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Diffstat (limited to 'src/core/lombok/experimental/Builder.java')
| -rw-r--r-- | src/core/lombok/experimental/Builder.java | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/src/core/lombok/experimental/Builder.java b/src/core/lombok/experimental/Builder.java new file mode 100644 index 00000000..b6667462 --- /dev/null +++ b/src/core/lombok/experimental/Builder.java @@ -0,0 +1,112 @@ +/* + * Copyright (C) 2013 The Project Lombok Authors. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ +package lombok.experimental; + +import static java.lang.annotation.ElementType.*; +import static java.lang.annotation.RetentionPolicy.*; + +import java.lang.annotation.Retention; +import java.lang.annotation.Target; + +/** + * The builder annotation creates a so-called 'builder' aspect to the class that is annotated or the class + * that contains a member which is annotated with {@code @Builder}. + * <p> + * If a member is annotated, it must be either a constructor or a static method. If a class is annotated, + * then a private constructor is generated with all fields as arguments + * (as if {@code @AllArgsConstructor(AccessLevel.PRIVATE)} is present + * on the class), and it is as if this constructor has been annotated with {@code @Builder} instead. + * <p> + * The effect of {@code @Builder} is that an inner class is generated named <code><strong>T</strong>Builder</code>, + * with a private constructor. Instances of <code><strong>T</strong>Builder</code> are made with the static + * method named {@code builder()} which is also generated for you in the class itself (not in the builder class). + * <p> + * The <code><strong>T</strong>Builder</code> class contains 1 method for each parameter of the annotated + * constructor / static method (each field, when annotating a class), which returns the builder itself. + * The builder also has a <code>build()</code> method which returns a completed instance of the original type, + * created by passing all parameters as set via the various other methods in the builder to the constructor + * or static method that was annotated with {@code @Builder}. The return type of this method will be the same + * as the relevant class, unless a static method has been annotated, in which case it'll be equal to the + * return type of that method. + * <p> + * Complete documentation is found at <a href="http://projectlombok.org/features/experimental/Builder.html">the project lombok features page for @Builder</a>. + * <p> + * <p> + * Before: + * + * <pre> + * @Builder + * class Example { + * private int foo; + * private final String bar; + * } + * </pre> + * + * After: + * + * <pre> + * class Example<T> { + * private T foo; + * private final String bar; + * + * private Example(T foo, String bar) { + * this.foo = foo; + * this.bar = bar; + * } + * + * public static <T> ExampleBuilder<T> builder() { + * return new ExampleBuilder<T>(); + * } + * + * public static class ExampleBuilder<T> { + * private T foo; + * private String bar; + * + * private ExampleBuilder() {} + * + * public ExampleBuilder foo(T foo) { + * this.foo = foo; + * return this; + * } + * + * public ExampleBuilder bar(String bar) { + * this.bar = bar; + * return this; + * } + * + * @java.lang.Override public String toString() { + * return "ExampleBuilder(foo = " + foo + ", bar = " + bar + ")"; + * } + * + * public Example build() { + * return new Example(foo, bar); + * } + * } + * } + * </pre> + */ +@Target({TYPE, METHOD, CONSTRUCTOR}) +@Retention(SOURCE) +public @interface Builder { + /** Name of the static method that creates a new builder instance. Default: {@code builder}. */ + String builderMethodName() default "builder"; +} |