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
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
<!DOCTYPE html>
<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<link rel="stylesheet" type="text/css" href="../../logi/reset.css" />
<link rel="stylesheet" type="text/css" href="../features.css" />
<link rel="shortcut icon" href="../../favicon.ico" type="image/x-icon" />
<meta name="description" content="Spice up your java" />
<title>onX</title>
</head><body><div id="pepper">
<div class="minimumHeight"></div>
<div class="meat">
<div class="header"><a href="../../index.html">Project Lombok</a></div>
<h1>onX</h1>
<div class="byline">Sup dawg, we heard you like annotations, so we put annotations in your annotations so you can annotate while you're annotating.</div>
<div class="since">
<h3>Since</h3>
<p>
onX was introduced as experimental feature in lombok v0.11.7 (<a href="/download-edge.html">edge release only</a>).
</p>
</div>
<div class="experimental">
<h3>Experimental</h3>
<p>
Experimental because:
<ul>
<li>Ugly syntax. The syntax of this feature is not optimal, but it is the least convoluted syntax that could possibly work (for now!)</li>
<li>Possibly java 9 will offer (much) better ways of supporting this feature.</li>
<li>Uncertainty: Future versions of javac may break this feature, and we may not be able to restore it.</li>
</ul>
Current status: <em>uncertain</em> - Currently we feel this feature cannot move out of experimental status.
</div>
<div class="overview">
<h3>Overview</h3>
<p>
<strong>This feature is considered 'workaround status' - it exists in order to allow users of lombok that cannot work without this feature to have access to it anyway. If we find a better way to implement this feature, or some future java version introduces an alternative strategy, this feature can disappear without a reasonable deprecation period. Also, this feature may not work in future versions of javac. Use at your own discretion.</strong>
</p><p>
Most annotations that make lombok generate methods or constructors can be configured to also make lombok put custom annotations on elements in the generated code.
</p><p>
<code>@Getter</code>, <code>@Setter</code>, and <code>@Wither</code> support the <code>onMethod</code> option, which will put the listed annotations on the generated method.
</p><p>
<code>@AllArgsConstructor</code>, <code>@NoArgsConstructor</code>, and <code>@RequiredArgsConstructor</code> support the <code>onConstructor</code> option which will put the listed annotations on the generated constructor.
</p><p>
<code>@Setter</code> and <code>@Wither</code> support <code>onParam</code> in addition to <code>onMethod</code>; annotations listed will be put on the only parameter that the generated method has.
</p><p>
The syntax is a little strange; to use any of the 3 <code>onX</code> features, you must wrap the annotations to be applied to the constructor / method / parameter in <code>@_(@AnnotationGoesHere)</code>. To apply multiple annotations, use <code>@_({@Annotation1, @Annotation2})</code>. The annotations can themselves obviously have parameters as well.
</p>
</div>
<div class="snippets">
<div class="pre">
<h3>With Lombok</h3>
<div class="snippet">@HTML_PRE@</div>
</div>
<div class="sep"></div>
<div class="post">
<h3>Vanilla Java</h3>
<div class="snippet">@HTML_POST@</div>
</div>
</div>
<div style="clear: left;"></div>
<div class="overview">
<h3>Small print</h3><div class="smallprint">
<p>
The reason of the weird syntax is to make this feature work in javac 7 compilers; the <code>@_</code> type is an annotation reference to the annotation type <code>_</code> (underscore) which doesn't actually exist; this makes javac 7 delay aborting the compilation process due to an error because it is possible an annotation processor will later create the <code>_</code> type. Instead, lombok applies the annotations and removes the references so that the error will never actually occur. The point is: The <code>_</code> type <em>must not exist</em>, otherwise the feature does not work. In the rare case that the <code>_</code> type does exist (and is imported or in the package), you can simply add more underscores. Technically any non-existent type would work, but to maintain consistency and readability and catch erroneous use, lombok considers it an error if the 'wrapper' annotation is anything but a series of underscores.
</p><p>
To reiterate: This feature can disappear at any time; if you use this feature, be prepared to adjust your code when we find a nicer way of implementing this feature, or, if a future version of javac forces us to remove this feature entirely with no alternative.
</p><p>
The <code>onX</code> parameter is not legal on any type-wide variant. For example, a <code>@Getter</code> annotation on a class does not support <code>onMethod</code>.
</p>
</div>
</div>
<div class="footer">
<a href="index.html">Back to experimental features</a> | <a href="Wither.html">Previous feature (@Wither)</a> | <span class="disabled">Next feature</span><br />
<a href="../../credits.html" class="creditsLink">credits</a> | <span class="copyright">Copyright © 2009-2013 The Project Lombok Authors, licensed under the <a href="http://www.opensource.org/licenses/mit-license.php">MIT license</a>.</span>
</div>
<div style="clear: both;"></div>
</div>
</div>
<script type="text/javascript">
var gaJsHost = (("https:" == document.location.protocol) ? "https://ssl." : "http://www.");
document.write(unescape("%3Cscript src='" + gaJsHost + "google-analytics.com/ga.js' type='text/javascript'%3E%3C/script%3E"));
</script>
<script type="text/javascript">
try {
var pageTracker = _gat._getTracker("UA-9884254-1");
pageTracker._trackPageview();
} catch(err) {}
</script>
</body></html>
|
