| /******************************************************************************* |
| * Copyright (c) 2009 IBM Corporation 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: |
| * IBM Corporation - initial API and implementation |
| *******************************************************************************/ |
| package org.eclipse.e4.core.di.annotations; |
| |
| import static java.lang.annotation.RetentionPolicy.RUNTIME; |
| |
| import java.lang.annotation.Documented; |
| import java.lang.annotation.ElementType; |
| import java.lang.annotation.Retention; |
| import java.lang.annotation.Target; |
| |
| /** |
| * This annotation can be applied to methods, fields, and parameters to |
| * mark them as optional for the dependency injection. Typically, if the injector is |
| * unable to find a value to inject, then injection will fail. However, if this annotation |
| * is specified, then: |
| * <ul> |
| * <li> for parameters: a <code>null</code> value will be injected; </li> |
| * <li> for methods: the method calls will be skipped; </li> |
| * <li> for fields: the values will not be injected. </li> |
| * </ul> |
| * <p>Example usage: |
| * <pre> |
| * public class Car { |
| * @Inject @Optional void setOverdrive(OverdriveMode mode); |
| * ... |
| * } |
| * </pre> |
| * </p> |
| */ |
| @Documented |
| @Target( { ElementType.METHOD, ElementType.FIELD, ElementType.PARAMETER }) |
| @Retention(RUNTIME) |
| public @interface Optional { |
| } |
