Mapper.java :  » Database-ORM » ODAL » com » completex » objective » components » persistency » mapper » Java Open Source

package com.completex.objective.components.persistency.mapper;

/**
 * Establishes map between Persistent Objects and Domain Objects that can be POJOs.
 * Inability to map the value should normally be tolerated. 
 * 
 * @author Gennady Krizhevsky
 */
public interface Mapper {
    
    public static final NullMapper NULL_MAPPER = new NullMapper();

    /**
     * Converts Persistent Object to POJO bean. If the mapping not found it should normally return
     * unconverted Persistent Object.
     * 
     * @param po Persistent Object
     * @param forModification if true, indicates to cache Persistent Object in Thread Session 
     * @return POJO bean
     */
    Object convertPoToBean(Object po, boolean forModification);

    /**
     * Converts POJO bean to Persistent Object. 
     * 
     * @param bean POJO bean
     * @param forModification if true, indicates to cache Persistent Object in Thread Session
     * @return Persistent Object
     * @throws OdalMappingRuntimeException if the mapping is not found
     */
    Object convertBeanToPo(Object bean, boolean forModification);

    /**
     * Returns true is the mapping found. At least one of the arguments should not be null.
     * 
     * @param beanClass bean class
     * @param poClass  persistent object class
     * @return true is the mapping found
     */
    boolean mappingExists(Class beanClass, Class poClass);


    /**
     * Null implementation of Mapper
     */
    static class NullMapper implements Mapper {

        protected NullMapper() {
        }

        public Object convertPoToBean(Object po, boolean forModification) {
            return po;
        }

        public Object convertBeanToPo(Object bean, boolean forModification) {
            return bean;
        }

        public boolean mappingExists(Class beanClass, Class poClass) {
            return false;
        }
    }
}