/*******************************************************************************
* Copyright (c) 2011 Stephan Herrmann.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Stephan Herrmann - initial API and implementation
*******************************************************************************/
package org.eclipse.jdt.annotation;
import static java.lang.annotation.ElementType.LOCAL_VARIABLE;
import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.ElementType.PARAMETER;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* <blockquote> This annotation is intended for use by the Eclipse Java Compiler
* in order to support intra-procedural null analysis. Please see the original
* <a href="http://bugs.eclipse.org/bugs/186342">Bug 186342- [compiler][null]
* Using annotations for null checking</a> and the <a
* href="http://wiki.eclipse.org/JDT_Core/Null_Analysis">Wiki page</a> for
* status and availability of the implementation of these analyses.
* </blockquote>
* <p>
* Qualifier for a type in a method signature or a local variable declaration.
* The entity (return value, parameter, local variable) whose type has this
* annotation can never have the value <code>null</code> at runtime.
* <p>
* This has two consequences:
* <ol>
* <li>Dereferencing the entity is safe, i.e., no
* <code>NullPointerException</code> can occur at runtime.</li>
* <li>An attempt to bind a <code>null</code> value to the entity is a compile
* time error.</li>
* </ol>
* For the second case diagnostics issued by the compiler should distinguish
* three situations:
* <ol>
* <li>Nullness of the value can be statically determined, the entity is
* definitely bound from either of:
* <ul>
* <li>the value <code>null</code>, or</li>
* <li>an entity with a {@link Nullable @Nullable} type.</li>
* </ul>
* </li>
* <li>Nullness can not definitely be determined, because different code
* branches yield different results.</li>
* <li>Nullness can not be determined, because other program elements are
* involved for which null annotations are lacking.</li>
* </ol>
* </p>
*
* @author stephan
*/
@Retention(RetentionPolicy.CLASS)
@Target({ METHOD, PARAMETER, LOCAL_VARIABLE })
public @interface NonNull {
}