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57 lines
2.8 KiB
Markdown
57 lines
2.8 KiB
Markdown
---
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title: Plugin Extension Points
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---
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> **NOTE** See [Plugin Extensions](plugin_extensions.md) for _using_ extension points in your plugin.
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By defining _extension points_ in your plugin, you can allow other plugins to extend the functionality of your plugin.
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There are two types of extension points:
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* _Interface_ extension points allow other plugins to extend your plugins with _code_. When you define an interface
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extension point, you specify an interface, and other plugins will provide classes implementing that interface.
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You'll then be able to invoke methods on those interfaces.
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* _Bean_ extension points allow other plugins to extend your plugins with _data_. You specify the fully qualified
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name of an extension class, and other plugins will provide data which will be turned into instances of that class.
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## How to declare extension points
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You can declare extensions and extension points in the plugin configuration file `plugin.xml`, within the `<extensions>` and `<extensionPoints>` sections, respectively.
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To declare extension points in your plugin, add an `<extensionPoints>` section to your `plugin.xml`. Then insert a child element `<extensionPoint>` that defines the extension point name and the name of a bean class or an interface that is allowed to extend the plugin functionality in the `name`, `beanClass` and `interface` attributes, respectively.
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```xml
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<extensionPoints>
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<extensionPoint name="myExtensionPoint1" beanClass="com.myplugin.MyBeanClass">
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<extensionPoint name="myExtensionPoint2" interface="com.myplugin.MyInterface">
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</extensionPoints>
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```
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* The `beanClass` attribute sets a bean class that specifies one or several properties annotated with the [`@Attribute`](upsource:///platform/util/src/com/intellij/util/xmlb/annotations/Attribute.java) annotation.
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* The `interface` attribute sets an interface the plugin that contributes to the extension point must implement.
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The plugin that contributes to the extension point will read those properties from the `plugin.xml` file.
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To clarify this, consider the following sample `MyBeanClass` bean class used in the above `plugin.xml` file:
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```java
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public class MyBeanClass extends AbstractExtensionPointBean {
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@Attribute("key")
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public String key;
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@Attribute("implementationClass")
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public String implementationClass;
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public String getKey() {
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return key;
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}
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public String getClass() {
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return implementationClass;
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}
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}
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```
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To declare an extension designed to access the `myExtensionPoint1` extension point, your `plugin.xml` file must contain the `<myExtensionPoint1>` tag with the `key` and `implementationClass` attributes set to appropriate values.
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> **TIP** See [Extension properties code insight](plugin_extensions.md#extension-properties-code-insight) on how to provide smart completion/validation.
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