[issue #2368] [withBy] support for javac

1 files changed, 112 insertions, 0 deletions

diff --git a/src/core/lombok/experimental/WithBy.java b/src/core/lombok/experimental/WithBy.java
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+++ b/src/core/lombok/experimental/WithBy.java
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+/*
+ * Copyright (C) 2020 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 java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import lombok.AccessLevel;
+
+/**
+ * Put on any field to make lombok build a 'withBy' - a withFieldNameBy method which produces a clone of this object (except for 1 field which gets a new value).
+ * <p>
+ * Complete documentation is found at <a href="https://projectlombok.org/features/experimental/WithBy">the project lombok features page for &#64;WithBy</a>.
+ * <p>
+ * Example:
+ * <pre>
+ *     private &#64;WithBy final int foo;
+ *     private &#64;WithBy final String bar;
+ * </pre>
+ * 
+ * will generate:
+ * 
+ * <pre>
+ *     public SELF_TYPE withFooBy(@lombok.NonNull IntUnaryOperator operator) {
+ *         int foo = operator.apply(this.foo);
+ *         return this.foo == foo ? this : new SELF_TYPE(foo, bar);
+ *     }
+ *     public SELF_TYPE withBarBy(@lombok.NonNull Function&lt;? super String, ? extends String&gt; operator) {
+ *         String bar = operator.apply(this.bar);
+ *         return this.bar == bar ? this : new SELF_TYPE(foo, bar);
+ *     }
+ * </pre>
+ * <p>
+ * This annotation can also be applied to a class, in which case it'll be as if all non-static fields that don't already have
+ * a {@code WithBy} annotation have the annotation.
+ * <p>
+ * This annotation is primarily useful for hierarchical immutable data structures. For example:
+ * 
+ * <pre>
+ *     class Movie {
+ *         &#64;WithBy private final Director director;
+ *     }
+ *     
+ *     class Director {
+ *         &#64;WithBy private final LocalDate birthDate;
+ *     }
+ * </pre>
+ * 
+ * Using plain old {@code @With}, to increment a movie's director's birth date by one, you would write:
+ * 
+ * <pre>
+ *     movie = movie.withDirector(movie.getDirector().withBirthDate(movie.getDirector().getBirthDate().plusDays(1)));
+ * </pre>
+ * 
+ * but with {@code @WithBy}, you'd write:
+ * 
+ * <pre>
+ *     movie = movie.withDirectorBy(d -> d.withBirthDateBy(bd -> bd.plusDays(1)));
+ * </pre>
+ */
+@Target({ElementType.FIELD, ElementType.TYPE})
+@Retention(RetentionPolicy.SOURCE)
+public @interface WithBy {
+	/**
+	 * If you want your with method to be non-public, you can specify an alternate access level here.
+	 * 
+	 * @return The method will be generated with this access modifier.
+	 */
+	AccessLevel value() default AccessLevel.PUBLIC;
+	
+	/**
+	 * Any annotations listed here are put on the generated method.
+	 * The syntax for this feature depends on JDK version (nothing we can do about that; it's to work around javac bugs).<br>
+	 * up to JDK7:<br>
+	 *  {@code @With(onMethod=@__({@AnnotationsGoHere}))}<br>
+	 * from JDK8:<br>
+	 *  {@code @With(onMethod_={@AnnotationsGohere})} // note the underscore after {@code onMethod}.
+	 * 
+	 * @return List of annotations to apply to the generated method.
+	 */
+	AnyAnnotation[] onMethod() default {};
+	
+	/**
+	  * Placeholder annotation to enable the placement of annotations on the generated code.
+	  * @deprecated Don't use this annotation, ever - Read the documentation.
+	  */
+	@Deprecated
+	@Retention(RetentionPolicy.SOURCE)
+	@Target({})
+	@interface AnyAnnotation {}
+}