01: /*
02: * JBoss, Home of Professional Open Source.
03: * Copyright 2006, Red Hat Middleware LLC, and individual contributors
04: * as indicated by the @author tags. See the copyright.txt file in the
05: * distribution for a full listing of individual contributors.
06: *
07: * This is free software; you can redistribute it and/or modify it
08: * under the terms of the GNU Lesser General Public License as
09: * 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: * Generally, implementations of this interface map instances of one Java type
26: * into instances of another Java type.
27: * Mappers are used in cases when instances of "enum" types are used as CMP
28: * field values. In this case, a mapper represents a mediator and translates
29: * instances of "enum" to some id when that can be stored in a column when storing
30: * data and back from id to "enum" instance when data is loaded.
31: *
32: * @author <a href="mailto:alex@jboss.org">Alex Loubyansky</a>
33: */
34: public interface Mapper {
35: /**
36: * This method is called when CMP field is stored.
37: * @param fieldValue - CMP field value
38: * @return column value.
39: */
40: Object toColumnValue(Object fieldValue);
41:
42: /**
43: * This method is called when CMP field is loaded.
44: * @param columnValue - loaded column value.
45: * @return CMP field value.
46: */
47: Object toFieldValue(Object columnValue);
48: }
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