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<div class="header"><a href="../index.html">Project Lombok</a></div>
<h1>@Value</h1>
<div class="byline">Immutable classes made very easy.</div>
<div class="since">
<h3>Since</h3>
<p>
<code>@Value</code> was introduced as experimental feature in lombok v0.11.4.
</p><p>
<code>@Value</code> no longer implies <code>@Wither</code> since lombok v0.11.8.
</p><p>
<code>@Value</code> promoted to the main <code>lombok</code> package since lombok v0.12.0.
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<h3>Overview</h3>
<p>
<code>@Value</code> is the immutable variant of <a href="Data.html"><code>@Data</code></a>; all fields are made <code>private</code> and <code>final</code> by default, and setters are not generated. The class itself is also made <code>final</code> by default, because immutability is not something that can be forced onto a subclass. Like <code>@Data</code>, useful <code>toString()</code>, <code>equals()</code> and <code>hashCode()</code> methods are also generated, each field gets a getter method, and a constructor that covers every
argument (except <code>final</code> fields that are initialized in the field declaration) is also generated.
</p><p>
In practice, <code>@Value</code> is shorthand for: <code>final @ToString @EqualsAndHashCode @AllArgsConstructor @FieldDefaults(makeFinal = true, level = AccessLevel.PRIVATE) @Getter</code>.
</p><p>
It is possible to override the final-by-default and private-by-default behaviour using either an explicit access level on a field, or by using the <code>@NonFinal</code> or <code>@PackagePrivate</code> annotations.<br />
It is possible to override any default behaviour for any of the 'parts' that make up <code>@Value</code> by explicitly using that annotation.
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<h3>With Lombok</h3>
<div class="snippet">@HTML_PRE@</div>
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<h3>Vanilla Java</h3>
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<h3>Small print</h3><div class="smallprint">
<p>
Look for the documentation on the 'parts' of <code>@Value</code>: <a href="ToString.html"><code>@ToString</code></a>, <a href="EqualsAndHashCode.html"><code>@EqualsAndHashCode</code></a>, <a href="Constructor.html"><code>@AllArgsConstructor</code></a>, <a href="experimental/FieldDefaults.html"><code>@FieldDefaults</code></a>, and <a href="GetterSetter.html"><code>@Getter</code></a>.
</p><p>
For classes with generics, it's useful to have a static method which serves as a constructor, because inference of generic parameters via static methods works in java6 and avoids having to use the diamond operator. While you can force this by applying an explicit <code>@AllArgsConstructor(staticConstructor="of")</code> annotation, there's also the <code>@Value(staticConstructor="of")</code> feature, which will make the generated all-arguments constructor private, and generates a public static method named <code>of</code> which is a wrapper around this private constructor.
</p><p>
<code>@Value</code> was an experimental feature from v0.11.4 to v0.11.9 (as <code>@lombok.experimental.Value</code>). It has since been moved into the core package. The old annotation is still
around (and is an alias). It will eventually be removed in a future version, though.
</p><p>
It is not possible to use <code>@FieldDefaults</code> to 'undo' the private-by-default and final-by-default aspect of fields in the annotated class. Use <code>@NonFinal</code> and <code>@PackagePrivate</code> on the fields in the class to override this behaviour.
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