[//]: # (title: 19. Quick Fix)

<!-- Copyright 2000-2022 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file. -->

<include src="language_and_filetype.md" include-id="custom_language_tutorial_header"></include>

A quick fix for a custom language supports the IntelliJ Platform-based IDE feature [Intention Actions](https://www.jetbrains.com/help/idea/intention-actions.html#apply-intention-actions).
For the Simple Language, this tutorial adds a quick fix that helps to define an unresolved property from its usage.

**Reference**: [](code_inspections_and_intentions.md)

## Update the Element Factory
The `SimpleElementFactory` is updated to include two new methods to support the user choice of creating a new property for the Simple Language quick fix.
The new `createCRLF()` method supports adding a newline to the end of the [`test.simple`](lexer_and_parser_definition.md#run-the-project) file before adding a new property.
A new overload of `createProperty()` creates a new `key`-`value` pair for Simple Language.

```java
```
{src="simple_language_plugin/src/main/java/org/intellij/sdk/language/psi/SimpleElementFactory.java"}

## Define an Intention Action
The `SimpleCreatePropertyQuickFix` creates a property in the file chosen by the user - in this case, a Java file containing a `prefix:key` - and navigate to this property after creation.
Under the hood, `SimpleCreatePropertyQuickFix` is an Intention Action.
For a more in-depth example of an Intention Action, see [`conditional_operator_intention`](%gh-sdk-samples%/conditional_operator_intention).

```java
```
{src="simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleCreatePropertyQuickFix.java"}

## Update the Annotator
When a `badProperty` annotation is created, the `badProperty.registerFix()` method is called.
This method call registers the `SimpleCreatePropertyQuickFix` as the Intention Action for the Intellij Platform to use to correct the problem.

```java
```
{src="simple_language_plugin/src/main/java/org/intellij/sdk/language/SimpleAnnotator.java"}

## Run the Project
Run the project by using the Gradle [`runIde`](gradle_prerequisites.md#running-a-simple-gradle-based-intellij-platform-plugin) task.
Open the test [Java file](annotator.md#run-the-project).

To test `SimpleCreatePropertyQuickFix`, change `simple:website` to `simple:website.url`.
The key `website.url` is highlighted by `SimpleAnnotator` as an invalid key, as shown below.
Choose "Create Property".

![Quick Fix](quick_fix.png){width="800"}

The IDE opens the <path>test.simple</path> file and adds `website.url` as a new key.
Add the new value `jetbrains.com` for the new `website.url` key.

![New Property](new_property.png)

Now switch back to the Java file; the new key is highlighted as valid.