/*
    * Copyright 2003 - 2013 The eFaps Team
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *     http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *
   * Revision:        $Rev$
   * Last Changed:    $Date$
   * Last Changed By: $Author$
   */
  
  package org.efaps.db.wrapper;
  
  import java.sql.Connection;
  import java.sql.PreparedStatement;
  import java.sql.SQLException;
  
  import org.efaps.db.Context;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  
  /**
   * <p>An easy wrapper for a SQL update statement. To initialize this class use
   * {@link org.efaps.db.databases.AbstractDatabase#newUpdate(String, String, long)}
   * to get a database specific update.</p>
   *
   * <p><b>Example:</b><br/>
   * <pre>
   * SQLUpdate insert = Context.getDbType().newUpdate("MYTABLE", "ID", 12);
   * </pre></p>
   *
   * @author The eFaps Team
   * @version $Id$
   */
  public class SQLUpdate
      extends AbstractSQLInsertUpdate<SQLUpdate>
  {
      /**
       * Logging instance used in this class.
       */
      private static final Logger LOG = LoggerFactory.getLogger(SQLUpdate.class);
  
      /**
       * Id of the row which is updated.
       */
      private final long id;
  
  
      /**
       * Initializes this update. Do not call the constructor directly, instead
       * use
       * {@link org.efaps.db.databases.AbstractDatabase#newUpdate(String, String, long)}
       * to get the database specific implementation.
       *
       * @param _tableName    name of the table to update
       * @param _idCol        name of the column with the id
       * @param _id           id to update
       */
      public SQLUpdate(final String _tableName,
                       final String _idCol,
                       final long _id)
      {
          super(_tableName, _idCol);
          this.id = _id;
      }
  
      /**
       * Executes the SQL update.
       *
       * @param _con      SQL connection
       * @throws SQLException if update failed or the row for given {@link #id}
       *                      does not exists
       */
      public void execute(final Connection _con)
          throws SQLException
      {
          final StringBuilder cmd = new StringBuilder()
              .append(Context.getDbType().getSQLPart(SQLPart.UPDATE)).append(" ")
              .append(Context.getDbType().getTableQuote())
              .append(getTableName())
              .append(Context.getDbType().getTableQuote()).append(" ")
              .append(Context.getDbType().getSQLPart(SQLPart.SET)).append(" ");
  
          // append SQL values
          boolean first = true;
          for (final ColumnWithSQLValue col : getColumnWithSQLValues())  {
              if (first)  {
                  first = false;
              } else  {
                 cmd.append(Context.getDbType().getSQLPart(SQLPart.COMMA));
             }
             cmd.append(Context.getDbType().getColumnQuote())
                 .append(col.getColumnName())
                 .append(Context.getDbType().getColumnQuote())
                 .append(Context.getDbType().getSQLPart(SQLPart.EQUAL))
                 .append(col.getSqlValue());
         }
 
         // append values
         for (final AbstractColumnWithValue<?> col : getColumnWithValues())  {
             if (first)  {
                 first = false;
             } else  {
                 cmd.append(Context.getDbType().getSQLPart(SQLPart.COMMA));
             }
             cmd.append(Context.getDbType().getColumnQuote())
                 .append(col.getColumnName())
                 .append(Context.getDbType().getColumnQuote())
                 .append(Context.getDbType().getSQLPart(SQLPart.EQUAL))
                 .append("?");
         }
 
         // append where clause
         cmd.append(" ").append(Context.getDbType().getSQLPart(SQLPart.WHERE)).append(" ")
             .append(Context.getDbType().getColumnQuote())
             .append(getIdColumn())
             .append(Context.getDbType().getColumnQuote())
             .append(Context.getDbType().getSQLPart(SQLPart.EQUAL))
             .append("?");
 
         if (SQLUpdate.LOG.isDebugEnabled()) {
             SQLUpdate.LOG.debug(cmd.toString());
         }
 
         final PreparedStatement stmt = _con.prepareStatement(cmd.toString());
         int index = 1;
         for (final AbstractColumnWithValue<?> col : getColumnWithValues())  {
             if (SQLUpdate.LOG.isDebugEnabled()) {
                 SQLUpdate.LOG.debug("    " + index + " = " + col.getValue());
             }
             col.set(index++, stmt);
         }
 
         if (SQLUpdate.LOG.isDebugEnabled()) {
             SQLUpdate.LOG.debug("    " + index + " = " + this.id);
         }
         stmt.setLong(index, this.id);
 
         try  {
             final int rows = stmt.executeUpdate();
             if (rows == 0) {
                 throw new SQLException("Object for SQL table '" + getTableName()
                         + "' with id '" + this.id + "' does not exists and was not updated.");
             }
         } finally  {
             stmt.close();
         }
     }
 
     /**
      * Getter method for the instance variable {@link #id}.
      *
      * @return value of instance variable {@link #id}
      */
     public long getId()
     {
         return this.id;
     }
 }