GridHandle.java

/*
** Module   : GridHandle.java
** Abstract : Grid handle.
**
** Copyright (c) 2017, Golden Code Development Corporation.
**
** -#- -I- --Date-- --------------------------------Description-----------------------------------
** 001 HC  20170612 Initial version.
*/
/*
** 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.
**
** 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 may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
**
**   0. Attribution Requirement.
**
**     You must preserve all legal notices or author attributions in the covered
**     work or Appropriate Legal Notices displayed by works containing the covered
**     work.  You may not remove from the covered work any author or developer
**     credit already included within the covered work.
**
**   1. No License To Use Trademarks.
**
**     This license does not grant any license or rights to use the trademarks
**     Golden Code, FWD, any Golden Code or FWD logo, or any other trademarks
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**     name Golden Code, FWD, or the names of any author or contributor, for
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*/
package com.goldencode.p2j.admin.client.widget;

import com.google.common.base.Predicate;
import com.google.common.collect.*;
import com.google.gwt.regexp.shared.*;
import com.google.gwt.user.cellview.client.*;
import com.google.gwt.view.client.*;

import java.util.*;

/**
 * A class providing convenience methods for working with instance of
 * {@link org.gwtbootstrap3.client.ui.gwt.DataGrid}.
 */
public class GridHandle<TRowObject>
{
   /** The wrapped grid */
   private DataGrid grid;

   /** Data provider */
   private ListDataProvider<TRowObject> dataProvider;

   /** Selection model reference */
   private SetSelectionModel<TRowObject> selectionModel;

   /** The selected records */
   private Set<TRowObject> selected;

   /**
    * Ctor.
    *
    * @param   grid
    *          The grid instance to wrap.
    * @param   dataProvider
    *          The data provider.
    * @param   selectionModel
    *          The selection model.
    */
   public GridHandle(DataGrid grid,
                     ListDataProvider<TRowObject> dataProvider,
                     SetSelectionModel<TRowObject> selectionModel)
   {
      this.grid = grid;
      this.dataProvider = dataProvider;
      this.selectionModel = selectionModel;
   }

   /**
    * Returns the wrapped grid.
    *
    * @return  see above
    */
   public DataGrid getGrid()
   {
      return grid;
   }

   /**
    * Returns the data provider.
    *
    * @return  see above
    */
   public ListDataProvider<TRowObject> getDataProvider()
   {
      return dataProvider;
   }

   /**
    * Returns the grid selection model.
    *
    * @return  see above
    */
   public SelectionModel<TRowObject> getSelectionModel()
   {
      return selectionModel;
   }

   /**
    * Unselects the currently selected rows.
    */
   public void clearSelection()
   {
      selected = null;
      selectionModel.clear();

      // this will make the (multi) selection model to apply any pending changes right away,
      // this is needed in case when a row is about change its key (see
      // AbstractSelectionModel.getKey())
      selectionModel.getSelectedSet();
   }

   /**
    * Returns the set of selected rows.
    *
    * @return  see above
    */
   public Set<TRowObject> getSelected()
   {
      return selectionModel.getSelectedSet();
   }

   /**
    * Return the single selected row. Note that this method can be used only when the
    * selection model is of type {@link SingleSelectionModel}.
    *
    * @return  see above
    */
   public TRowObject getSelectedSingle()
   {
      if (selectionModel instanceof SingleSelectionModel)
      {
         return ((SingleSelectionModel<TRowObject>) selectionModel).getSelectedObject();
      }
      else
      {
         throw new RuntimeException("Single selection model expected!");
      }
   }

   /**
    * Select the provided row. When the row is not present in the grid this method is a no-op.
    *
    * @param   row
    *          The row to select.
    */
   public void select(TRowObject row)
   {
      selected = null;
      selectionModel.setSelected(row, true);
   }

   /**
    * Clears the grid - removes all rows and clears the selection.
    */
   public void clearGrid()
   {
      clearGrid(true);
   }

   /**
    * Clears the grid - removes all rows and clears the selection.
    *
    * @param   keepSelection
    *          This flag allows to keep the current selection.
    */
   public void clearGrid(boolean keepSelection)
   {
      if (keepSelection)
      {
         storeSelected();
      }
      else
      {
         selected = null;
      }

      Set<TRowObject> rescue = selected;
      clearSelection();
      dataProvider.getList().clear();
      dataProvider.refresh();
      selected = rescue;
   }

   /**
    * Adds rows to the grid's data provider.
    *
    * @param   rows
    *          The rows to add.
    */
   public void addRows(List<TRowObject> rows)
   {
      dataProvider.getList().addAll(rows);
      restoreSelected();
   }

   /**
    * Adds rows to the grid's data provider.
    *
    * @param   rows
    *          The rows to add.
    */
   public void addRows(TRowObject[] rows)
   {
      dataProvider.getList().addAll(Arrays.asList(rows));
      ColumnSortEvent.fire(grid, grid.getColumnSortList());
      restoreSelected();
   }

   /**
    * Adds rows to the grid's data provider. Only those rows that satisfy the supplied
    * regular expression are added, all the row columns are tested against the expression.
    *
    * @param   rows
    *          The rows to add.
    * @param   filterExp
    *          Regular expression.
    */
   public void addRows(List<TRowObject> rows, RegExp filterExp)
   {
      Predicate<TRowObject> filterRecords = record ->
      {
         if (filterExp == null)
         {
            return true;
         }

         for (int i = 0; i < grid.getColumnCount(); i++)
         {
            Column<TRowObject, ?> column = grid.getColumn(i);
            if (filterExp.test(column.getValue(record).toString()))
            {
               return true;
            }
         }

         return false;
      };

      dataProvider.getList().addAll(Collections2.filter(rows, filterRecords));
      ColumnSortEvent.fire(grid, grid.getColumnSortList());
      restoreSelected();
   }

   /**
    * Adds rows to the grid's data provider. Only those rows that satisfy the supplied
    * regular expression are added, all the row columns are tested against the expression.
    *
    * @param   rows
    *          The rows to add.
    * @param   filterExp
    *          Regular expression.
    */
   public void addRows(TRowObject[] rows, RegExp filterExp)
   {
      addRows(Arrays.asList(rows), filterExp);
   }

   /**
    * Clears the grid and adds rows to the grid's data provider. This method keeps the current
    * grid selection.
    *
    * @param   rows
    *          The rows to set.
    */
   public void setRows(TRowObject[] rows)
   {
      clearGrid(true);
      addRows(rows);
      dataProvider.refresh();
   }

   /**
    * Clears the grid and adds rows to the grid's data provider. Only those rows that satisfy
    * the supplied regular expression are added, all the row columns are tested against
    * the expression.
    *
    * @param   rows
    *          The rows to set.
    * @param   filterExp
    *          Regular expression.
    */
   public void setRows(TRowObject[] rows, RegExp filterExp)
   {
      clearGrid(true);
      addRows(rows, filterExp);
      dataProvider.refresh();
      restoreSelected();
   }

   /**
    * Stores the currently selected rows.
    */
   private void storeSelected()
   {
      selected = new HashSet<>(selectionModel.getSelectedSet());
   }

   /**
    * Selects the rows stored by {@link #storeSelected()}.
    */
   private void restoreSelected()
   {
      if (selected != null)
      {
         List<TRowObject> list = dataProvider.getList();
         if (list != null)
         {
            for (TRowObject rec : selected)
            {
               selectionModel.setSelected(rec, false);

               int i = list.indexOf(rec);
               if (i >= 0)
               {
                  selectionModel.setSelected(list.get(i), true);
               }
            }
         }
      }
   }
}