[fonbot.git] / src / org / eclipse / jdt / annotation / NonNull.java

/*******************************************************************************
 * Copyright (c) 2011, 2012 Stephan Herrmann and others.
 * 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
 *     IBM Corporation - bug fixes
 *******************************************************************************/
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.Documented;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
 
/**
 * 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 cannot definitely be determined, because different code branches yield different results.</li>
 * <li>Nullness cannot be determined, because other program elements are involved for which
 *     null annotations are lacking.</li>
 * </ol>
 * </p>
 * @since 1.0
 */
@Documented
@Retention(RetentionPolicy.CLASS)
@Target({ METHOD, PARAMETER, LOCAL_VARIABLE })
public @interface NonNull {
	// marker annotation with no members
}
Commit	Line	Data
	1	/*******************************************************************************
	2	* Copyright (c) 2011, 2012 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.LOCAL_VARIABLE;
	15	import static java.lang.annotation.ElementType.METHOD;
	16	import static java.lang.annotation.ElementType.PARAMETER;
	17
	18	import java.lang.annotation.Documented;
	19	import java.lang.annotation.Retention;
	20	import java.lang.annotation.RetentionPolicy;
	21	import java.lang.annotation.Target;
	22
	23	/**
	24	* Qualifier for a type in a method signature or a local variable declaration:
	25	* The entity (return value, parameter, local variable) whose type has this
	26	* annotation can never have the value <code>null</code> at runtime.
	27	* <p>
	28	* This has two consequences:
	29	* <ol>
	30	* <li>Dereferencing the entity is safe, i.e., no <code>NullPointerException</code> can occur at runtime.</li>
	31	* <li>An attempt to bind a <code>null</code> value to the entity is a compile time error.</li>
	32	* </ol>
	33	* For the second case, diagnostics issued by the compiler should distinguish three situations:
	34	* <ol>
	35	* <li>Nullness of the value can be statically determined, the entity is definitely bound from either of:
	36	* <ul><li>the value <code>null</code>, or</li>
	37	* <li>an entity with a {@link Nullable @Nullable} type.</li></ul></li>
	38	* <li>Nullness cannot definitely be determined, because different code branches yield different results.</li>
	39	* <li>Nullness cannot be determined, because other program elements are involved for which
	40	* null annotations are lacking.</li>
	41	* </ol>
	42	* </p>
	43	* @since 1.0
	44	*/
	45	@Documented
	46	@Retention(RetentionPolicy.CLASS)
	47	@Target({ METHOD, PARAMETER, LOCAL_VARIABLE })
	48	public @interface NonNull {
	49	// marker annotation with no members
	50	}