/jboss-as-7.1.1.Final/cmp/src/main/java/org/jboss/as/cmp/jdbc/Mapper.java

 1/*
 2 * JBoss, Home of Professional Open Source.
 3 * Copyright 2011, Red Hat, Inc., and individual contributors
 4 * as indicated by the @author tags. See the copyright.txt file in the
 5 * distribution for a 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 */
22package org.jboss.as.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 */
35public interface Mapper {
36    /**
37     * This method is called when CMP field is stored.
38     *
39     * @param fieldValue - CMP field value
40     * @return column value.
41     */
42    Object toColumnValue(Object fieldValue);
43
44    /**
45     * This method is called when CMP field is loaded.
46     *
47     * @param columnValue - loaded column value.
48     * @return CMP field value.
49     */
50    Object toFieldValue(Object columnValue);
51}