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79 lines
4.2 KiB
Markdown
[//]: # (title: Code Intentions)
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<!-- Copyright 2000-2020 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. -->
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This topic describes the [conditional_operator_intention](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/conditional_operator_intention), a sample plugin that adds a new [intention action](https://www.jetbrains.com/help/idea/intention-actions.html) to the IntelliJ Platform Intentions list.
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In addition, the sample plugin contains a JUnit-based test.
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## About Intention Actions
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The **IntelliJ Platform** analyzes your code and helps handle situations that may result in errors.
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When a possible problem is suspected, the IDE suggests an appropriate intention action, denoted with special icons.
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For more information, refer to [Intention Actions](https://www.jetbrains.com/help/idea/intention-actions.html) in the **IntelliJ IDEA** Web Help.
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You can view a list of all available intention actions using the [Intention List](https://www.jetbrains.com/help/idea/intention-actions.html#intention-settings) provided by the IDE.
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**To display Intention List**
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1. Open the **Settings** dialog box.
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2. Under **IDE Settings**, click **Intentions**. This displays the list of all intention actions currently available in **IntelliJ IDEA**.
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- The intention actions are grouped according to the areas of their use.
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- To enable/disable an intention action, select/deselect the check box to its left.
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## Techniques Used
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The [conditional_operator_intention](https://github.com/JetBrains/intellij-sdk-code-samples/tree/main/conditional_operator_intention) sample plugin illustrates the use of the following techniques:
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- How to analyze a [PSI tree](psi_files.md).
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- How to find a Java token of interest in the PSI tree.
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- How to invoke a quick fix action for a token element under cursor using the [`PsiElementBaseIntentionAction`](upsource:///platform/lang-api/src/com/intellij/codeInsight/intention/PsiElementBaseIntentionAction.java) class.
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- How to create a JUnit test for this plugin using the [`IdeaTestFixtureFactory`](upsource:///platform/testFramework/src/com/intellij/testFramework/fixtures/IdeaTestFixtureFactory.java) class.
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## Sample Plugin
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The **ConditionalOperatorConverter** sample plugin is available in the `<%IntelliJ SDK Docs project%>/code_samples/conditional_operator_intention` directory.
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When launched, this plugin adds the **Convert ternary operator if statement** item to the **Conditional Operator** node in the IDEA Intentions list:
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#### Running the Plugin
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**To run the sample plugin**
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1. Start **IntelliJ IDEA** and open the **conditionalOperatorConvertor** plugin project saved into the `<%IntelliJ SDK Docs project%>/code_samples/conditional_operator_intention` directory.
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2. Open the [Project Structure](https://www.jetbrains.com/help/idea/project-structure-dialog.html) dialog and ensure that the project settings are valid for your environment.
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3. If necessary, modify the [Run/Debug Configurations](https://www.jetbrains.com/idea/webhelp/run-debug-configuration-plugin.html) and Run the plugin by choosing the **Run** on the main menu.
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#### How does it work?
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The plugin analyzes symbols under the cursor in your code opened in the IDEA editor.
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If the cursor is positioned on the "?" conditional operator, **IntelliJ IDEA** proposes to replace this conditional (ternary) operator with the "if-then-else" statement:
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In this example, the code:
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```java
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return (n>=0) ? n : -n;
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```
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will be replaced with the code:
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```java
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if ((n>=0)) {
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return n;
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} else {
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return -n;
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}
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```
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##### Testing the Plugin
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> Please note that running the test requires setting system property `idea.home.path` in `test {}` block of `build.gradle`
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>
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{type="note"}
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The sample plugin contains the `ConditionalOperatorConverterTest` Java class and the test data in the `test/testData/` directory.
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To perform the plugin test, run the `ConditionalOperatorConverterTest.testIntention()` method.
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For detailed information about testing and all related procedures, refer to [Testing](https://www.jetbrains.com/help/idea/performing-tests.html) in the **IntelliJ IDEA** Web Help.
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