aboutsummaryrefslogtreecommitdiff
path: root/website2/templates/features/experimental/UtilityClass.html
blob: 8145437a622ff141cf581aee808801e002d6dcc9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
<#import "../_features.html" as f>

<@f.scaffold title="@UtilityClass" logline="Utility, metility, wetility! Utility classes for the masses.">
	<@f.history>
		<p>
			<code>@UtilityClass</code> was introduced as an experimental feature in lombok v1.16.2.
		</p>
	</@f.history>

	<@f.experimental>
		<ul>
			<li>Some debate as to whether its common enough to count as boilerplate.</li>
		</ul>
		Current status: <em>positive</em> - Currently we feel this feature may move out of experimental status with no or minor changes soon.
	</@f.experimental>

	<@f.overview>
		<p>
			A utility class is a class that is just a namespace for functions. No instances of it can exist, and all its members are static. For example, <code>java.lang.Math</code> and <code>java.util.Collections</code> are well known utility classes. This annotation automatically turns the annotated class into one.
		</p><p>
			A utility class cannot be instantiated. By marking your class with <code>@UtilityClass</code>, lombok will automatically generate a private constructor that throws an exception, flags as error any explicit constructors you add, and marks the class <code>final</code>. If the class is an inner class, the class is also marked <code>static</code>.
		</p><p>
			<em>All</em> members of a utility class are automatically marked as <code>static</code>. Even fields and inner classes.
		</p>
	</@f.overview>

	<@f.snippets name="experimental/UtilityClass" />

	<@f.confKeys>
		<dt>
			<code>lombok.utilityClass.flagUsage</code> = [<code>warning</code> | <code>error</code>] (default: not set)
		</dt><dd>
			Lombok will flag any usage of <code>@UtilityClass</code> as a warning or error if configured.
		</dd>
	</@f.confKeys>

	<@f.smallPrint>
		<p>
			There isn't currently any way to create non-static members, or to define your own constructor. If you want to instantiate the utility class, even only as an internal implementation detail, <code>@UtilityClass</code> cannot be used.
		</p>
	</@f.smallPrint>
</@f.scaffold>