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diff --git a/website-old/features/SneakyThrows.html b/website-old/features/SneakyThrows.html new file mode 100644 index 00000000..11937e63 --- /dev/null +++ b/website-old/features/SneakyThrows.html @@ -0,0 +1,96 @@ +<!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>@SneakyThrows</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>@SneakyThrows</h1> + <div class="byline">To boldly throw checked exceptions where no one has thrown them before!</div> + <div class="overview"> + <h3>Overview</h3> + <p> + <code>@SneakyThrows</code> can be used to sneakily throw checked exceptions without actually declaring this in your method's <code>throws</code> + clause. This somewhat contentious ability should be used carefully, of course. The code generated by lombok will not ignore, wrap, replace, + or otherwise modify the thrown checked exception; it simply fakes out the compiler. On the JVM (class file) level, all exceptions, checked or not, + can be thrown regardless of the <code>throws</code> clause of your methods, which is why this works. + </p><p> + Common use cases for when you want to opt out of the checked exception mechanism center around 2 situations:<br /><ul> + <li>A needlessly strict interface, such as <code>Runnable</code> - whatever exception propagates out of your <code>run()</code> method, + checked or not, it will be passed to the <code>Thread</code>'s unhandled exception handler. Catching a checked exception and wrapping it + in some sort of <code>RuntimeException</code> is only obscuring the real cause of the issue.</li> + <li>An 'impossible' exception. For example, <code>new String(someByteArray, "UTF-8");</code> declares that it can throw an + <code>UnsupportedEncodingException</code> but according to the JVM specification, UTF-8 <em>must</em> always be available. An + <code>UnsupportedEncodingException</code> here is about as likely as a <code>ClassNotFoundError</code> when you use a String object, + and you don't catch those either!</li></ul> + </p><p> + Be aware that it is <em>impossible</em> to catch sneakily thrown checked types directly, as javac will not let you write a catch block + for an exception type that no method call in the try body declares as thrown. This problem is not relevant in either of the use cases listed + above, so let this serve as a warning that you should not use the <code>@SneakyThrows</code> mechanism without some deliberation! + </p><p> + You can pass any number of exceptions to the <code>@SneakyThrows</code> annotation. If you pass no exceptions, you may throw any + exception sneakily. + </p><p> + <em>NOTE: </em> with lombok versions older than 0.10, unlike other lombok transformations, you need to put <strong>lombok.jar</strong> on your + classpath when you run your program. + </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.sneakyThrows.flagUsage</code> = [<code>warning</code> | <code>error</code>] (default: not set)</dt> + <dd>Lombok will flag any usage of <code>@SneakyThrows</code> as a warning or error if configured.</dd> + </dl> + </div> + <div class="overview"> + <h3>Small print</h3><div class="smallprint"> + <p> + Because <code>@SneakyThrows</code> is an implementation detail and not part of your method signature, it is an error if you try to + declare a checked exception as sneakily thrown when you don't call any methods that throw this exception. (Doing so is perfectly legal + for <code>throws</code> statements to accommodate subclasses). Similarly, <code>@SneakyThrows</code> does not inherit. + </p><p> + For the nay-sayers in the crowd: Out of the box, Eclipse will offer a 'quick-fix' for uncaught exceptions that wraps the offending + statement in a try/catch block with just <code>e.printStackTrace()</code> in the catch block. This is so spectacularly non-productive + compared to just sneakily throwing the exception onwards, that Roel and Reinier feel more than justified in claiming that the + checked exception system is far from perfect, and thus an opt-out mechanism is warranted. + </p><p> + If you put <code>@SneakyThrows</code> on a constructor, any call to a sibling or super constructor is <em>excluded</em> from the <code>@SneakyThrows</code> treatment. This is a + java restriction we cannot work around: Calls to sibling/super constructors MUST be the first statement in the constructor; they cannot be placed inside try/catch blocks. + </p><p> + <code>@SneakyThrows</code> on an empty method, or a constructor that is empty or only has a call to a sibling / super constructor results in no try/catch block and a warning. + </div> + </div> + <div class="footer"> + <a href="index.html">Back to features</a> | <a href="Builder.html">Previous feature (@Builder)</a> | <a href="Synchronized.html">Next feature (@Synchronized)</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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