# AbstractColumnValuePredicate.java

    /*
     * Copyright (C) 2000 - 2024 Silverpeas
     *
     * This program is free software: you can redistribute it and/or modify
     * it under the terms of the GNU Affero General Public License as
     * published by the Free Software Foundation, either version 3 of the
     * License, or (at your option) any later version.
     *
     * As a special exception to the terms and conditions of version 3.0 of
     * the GPL, you may redistribute this Program in connection with Free/Libre
     * Open Source Software ("FLOSS") applications as described in Silverpeas's
     * FLOSS exception.  You should have received a copy of the text describing
     * the FLOSS exception, and it is also available here:
     * "https://www.silverpeas.org/legal/floss_exception.html"
     *
     * This program 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 Affero General Public License for more details.
     *
     * You should have received a copy of the GNU Affero General Public License
     * along with this program.  If not, see <https://www.gnu.org/licenses/>.
     */

    package org.silverpeas.components.mydb.model.predicates;

    import org.silverpeas.components.mydb.model.DbColumn;
    import org.silverpeas.core.persistence.jdbc.sql.JdbcSqlQuery;

    /**
     * Abstract implementation of the {@link ColumnValuePredicate} interface.
     * @author mmoquillon
     */
    public abstract class AbstractColumnValuePredicate implements ColumnValuePredicate {

      public static final String NULL_VALUE = "null";
      public static final String EMPTY_VALUE = "@empty@";
      private DbColumn column;
      private String value;
      private Object normalizedValue;

      /**
       * Constructs a new predicate on the specified database table's column and with the given
       * reference value.
       * @param column the column.
       * @param refValue a reference value.
       */
      public AbstractColumnValuePredicate(final DbColumn column, final String refValue) {
        this.column = column;
        this.value = refValue;
        this.normalizedValue = normalizeValue(column, refValue);
      }

      /**
       * Constructs an empty predicate. Dedicated to the concrete implementation of a predicate only
       * if they have to perform some specified tasks at initialization time.
       */
      AbstractColumnValuePredicate() {
        // dedicated to the implementors
      }

      private static Object normalizeValue(final DbColumn column, final String value) {
        final Object normalizedValue;
        if (NULL_VALUE.equals(value)) {
          normalizedValue = null;
        } else if (EMPTY_VALUE.equals(value)) {
          normalizedValue = "";
        } else {
          normalizedValue = column.getJdbcValueOf(value);
        }
        return normalizedValue;
      }

      Object getNormalizedValue() {
        return this.normalizedValue;
      }

      @Override
      public DbColumn getColumn() {
        return this.column;
      }

      @Override
      public Comparable getReferenceValue() {
        return this.value;
      }

      public abstract JdbcSqlQuery apply(final JdbcSqlQuery query);
    }