubyansky</a>
34  */

35 public interface Mapper
36 {
37    /**
38     * This method is called when CMP field is stored.
39     * @param fieldValue - CMP field value
40     * @return column value.
41     */

42    Object JavaDoc toColumnValue(Object JavaDoc fieldValue);
43
44    /**
45     * This method is called when CMP field is loaded.
46     * @param columnValue - loaded column value.
47     * @return CMP field value.
48     */

49    Object JavaDoc toFieldValue(Object JavaDoc columnValue);
50 }
51
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