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| author | Reinier Zwitserloot <reinier@zwitserloot.com> | 2013-07-22 23:23:46 +0200 |
|---|---|---|
| committer | Reinier Zwitserloot <reinier@zwitserloot.com> | 2013-07-22 23:23:46 +0200 |
| commit | 45697b50816df79475a8bb69dc89ff68747fbfe6 (patch) | |
| tree | 25cb023eec1f74baf5063cc5a58a5351ee43d6f0 /website/features/experimental/Builder.html | |
| parent | 4c03e3d220900431085897878d4888bf530b31ec (diff) | |
| parent | deed98be16e5099af52d951fc611f86a82a42858 (diff) | |
| download | lombok-45697b50816df79475a8bb69dc89ff68747fbfe6.tar.gz lombok-45697b50816df79475a8bb69dc89ff68747fbfe6.tar.bz2 lombok-45697b50816df79475a8bb69dc89ff68747fbfe6.zip | |
Merge branch 'master' into jdk8. Also added some major fixes whilst merging.
Conflicts:
src/core/lombok/javac/handlers/JavacHandlerUtil.java
src/utils/lombok/javac/CommentCatcher.java
src/utils/lombok/javac/Javac.java
Diffstat (limited to 'website/features/experimental/Builder.html')
| -rw-r--r-- | website/features/experimental/Builder.html | 134 |
1 files changed, 134 insertions, 0 deletions
diff --git a/website/features/experimental/Builder.html b/website/features/experimental/Builder.html new file mode 100644 index 00000000..0616afc9 --- /dev/null +++ b/website/features/experimental/Builder.html @@ -0,0 +1,134 @@ +<!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>EXPERIMENTAL - @Builder</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>@Builder</h1> + <div class="byline">... and Bob's your uncle: No-hassle fancy-pants APIs for object creation!</div> + <div class="since"> + <h3>Since</h3> + <p> + @Builder was introduced as experimental feature in lombok v0.12.0. + </p> + </div> + <div class="experimental"> + <h3>Experimental</h3> + <p> + Experimental because: + <ul> + <li>New feature - community feedback requested.</li> + </ul> + Current status: <em>sure thing</em> - This feature will move to the core package soon. + </div> + <div class="overview"> + <h3>Overview</h3> + <p> + The <code>@Builder</code> annotation produces complex builder APIs for your classes. + </p><p> + <code>@Builder</code> lets you automatically produce the code required to have your class be instantiable with code such as:<br /> + <code>Person.builder().name("Adam Savage").city("San Francisco").worksAt("Mythbusters").build();</code> + </p><p> + <code>@Builder</code> can be placed on a class, or on a constructor, or on a static method. While the "on a class" and "on a constructor" + mode are the most common use-case, <code>@Builder</code> is most easily explained with the "static method" use-case. + </p><p> + A static method annotated with <code>@Builder</code> (from now on called the <em>target</em>) causes the following 7 things to be generated:<ul> + <li>An inner static class named <code><em>Foo</em>Builder</code>, with the same type arguments as the static method (called the <em>builder</em>).</li> + <li>In the <em>builder</em>: One private non-static non-final field for each parameter of the <em>target</em>.</li> + <li>In the <em>builder</em>: A package private no-args empty constructor.</li> + <li>In the <em>builder</em>: A 'setter'-like method for each parameter of the <em>target</em>: It has the same type as that parameter and the same name. + It returns the builder itself, so that the setter calls can be chained, as in the above example.</li> + <li>In the <em>builder</em>: A <code>build()</code> method which calls the static method, passing in each field. It returns the same type that the + <em>target</em> returns.</li> + <li>In the <em>builder</em>: A sensible <code>toString()</code> implementation.</li> + <li>In the class containing the <em>target</em>: A <code>builder()</code> method, which creates a new instance of the <em>builder</em>.</li> + </ul> + Each listed generated element will be silently skipped if that element already exists (disregarding parameter counts and looking only at names). This + includes the <em>builder</em> itself: If that class already exists, lombok will simply start injecting fields and methods inside this already existing + class, unless of course the fields / methods to be injected already exist. You may not put any other method (or constructor) generating lombok annotation + on a builder class though; for example, you can not put <code>@EqualsAndHashCode</code> on the builder class. + </p><p> + Now that the "static method" mode is clear, putting a <code>@Builder</code> annotation on a constructor functions similarly; effectively, + constructors