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Reinier Zwitserloot
77 lines
3.7 KiB
HTML
77 lines
3.7 KiB
HTML
<!DOCTYPE html>
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<html><head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
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<link rel="stylesheet" type="text/css" href="../logi/reset.css" />
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<link rel="stylesheet" type="text/css" href="features.css" />
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<link rel="shortcut icon" href="../favicon.ico" type="image/x-icon" />
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<meta name="description" content="Spice up your java" />
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<title>val</title>
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</head><body><div id="pepper">
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<div class="minimumHeight"></div>
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<div class="meat">
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<div class="header"><a href="../index.html">Project Lombok</a></div>
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<h1>val</h1>
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<div class="byline">Finally! Hassle-free final local variables.</div>
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<div class="overview">
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<h3>Overview</h3>
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<p>
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<em>NEW in Lombok 0.10: </em>You can use <code>val</code> as the type of a local variable declaration instead of actually writing the type. When you do this,
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the type will be inferred from the initializer expression. The local variable will also be made final. This feature works
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on local variables and on foreach loops only, not on fields. The initializer expression is required.
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</p><p>
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<code>val</code> is actually a 'type' of sorts, and exists as a real class in the <code>lombok</code> package. You must import it for val to work (or use <code>lombok.val</code> as the type).
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The existence of this type on a local variable declaration triggers both the adding of the <code>final</code> keyword as well as copying the type of the initializing expression which overwrites
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the 'fake' <code>val</code> type.
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</p><p>
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<em>WARNING: This feature does not currently work in NetBeans. We're working on fixing that.</em>
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</p>
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</div>
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<div class="snippets">
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<div class="pre">
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<h3>With Lombok</h3>
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<div class="snippet">@HTML_PRE@</div>
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</div>
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<div class="sep"></div>
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<div class="post">
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<h3>Vanilla Java</h3>
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<div class="snippet">@HTML_POST@</div>
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</div>
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</div>
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<div style="clear: left;"></div>
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<div class="overview confKeys">
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<h3>Supported configuration keys:</h3>
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<dl>
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<dt><code>lombok.val.flagUsage</code> = [<code>warning</code> | <code>error</code>] (default: not set)</dt>
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<dd>Lombok will flag any usage of <code>val</code> as a warning or error if configured.</dd>
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</dl>
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</div>
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<div class="overview">
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<h3>Small print</h3><div class="smallprint">
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<p>
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For compound types, the most common superclass is inferred, not any shared interfaces. For example, <code>bool ? new HashSet() : new ArrayList()</code>
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is an expression with a compound type: The result is both <code>AbstractCollection</code> as well as <code>Serializable</code>. The type inferred will be
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<code>AbstractCollection</code>, as that is a class, whereas <code>Serializable</code> is an interface.
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</p><p>
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In ambiguous cases, such as when the initializer expression is <code>null</code>, <code>java.lang.Object</code> is inferred.
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</p>
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</div>
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</div>
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<div class="footer">
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<a href="index.html">Back to features</a> | <span class="disabled">Previous feature</span> | <a href="NonNull.html">Next feature (@NonNull)</a><br />
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<a href="../credits.html" class="creditsLink">credits</a> | <span class="copyright">Copyright © 2009-2015 The Project Lombok Authors, licensed under the <a href="http://www.opensource.org/licenses/mit-license.php">MIT license</a>.</span>
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