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

/*
 * JBoss, Home of Professional Open Source.
 * Copyright 2011, Red Hat, Inc., and individual contributors
 * as indicated by the @author tags. See the copyright.txt file in the
 * distribution for a full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jboss.as.cmp.jdbc;


/**
 * Generally, implementations of this interface map instances of one Java type
 * into instances of another Java type.
 * Mappers are used in cases when instances of "enum" types are used as CMP
 * field values. In this case, a mapper represents a mediator and translates
 * instances of "enum" to some id when that can be stored in a column when storing
 * data and back from id to "enum" instance when data is loaded.
 *
 * @author <a href="mailto:alex@jboss.org">Alex Loubyansky</a>
 */
public interface Mapper {
    /**
     * This method is called when CMP field is stored.
     *
     * @param fieldValue - CMP field value
     * @return column value.
     */
    Object toColumnValue(Object fieldValue);

    /**
     * This method is called when CMP field is loaded.
     *
     * @param columnValue - loaded column value.
     * @return CMP field value.
     */
    Object toFieldValue(Object columnValue);
}