content: /*
   * This library is part of OpenCms -
   * the Open Source Content Management System
   *
   * Copyright (c) Alkacon Software GmbH & Co. KG (https://www.alkacon.com)
   *
   * 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.
   *
   * For further information about Alkacon Software, please see the
   * company website: https://www.alkacon.com
   *
   * For further information about OpenCms, please see the
   * project website: https://www.opencms.org
   *
   * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  package org.opencms.widgets.dataview;
  
  import org.opencms.file.CmsObject;
  
  import java.util.List;
  import java.util.Locale;
  
  /**
   * Interface for a data source for use by CmsDataViewWidget.<p>
   *
   * This provides everything the widget needs to query an external data source, display the query
   * results (items) in tabular form, and provide the data to be stored when the user selects one or multiple items.
   */
  public interface I_CmsDataView {
  
      /**
       * Retrieves the list of columns to be displayed in the external data view widget.<p>
       *
       * This method should always return the same columns.
       *
       * @return a list of column definitions
       */
      List<CmsDataViewColumn> getColumns();
  
      /**
       * Gets the initial list of filters.<p>
       *
       * This is only used for the initial display of the data table; if the user changes the filters,
       * the method updateFilters() is called instead.
       *
       * @return the initial list of filters
       */
      List<CmsDataViewFilter> getFilters();
  
      /**
       * Retrieves the data item with the given id.<p>
       *
       * If no data item with that id exists, this method should return null.<p>
       *
       * @param id the id for which to retrieve the item
       *
       * @return the data item with the given the
       */
      I_CmsDataViewItem getItemById(String id);
  
      /**
       * Gets the page size, used for paging results.<p>
       *
       * @return the page size
       */
      int getPageSize();
  
      /**
       * Gets the result for the given query, with the given offset and limited to the given number of results.<p>
       *
       * The returned result includes a list of result items, and a total hit count for the given query (i.e. the number of results
       * that would be returned for offset 0 and unlimited result count). The hit count should be as accurate as possible.
       *
       * @param query the query
       * @param offset position of the first result to return (starts with 0)
       * @param count maximum number of results to return
       *
       * @return the result object
       */
      CmsDataViewResult getResults(CmsDataViewQuery query, int offset, int count);
  
      /**
       * Initializes this data view instance.<p>
       *
       * @param cms the CMS context to use for VFS operations
       * @param configData a string containing configuration data
       * @param locale the locale to use for the user interface
       */
      void initialize(CmsObject cms, String configData, Locale locale);
  
      /**
       * Returns an updated list of filters based on the current filters and their values.<p>
       *
       * This is called when the user changes any of the current filters in the data select widget.
       * The list passed as a parameter should not be modified, instead a new filter list should be returned.
       * If you do not need a dynamically changing set of filters, just return the argument 'prevFilters'
       * in your implementation.
       *
       * @param prevFilters the current set of filters
       * @return the new list of filters
       */
      List<CmsDataViewFilter> updateFilters(List<CmsDataViewFilter> prevFilters);
  
  }
  