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   1 /*
   2  * Copyright 2000-2021 Vaadin Ltd.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
   5  * use this file except in compliance with the License. You may obtain a copy of
   6  * the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  12  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
  13  * License for the specific language governing permissions and limitations under
  14  * the License.
  15  */
  16 package com.vaadin.v7.client.widget.grid.selection;
  17
  18 import java.util.Collection;
  19 import java.util.Collections;
  20
  21 import com.vaadin.client.data.DataSource.RowHandle;
  22 import com.vaadin.v7.client.renderers.Renderer;
  23 import com.vaadin.v7.client.widgets.Grid;
  24
  25 /**
  26  * Single-row selection model.
  27  *
  28  * @author Vaadin Ltd
  29  * @since 7.4
  30  */
  31 public class SelectionModelSingle<T> extends AbstractRowHandleSelectionModel<T>
  32         implements SelectionModel.Single<T>, HasUserSelectionAllowed<T> {
  33
  34     private Grid<T> grid;
  35     private RowHandle<T> selectedRow;
  36
  37     /** Event handling for selection with space key */
  38     private SpaceSelectHandler<T> spaceSelectHandler;
  39
  40     /** Event handling for selection by clicking cells */
  41     private ClickSelectHandler<T> clickSelectHandler;
  42
  43     private boolean deselectAllowed = true;
  44     private boolean userSelectionAllowed = true;
  45
  46     @Override
  47     public boolean isSelected(T row) {
  48         return selectedRow != null
  49                 && selectedRow.equals(grid.getDataSource().getHandle(row));
  50     }
  51
  52     @Override
  53     public Renderer<Boolean> getSelectionColumnRenderer() {
  54         // No Selection column renderer for single selection
  55         return null;
  56     }
  57
  58     @Override
  59     public void setGrid(Grid<T> grid) {
  60         if (this.grid != null && grid != null) {
  61             // Trying to replace grid
  62             throw new IllegalStateException(
  63                     "Selection model is already attached to a grid. "
  64                             + "Remove the selection model first from "
  65                             + "the grid and then add it.");
  66         }
  67
  68         this.grid = grid;
  69         if (this.grid != null) {
  70             spaceSelectHandler = new SpaceSelectHandler<T>(grid);
  71             clickSelectHandler = new ClickSelectHandler<T>(grid);
  72             updateHandlerDeselectAllowed();
  73         } else {
  74             spaceSelectHandler.removeHandler();
  75             clickSelectHandler.removeHandler();
  76             spaceSelectHandler = null;
  77             clickSelectHandler = null;
  78         }
  79     }
  80
  81     @Override
  82     public boolean select(T row) {
  83
  84         if (row == null) {
  85             throw new IllegalArgumentException("Row cannot be null");
  86         }
  87
  88         T removed = getSelectedRow();
  89         if (selectByHandle(grid.getDataSource().getHandle(row))) {
  90             grid.fireEvent(new SelectionEvent<T>(grid, row, removed, false));
  91
  92             return true;
  93         }
  94         return false;
  95     }
  96
  97     @Override
  98     public boolean deselect(T row) {
  99
 100         if (row == null) {
 101             throw new IllegalArgumentException("Row cannot be null");
 102         }
 103
 104         if (isSelected(row)) {
 105             deselectByHandle(selectedRow);
 106             grid.fireEvent(new SelectionEvent<T>(grid, null, row, false));
 107             return true;
 108         }
 109
 110         return false;
 111     }
 112
 113     @Override
 114     public T getSelectedRow() {
 115         return (selectedRow != null ? selectedRow.getRow() : null);
 116     }
 117
 118     @Override
 119     public void reset() {
 120         if (selectedRow != null) {
 121             deselect(getSelectedRow());
 122         }
 123     }
 124
 125     @Override
 126     public Collection<T> getSelectedRows() {
 127         if (getSelectedRow() != null) {
 128             return Collections.singleton(getSelectedRow());
 129         }
 130         return Collections.emptySet();
 131     }
 132
 133     @Override
 134     protected boolean selectByHandle(RowHandle<T> handle) {
 135         if (handle != null && !handle.equals(selectedRow)) {
 136             deselectByHandle(selectedRow);
 137             selectedRow = handle;
 138             selectedRow.pin();
 139             return true;
 140         } else {
 141             return false;
 142         }
 143     }
 144
 145     @Override
 146     protected boolean deselectByHandle(RowHandle<T> handle) {
 147         if (handle != null && handle.equals(selectedRow)) {
 148             selectedRow.unpin();
 149             selectedRow = null;
 150             return true;
 151         } else {
 152             return false;
 153         }
 154     }
 155
 156     @Override
 157     public void setDeselectAllowed(boolean deselectAllowed) {
 158         this.deselectAllowed = deselectAllowed;
 159         updateHandlerDeselectAllowed();
 160     }
 161
 162     @Override
 163     public boolean isDeselectAllowed() {
 164         return deselectAllowed;
 165     }
 166
 167     private void updateHandlerDeselectAllowed() {
 168         if (spaceSelectHandler != null) {
 169             spaceSelectHandler.setDeselectAllowed(deselectAllowed);
 170         }
 171         if (clickSelectHandler != null) {
 172             clickSelectHandler.setDeselectAllowed(deselectAllowed);
 173         }
 174     }
 175
 176     @Override
 177     public boolean isUserSelectionAllowed() {
 178         return userSelectionAllowed;
 179     }
 180
 181     @Override
 182     public void setUserSelectionAllowed(boolean userSelectionAllowed) {
 183         this.userSelectionAllowed = userSelectionAllowed;
 184     }
 185 }