are just static methods that have a special syntax to invoke them: Their 'return type' is the class they construct, and their + type parameters are the same as the type parameters of the class itself. + </p><p> + Finally, applying <code>@Builder</code> to a class is as if you added <code>@AllArgsConstructor(access = AccessLevel.PACKAGE)</code> to the class and applied the + <code>@Builder</code> annotation to this all-args-constructor. This only works if you haven't written any explicit constructors yourself. If you do have an + explicit constructor, put the <code>@Builder</code> annotation on the constructor instead of on the class. + </p><p> + The name of the builder class is <code><em>Foobar</em>Builder</code>, where <em>Foobar</em> is the simplified, title-cased form of the return type of the + <em>target</em> - that is, the name of your type for <code>@Builder</code> on constructors and types, and the name of the return type for <code>@Builder</code> + on static methods. For example, if <code>@Builder</code> is applied to a class named <code>com.yoyodyne.FancyList<T></code>, then the builder name will be + <code>FancyListBuilder<T></code>. If <code>@Builder</code> is applied to a static method that returns <code>void</code>, the builder will be named + <code>VoidBuilder</code>. + </p><p> + The configurable aspects of builder are:<ul> + <li>The <em>builder's class name</em> (default: return type + 'Builder')</li> + <li>The <em>build()</em> method's name (default: <code>"build"</code>)</li> + <li>The <em>builder()</em> method's name (default: <code>"builder"</code>)</li> + <li>The 'fluent' nature of the generated 'setter'-like methods. A fluent 'setter' is named just <code>fieldName()</code>, a non-fluent one is named <code>setFieldName()</code>. (default: <code>true</code>)</li> + <li>The 'chain' nature of the generated 'setter'-like methods. A chainable 'setter' returns the builder object itself, letting you chain 'set' calls. A non-chainable setter returns <code>void</code>. (default: <code>true</code>)</li> + </ul> + Example usage where all options are changed from their defaults:<br /> + <code>@Builder(builderClassName = "HelloWorldBuilder", buildMethodName = "execute", builderMethodName = "helloWorld", fluent = false, chain = false)</code><br /> + </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"> + <h3>Small print</h3><div class="smallprint"> + <p> + Another strategy for fluent APIs is that the programmer using your library statically imports your 'builder' method. In this case, you might want to name your builder + method equal to your type's name. So, the builder method for a class called <code>Person</code> would become <code>person()</code>. This is nicer if the builder method + is statically imported. + </p><p> + If the return type of your target static method is a type parameter (such as <code>T</code>), lombok will enforce an explicit builder class name. + </p><p> + You don't HAVE to use <code>@Builder</code> to build anything; you can for example put it on a static method that has lots of parameter to improve the API of it. + In this case, we suggest you use <code>buildMethodName = </code> to rename the build method to <code>execute()</code> instead. + </p><p> + The builder class will NOT get an auto-generated implementation of <code>hashCode</code> or <code>equals</code> methods! These would suggest that it is sensible to use + instances of a builder as keys in a set or map. However, that's not a sensible thing to do. Hence, no <code>hashCode</code> or <code>equals</code>. + </p><p> + Generics are sorted out for you. + </p><p> + If an explicit constructor is present, but <code>@Builder</code> is placed on the class, then the builder will be generated as if an explicit constructor is present with the + same arguments list as what <code>@AllArgsConstructor</code> would produce. If this constructor does not exist, a compile time error will result. Usually you should just either let + lombok make this constructor (delete your constructor from the source), or, move the <code>@Builder</code> annotation to the constructor. + </p> + </div> + </div> + <div class="footer"> + <a href="index.html">Back to experimental features</a> | <span class="disabled">Previous feature</span> | <a href="Accessors.html">Next feature (@Accessors)</a><br /> + <a href="../../credits.html" class="creditsLink">credits</a> | <span class="copyright">Copyright © 2009-2013 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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