py.una.pol.karaku.util.UniqueHelper.java Source code

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Here is the source code for py.una.pol.karaku.util.UniqueHelper.java

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/*-
 * Copyright (c)
 *
 *       2012-2014, Facultad Politcnica, Universidad Nacional de Asuncin.
 *       2012-2014, Facultad de Ciencias Mdicas, Universidad Nacional de Asuncin.
 *       2012-2013, Centro Nacional de Computacin, Universidad Nacional de Asuncin.
 *
 * This library 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 library 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */
package py.una.pol.karaku.util;

import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.hibernate.exception.ConstraintViolationException;
import org.springframework.stereotype.Component;
import py.una.pol.karaku.exception.UniqueConstraintException;
import py.una.pol.karaku.model.Unique;

/**
 * Componente que se utiliza para convertir Excepciones a excepciones del tipo
 * {@link UniqueConstraintException}, para poder obtener una referencia a los
 * atributos que fallaron cuando el SQL fracaso.
 * 
 * @author Arturo Volpe Torres
 * @since 1.0
 * @version 1.0 Feb 19, 2013
 * 
 */
@Component
public class UniqueHelper {

    /**
     * Si es una exception {@link ConstraintViolationException} que viene de la
     * base de datos, entonces recupera informacin valiosa y genera una
     * Excepcin {@link UniqueConstraintException}.
     * 
     * @param exception
     *            Excepcion genrica
     * @param clazz
     *            Clase de la entidad duea de los atributos
     * @return {@link UniqueConstraintException} si es el caso, o la misma
     *         Excepcin que se recibe
     */
    public Exception createUniqueException(final Exception exception, final Class<?> clazz) {

        if (exception instanceof ConstraintViolationException) {
            ConstraintViolationException cve = (ConstraintViolationException) exception;
            String constraint = cve.getConstraintName();
            Map<String, UniqueRestrintion> constrainsName = getConstrains(clazz);
            if (constrainsName.get(constraint) != null) {
                UniqueRestrintion ur = constrainsName.get(constraint);
                return new UniqueConstraintException(ur);
            }
        }
        return exception;
    }

    private Map<String, UniqueRestrintion> getConstrains(final Class<?> clazz) {

        // TODO esto se crea cada vez que surge una excepcin, considerar la
        // posibilidad de guardarlo y utilizarlo mas tarde.
        Map<String, UniqueRestrintion> restrintions = new HashMap<String, UniqueRestrintion>();
        for (Field f : clazz.getDeclaredFields()) {
            Unique uniqueName = f.getAnnotation(Unique.class);
            if (uniqueName != null) {
                for (String fieldConstraint : uniqueName.value()) {
                    UniqueRestrintion restrintion = restrintions.get(fieldConstraint);
                    if (restrintion == null) {
                        restrintion = new UniqueRestrintion(fieldConstraint);
                        restrintions.put(fieldConstraint, restrintion);
                    }
                    restrintion.addField(f.getName());
                }
            }
        }

        return restrintions;
    }

    /**
     * Clase auxiliar que se utiliza para agrupar logicamente un constraint de
     * base de datos con su atributo en una entidad.
     * 
     * @author Arturo Volpe Torres
     * @since 1.0
     * @version 1.0 Feb 19, 2013
     * 
     */
    public static class UniqueRestrintion {

        private String uniqueConstraintName;
        private List<String> fields;

        protected UniqueRestrintion(final String uniqueConstraintName) {

            this.uniqueConstraintName = uniqueConstraintName;
        }

        /**
         * Agrega un nuevo field a la lista de fields manejados por esta clase
         * 
         * @param field
         */
        public void addField(final String field) {

            if (fields == null) {
                fields = new ArrayList<String>(2);
            }
            fields.add(field);
        }

        /**
         * Retorna la lista de elementos manejados por esta clase
         * 
         * @return lista de fields
         */
        public List<String> getFields() {

            return fields;
        }

        /**
         * Retorna el nombre del constraint
         * 
         * @return nombre de constraint de base de datos
         */
        public String getUniqueConstraintName() {

            return uniqueConstraintName;
        }
    }
}