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| author | Reinier Zwitserloot <reinier@tipit.to> | 2009-07-17 18:36:31 +0200 |
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| committer | Reinier Zwitserloot <reinier@tipit.to> | 2009-07-17 18:36:31 +0200 |
| commit | 63a4938a7da6d49ed4ef182369faffb9e43e5368 (patch) | |
| tree | 09c839e50adb6ec293ef26f345f1d4de4400bd9a /website/features/Data.html | |
| parent | 84d017e27047042c2299110fe08302840c45320d (diff) | |
| download | lombok-63a4938a7da6d49ed4ef182369faffb9e43e5368.tar.gz lombok-63a4938a7da6d49ed4ef182369faffb9e43e5368.tar.bz2 lombok-63a4938a7da6d49ed4ef182369faffb9e43e5368.zip | |
Added documentation for the @Data annotation. Also fixed whitespace issues in the snippet views, and removed a debug print in one of the snippets.
Diffstat (limited to 'website/features/Data.html')
| -rw-r--r-- | website/features/Data.html | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/website/features/Data.html b/website/features/Data.html new file mode 100644 index 00000000..3a9697cc --- /dev/null +++ b/website/features/Data.html @@ -0,0 +1,77 @@ +<!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>@Data</title> + <!--[if lt IE 7]><script type="text/javascript" src="logi/iepngfix_tilebg.js"></script><![endif]--> +</head><body><div id="pepper"> + <div class="meat"> + <div class="minimumHeight"></div> + <div class="header"><a href="../index.html">Project Lombok</a></div> + <h1>@Data</h1> + <div class="overview"> + <h3>Overview</h3> + <p> + Any class definition may be annotated with <code>@Data</code> to let lombok generate all the boilerplate that is associated with simple POJOs + (Plain Old Java Objects) and beans: getters for all fields, setters for all non-final fields, a useful <code>toString</code>, and implementations + of <code>hashCode</code> and <code>equals</code> which consider any two objects of this type with the same values for each field as equal. A + constructor is also generated containing 1 parameter for each final field, in the order the fields are defined. This constructor simply assigns + each parameter to the appropriate field. + </p> + <p> + To override the access level of any getter/setter for any field, annotate the field with a <code>@Setter</code> or <code>@Getter</code> annotation + with the appropriate <code>AccessLevel</code> value. See the example below. For more information on how the getters/setters are generated, + see the documentation for <a href="GetterSetter.html"><code>@Getter</code> and <code>@Setter</code></a>. + </p><p> + All fields marked as <code>transient</code> will not be considered for <code>hashCode</code> and <code>equals</code>. All static fields will be + skipped entirely (not considered for any of the generated methods, and no setter/getter will be made for them). + The generated getter/setter method will be <code>public</code> unless you explicitly specify an <code>AccessLevel</code>, as shown in the example below. + Legal access levels are <code>PUBLIC</code>, <code>PROTECTED</code>, <code>PACKAGE</code>, and <code>PRIVATE</code>. + </p><p> + If any method that would normally be generated exists <em>in name</em> that method will not be generated, and no warning or error is emitted. For example, + if you already have a method with signature <code>void hashCode(int a, int b, int c)</code>, no <code>int hashCode()</code> method will be generated, + even though technically <code>int hashCode()</code> is an entirely different method. The same rule applies to the constructor, <code>toString</code>, + <code>hashCode</code>, and all getters and setters. + </p><p> + <code>@Data</code> can handle generics parameters for fields just fine. In order to reduce the boilerplate when constructing objects for classes with + generics, you can use the <code>staticConstructor</code> parameter to generate a private constructor, as well as a static method that returns a new + instance. This way, javac will infer the variable name. Thus, by declaring like so: <code>@Data(staticConstructor="of") class Foo<T> { private T x;}</code> + you can create new instances of <code>Foo</code> by writing: <code>Foo.of(5);</code> instead of having to write: <code>new Foo<Integer>(5);</code>. + </p> + <h3>Small print</h3><div class="smallprint"> + <p> + Arrays are 'deep' compared/printed/hashCoded, which means that arrays that contain themselves will result in <code>StackOverflowError</code>s. However, + this behaviour is no different from e.g. <code>ArrayList</code>. + </p><p> + You may safely presume that the hashCode implementation used will not change between versions of lombok, however this guarantee is not set in stone; + if there's a significant performance improvement to be gained from using an alternate hash algorithm, that will be substituted in a future version. + </p><p> + For a general idea of how lombok generated the <code>equals</code>, <code>hashCode</code>, and <code>toString</code> methods, check the example below. + </p><p> + For the purposes of equality, 2 <code>NaN</code> (not a number) values for floats and doubles are considered equal, eventhough 'NaN == NaN' would + return false. This is analogous to <code>java.lang.Double</code>'s equals method, and is in fact required to ensure that comparing an object + to an exact copy of itself returns <code>true</code> for equality. + </p> + </div> + </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> + <footer> + <a href="features.html">Back to features</a> | <a href="GetterSetter.html">Previous feature (@Getter / @Setter)</a> | <a href="Cleanup.html">Next feature (@Cleanup)</a><br /> + <span class="copyright">Copyright © 2009 Reinier Zwitserloot and Roel Spilker, licensed under the <a href="http://www.opensource.org/licenses/mit-license.php">MIT licence</a>.</span> + </footer> + <div style="clear: both;"></div> + </div> +</div></body></html> |