src/org/eclipse/jdt/annotation/NonNullByDefault.java

   1 /*******************************************************************************
   2  * Copyright (c) 2011 Stephan Herrmann and others.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * which accompanies this distribution, and is available at
   6  * http://www.eclipse.org/legal/epl-v10.html
   7  *
   8  * Contributors:
   9  *     Stephan Herrmann - initial API and implementation
  10  *     IBM Corporation - bug fixes
  11  *******************************************************************************/
  12 package org.eclipse.jdt.annotation;
  13
  14 import static java.lang.annotation.ElementType.CONSTRUCTOR;
  15 import static java.lang.annotation.ElementType.METHOD;
  16 import static java.lang.annotation.ElementType.PACKAGE;
  17 import static java.lang.annotation.ElementType.TYPE;
  18
  19 import java.lang.annotation.Documented;
  20 import java.lang.annotation.Retention;
  21 import java.lang.annotation.RetentionPolicy;
  22 import java.lang.annotation.Target;
  23
  24 /**
  25  * This annotation can be applied to a package, type, method or constructor in order to
  26  * define that all contained entities for which a null annotation is otherwise lacking
  27  * should be considered as {@link NonNull @NonNull}.
  28  * <dl>
  29  * <dt>Canceling a default</dt>
  30  * <dd>By using a <code>@NonNullByDefault</code> annotation with the argument <code>false</code>,
  31  * a default from any enclosing scope can be canceled for the element being annotated.
  32  * <dt>Nested defaults</dt>
  33  * <dd>If a <code>@NonNullByDefault</code>
  34  * annotation is used within the scope of another <code>@NonNullByDefault</code>
  35  * annotation or a project-wide default setting, the innermost annotation defines the
  36  * default applicable at any given position (depending on the parameter {@link #value()}).</dd>
  37  * </dl>
  38  * Note that for applying an annotation to a package, a file by the name
  39  * <code>package-info.java</code> is used.
  40  *
  41  * @since 1.0
  42  */
  43 @Documented
  44 @Retention(RetentionPolicy.CLASS)
  45 @Target({ PACKAGE, TYPE, METHOD, CONSTRUCTOR })
  46 public @interface NonNullByDefault {
  47         /**
  48          * When parameterized with <code>false</code>, the annotation specifies that the current element should not apply
  49          * any default to un-annotated types.
  50          */
  51         boolean value() default true;
  52 }