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diff --git a/website-old/features/Synchronized.html b/website-old/features/Synchronized.html new file mode 100644 index 00000000..b575e47c --- /dev/null +++ b/website-old/features/Synchronized.html @@ -0,0 +1,85 @@ +<!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>@Synchronized</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>@Synchronized</h1> + <div class="byline"><code>synchronized</code> done right: Don't expose your locks.</div> + <div class="overview"> + <h3>Overview</h3> + <p> + <code>@Synchronized</code> is a safer variant of the <code>synchronized</code> method modifier. Like <code>synchronized</code>, the + annotation can be used on static and instance methods only. It operates similarly to the <code>synchronized</code> keyword, but it locks + on different objects. The keyword locks on <code>this</code>, but the annotation locks on a field named <code>$lock</code>, which is private.<br /> + If the field does not exist, it is created for you. If you annotate a <code>static</code> method, the annotation locks on a static field + named <code>$LOCK</code> instead. + </p><p> + If you want, you can create these locks yourself. The <code>$lock</code> and <code>$LOCK</code> fields will of course not be generated if you + already created them yourself. You can also choose to lock on another field, by specifying it as parameter to the <code>@Synchronized</code> + annotation. In this usage variant, the fields will not be created automatically, and you must explicitly create them yourself, or an error will be emitted. + </p><p> + Locking on <code>this</code> or your own class object can have unfortunate side-effects, as other code not under your control can lock on these + objects as well, which can cause race conditions and other nasty threading-related bugs. + </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 confKeys"> + <h3>Supported configuration keys:</h3> + <dl> + <dt><code>lombok.synchronized.flagUsage</code> = [<code>warning</code> | <code>error</code>] (default: not set)</dt> + <dd>Lombok will flag any usage of <code>@Synchronized</code> as a warning or error if configured.</dd> + </dl> + </div> + <div class="overview"> + <h3>Small print</h3><div class="smallprint"> + <p> + If <code>$lock</code> and/or <code>$LOCK</code> are auto-generated, the fields are initialized with an empty <code>Object[]</code> array, and not + just a <code>new Object()</code> as most snippets showing this pattern in action use. Lombok does this because a new object is <em>NOT</em> + serializable, but 0-size array is. Therefore, using <code>@Synchronized</code> will not prevent your object from being serialized. + </p><p> + Having at least one <code>@Synchronized</code> method in your class means there will be a lock field, but if you later remove all such methods, + there will no longer be a lock field. That means your predetermined <code>serialVersionUID</code> changes. We suggest you <em>always</em> add + a <code>serialVersionUID</code> to your classes if you intend to store them long-term via java's serialization mechanism. If you do so, removing + all <code>@Synchronized</code> annotations from your method will not break serialization. + </p><p> + If you'd like to know why a field is not automatically generated when you choose your own name for the lock object: Because otherwise making a typo + in the field name will result in a <em>very</em> hard to find bug! + </p> + </div> + </div> + <div class="footer"> + <a href="index.html">Back to features</a> | <a href="SneakyThrows.html">Previous feature (@SneakyThrows)</a> | <a href="GetterLazy.html">Next feature (@Getter(lazy=true))</a><br /> + <a href="../credits.html" class="creditsLink">credits</a> | <span class="copyright">Copyright © 2009-2016 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) ? 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