| <html> |
| <head> |
| <title>Quick Assist with APT</title> |
| </head> |
| |
| <body> |
| <h1>Creating a Quick-Fix processor for APT</h2> |
| <h2>Instructions for creating an Eclipse Quick Fix Processor</h3> |
| |
| <p> |
| It is possible to write quick-fix processors to fix errors that your APT processor |
| detects. To do that, you must do two things: |
| |
| <ol> |
| <li>Print errors indicating that they are fixable</li> |
| <li>Write an APT quick fix processor and register it with APT</li> |
| </ol> |
| </p> |
| |
| <h3>1. Print errors indicating that they are fixable</h3> |
| |
| When running inside Eclipse, you may downcast the Messager object that you get from |
| the AnnotationProcessorEnvironment's <code>getMessager()</code> method. Inside Eclipse, |
| that object will also be an <code>org.eclipse.jdt.apt.core.util.EclipseMessager</code>, which |
| declares some additional methods over the standard Messager, like the following: |
| |
| <code> |
| <ul> |
| <li>printFixableError(SourcePosition pos, String msg, String pluginId, String errorId)</li> |
| <li>printFixableError(String msg, String pluginId, String errorId)</li> |
| </ul> |
| </code> |
| |
| The pluginId should be the ID of the plugin within which you will be creating your |
| quick fix processor. The errorId should be a String that will make sense in the context of |
| your quick fix processor, say, "requiredAnnotationValueMissing", or whatever will provide |
| the necessary information to provide your quick fix. |
| |
| <p> |
| |
| <h3>2. Create an APT Quick Fix Processor</h3> |
| |
| Begin by creating a class that implements <code>org.eclipse.jdt.apt.ui.quickfix.IAPTQuickFixProvider</code>, |
| which has only one method: |
| |
| <code> |
| <ul> |
| <li>public IJavaCompletionProposal [] getProposals(IInvocationContext context, |
| IProblemLocation [] locations) throws CoreException; |
| </ul> |
| </code> |
| |
| You'll notice this is very similar to the standard Eclipse quick fix processor API, |
| but you will only get called for problems that you created.</p> |
| |
| Once you've created your quick fix processor implementation, you can register it with an extension |
| point on the APT UI plugin, aptQuickFixProvider. Here is an example of what to put in your |
| plugin's plugin.xml: |
| |
| <pre> |
| <extension |
| point="org.eclipse.jdt.apt.ui.aptQuickFixProvider"> |
| <quickFixProvider |
| className="com.foo.MyAptQuickFixProvider" |
| errorCode="com.foo.AptErrors" |
| pluginId="com.foo.Apt"/> |
| </extension> |
| </pre> |
| |
| That's it! Once your plugin is running inside Eclipse, your APT Quick Fix Provider |
| will get called each time the user attempts to quick-fix one of the errors |
| your processor created. |
