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39 lines
2.3 KiB
Markdown
39 lines
2.3 KiB
Markdown
---
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title: File View Providers
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---
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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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A file view provider ([`FileViewProvider`](upsource:///platform/core-api/src/com/intellij/psi/FileViewProvider.java)) manages access to multiple PSI trees within a single file.
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For example, a JSPX page has a separate PSI tree for the Java code in it (`PsiJavaFile`), a separate tree for the XML code (`XmlFile`), and a separate tree for JSP as a whole ([`JspFile`](upsource:///java/jsp-openapi/src/com/intellij/psi/jsp/JspFile.java)).
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Each of the PSI trees covers the entire contents of the file, and contains special "outer language elements" in the places where contents in a different language can be found.
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A `FileViewProvider` instance corresponds to a single `VirtualFile`, a single `Document`, and can be used to retrieve multiple `PsiFile` instances.
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## How do I get a FileViewProvider?
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* From a `VirtualFile`: `PsiManager.getInstance(project).findViewProvider()`
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* From a `PsiFile`: `psiFile.getViewProvider()`
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## What can I do with a FileViewProvider?
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* To get the set of all languages for which PSI trees exist in a file: `fileViewProvider.getLanguages()`
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* To get the PSI tree for a particular language: `fileViewProvider.getPsi(language)`. For example, to get the PSI tree for XML, use `fileViewProvider.getPsi(XMLLanguage.INSTANCE)`.
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* To find an element of a particular language at the specified offset in the file: `fileViewProvider.findElementAt(offset, language)`
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## How do I extend the FileViewProvider?
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To create a file type that has multiple interspersing trees for different languages, a plugin must contain an extension to the `com.intellij.fileType.fileViewProviderFactory` extension point.
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Implement [`FileViewProviderFactory`](upsource:///platform/core-api/src/com/intellij/psi/FileViewProviderFactory.java) and return your `FileViewProvider` implementation from `createFileViewProvider()` method.
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Register as follows in `plugin.xml`:
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```xml
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<extensions defaultExtensionNs="com.intellij">
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<fileType.fileViewProviderFactory filetype="%file_type%" implementationClass="com.plugin.MyFileViewProviderFactory" />
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</extensions>
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```
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Where `%file_type%` refers to the type of the file being created (for example, "JFS"). |