1 /*
2 * *************************************************************************************************************************************************************
3 *
4 * TheseFoolishThings: Miscellaneous utilities
5 * http://tidalwave.it/projects/thesefoolishthings
6 *
7 * Copyright (C) 2009 - 2024 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/thesefoolishthings-src
22 * git clone https://github.com/tidalwave-it/thesefoolishthings-src
23 *
24 * *************************************************************************************************************************************************************
25 */
26 package it.tidalwave.role.ui.function;
27
28 import javax.annotation.Nonnull;
29 import it.tidalwave.role.ui.Changeable;
30 import it.tidalwave.role.ui.ChangingSource;
31 import lombok.extern.slf4j.Slf4j;
32
33 /***************************************************************************************************************************************************************
34 *
35 * Changes the destination only at a certain condition in function of the target.
36 *
37 * @author Fabrizio Giudici
38 *
39 **************************************************************************************************************************************************************/
40 @Slf4j
41 public abstract class WeakCopyFunctionSupport<T> extends UnaryBoundFunctionSupport<T, T> implements Changeable<T>
42 {
43 @Nonnull
44 protected T targetValue;
45
46 public WeakCopyFunctionSupport (@Nonnull final ChangingSource<T> source)
47 {
48 super(source);
49 }
50
51 @Override
52 protected void onSourceChange (@Nonnull final T oldSourceValue, @Nonnull final T newSourceValue)
53 {
54 final var oldValue = function(oldSourceValue);
55 final var newValue = function(newSourceValue);
56
57 if (shouldChange(oldValue, newValue))
58 {
59 value = newValue;
60 fireValueChanged(oldValue, newValue);
61 }
62 }
63
64 @Override
65 public void set (final T value)
66 {
67 this.targetValue = value;
68 }
69
70 protected abstract boolean shouldChange (T oldValue, T newValue);
71
72 @Override @Nonnull
73 protected T function (@Nonnull final T value)
74 {
75 return value;
76 }
77 }