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1   /*
2    * *************************************************************************************************************************************************************
3    *
4    * SteelBlue: DCI User Interfaces
5    * http://tidalwave.it/projects/steelblue
6    *
7    * Copyright (C) 2015 - 2025 by Tidalwave s.a.s. (http://tidalwave.it)
8    *
9    * *************************************************************************************************************************************************************
10   *
11   * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
12   * You may obtain a copy of the License at
13   *
14   *     http://www.apache.org/licenses/LICENSE-2.0
15   *
16   * 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
17   * CONDITIONS OF ANY KIND, either express or implied.  See the License for the specific language governing permissions and limitations under the License.
18   *
19   * *************************************************************************************************************************************************************
20   *
21   * git clone https://bitbucket.org/tidalwave/steelblue-src
22   * git clone https://github.com/tidalwave-it/steelblue-src
23   *
24   * *************************************************************************************************************************************************************
25   */
26  package it.tidalwave.ui.core.function;
27  
28  import jakarta.annotation.Nonnull;
29  import java.beans.PropertyChangeEvent;
30  import java.beans.PropertyChangeListener;
31  import it.tidalwave.ui.core.ChangingSource;
32  
33  /***************************************************************************************************************************************************************
34   *
35   * @since   2.0-ALPHA-1
36   * @author  Fabrizio Giudici
37   *
38   **************************************************************************************************************************************************************/
39  @SuppressWarnings("this-escape")
40  public abstract class BooleanBoundFunctionSupport extends BoundFunctionSupport<Boolean, Boolean>
41    {
42      protected final ChangingSource<Boolean>[] sources;
43  
44      private boolean oldValue;
45  
46      private boolean newValue;
47  
48      private final PropertyChangeListener pcl = new PropertyChangeListener()
49        {
50          @Override
51          public void propertyChange (@Nonnull final PropertyChangeEvent event)
52            {
53              newValue = function();
54              fireValueChanged(oldValue, newValue);
55              oldValue = newValue;
56            }
57        };
58  
59      public BooleanBoundFunctionSupport (@Nonnull final ChangingSource<Boolean> ... sources)
60        {
61          this.sources = sources;
62  
63          for (final var source : sources)
64            {
65              source.addPropertyChangeListener(pcl);
66            }
67  
68          oldValue = function();
69        }
70  
71      protected abstract boolean function();
72  
73      @Override @Nonnull
74      public final Boolean get()
75        {
76          return newValue;
77        }
78    }