Vladimir Petrenko 63947c2c46
code_intentions.md: edit considering Intentions Actions Preview feature (#1417)
purpose:
- make it clearer that "before/after examples" and "intention action preview" are different things.
- simplify navigation to "Intention Action Preview" topic
2025-01-27 14:42:41 +01:00

106 lines
6.1 KiB
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<!-- Copyright 2000-2024 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license. -->
# Intentions
<link-summary>Intention actions allow fixing code issues or transforming the code to a different form.</link-summary>
<tldr>
**Product Help:** [Intention Actions](https://www.jetbrains.com/help/idea/intention-actions.html)
**UI Guidelines:** [](inspections.md)
</tldr>
This topic describes the [conditional_operator_intention](%gh-sdk-samples-master%/conditional_operator_intention), a sample plugin that adds a new [intention action](https://www.jetbrains.com/help/idea/intention-actions.html) to the IDE Intentions list.
In addition, the sample plugin contains a JUnit-based test.
## About Intention Actions
The IntelliJ Platform analyzes your code and helps handle situations that may result in errors.
When a possible problem is suspected, the IDE suggests an appropriate intention action, denoted with special icons.
See the [Inspections](inspections.md) topic in UI Guidelines on naming, writing description, and message texts for inspections/intentions.
You can view a list of all available intention actions as well as enable/disable them using the [Intentions List](https://www.jetbrains.com/help/idea/intention-actions.html#intention-settings) in <ui-path>Settings | Editor | Intentions</ui-path>.
See the [Intention Action Preview](code_intentions_preview.md) topic on providing a preview of changes that can be made by executing an intention.
## Techniques Used
The [conditional_operator_intention](%gh-sdk-samples-master%/conditional_operator_intention) sample plugin illustrates the use of the following techniques:
- How to analyze a [PSI tree](psi_files.md).
- How to find a Java token of interest in the PSI tree.
- How to invoke a quick-fix action for a token element under the cursor using the [`PsiElementBaseIntentionAction`](%gh-ic%/platform/lang-api/src/com/intellij/codeInsight/intention/PsiElementBaseIntentionAction.java) class.
- How to create a JUnit test for this plugin using the [`IdeaTestFixtureFactory`](%gh-ic%/platform/testFramework/src/com/intellij/testFramework/fixtures/IdeaTestFixtureFactory.java) class.
- How to add an intention description and before/after examples in the Settings dialog
> In the case of providing multiple intention actions for a single element, their ordering is indeterministic due to performance reasons.
> It is possible to push specific items up or down by implementing
> [`HighPriorityAction`](%gh-ic%/platform/analysis-api/src/com/intellij/codeInsight/intention/HighPriorityAction.java)
> or
> [`LowPriorityAction`](%gh-ic%/platform/analysis-api/src/com/intellij/codeInsight/intention/LowPriorityAction.java)
> respectively.
>
{style="note"}
## Sample Plugin
When launched, the sample plugin adds the <control>SDK: Convert ternary operator to if statement</control> item to the <control>SDK intentions</control> group in the <ui-path>Settings | Editor | Intentions</ui-path>.
#### Running the Plugin
See [Code Samples](code_samples.md) on how to set up and run the plugin.
#### How does it work?
The plugin analyzes symbols under the cursor in your code opened in the editor.
If the cursor is positioned on the `?` conditional operator, IntelliJ IDEA proposes to replace this conditional (ternary) operator with the "if-then-else" statement:
![Convert ternary operator intention popup](ternary_operator_intention.png)
{width=675}
Invoking <control>SDK: Convert ternary operator to if statement</control> intention action will result in transforming expression to the form visible in the [preview](code_intentions_preview.md) popup (code fragment on the right).
#### Intention Description and examples
The intention description is available in the UI in two places:
- under <ui-path>Settings | Editor | Intentions | SDK Intentions | SDK: Convert ternary operator to if statement</ui-path>.
- near the selected intention action in the [Context Actions](https://www.jetbrains.com/help/idea/intention-actions.html#apply-intention-actions) popup
in the editor when [Preview](code_intentions_preview.md) cannot be shown.
The before/after examples are available in the UI
under <ui-path>Settings | Editor | Intentions | SDK Intentions | SDK: Convert ternary operator to if statement</ui-path>.
The plugin provides description and before/after examples files in the <path>resources/intentionDescriptions/ConditionalOperatorConverter</path> directory:
- <path>description.html</path> - provides the general information about the intention
- <path>after.java.template</path> - shows the code fragment that intention can change
- <path>before.java.template</path> - shows the code fragment after applying the intention
By default, the intention description directory name is the same as the intention class name.
It can be customized with the `<descriptionDirectoryName>` element in `<intentionAction>` in <path>plugin.xml</path>.
> If your intention class names are obfuscated in the [plugin distribution](plugin_content.md), always declare the `<descriptionDirectoryName>` element.
>
{style="warning"}
"Before" and "after" filenames pattern is <path>before.\$LANG_FILE_EXTENSION\$.template</path> and <path>after.\$LANG_FILE_EXTENSION\$.template</path> respectively.
If before/after preview is not needed, specify `<skipBeforeAfter>true</skipBeforeAfter>` in the `<intentionAction>` in <path>plugin.xml</path>.
> If a plugin project is multi-module, and it combines resources into a single JAR, make sure that all intention description files have unique names or paths.
> Otherwise, only the last packed description file will exist in the distribution package.
>
{style="warning"}
> See the [](providing_translations.md#bundled-translations) section for information about how to provide intention description translations in plugins.
#### Testing the Plugin
> Note that running the test requires setting system property `idea.home.path` in the `test` task configuration of the Gradle build script.
>
{style="note"}
The sample plugin contains the `ConditionalOperatorConverterTest` Java class and the test data in the <path>test/testData/</path> directory.
To perform the plugin test, run the `ConditionalOperatorConverterTest.testIntention()` method.