Documents
A Document is an editable sequence of Unicode characters, typically corresponding to the text contents of a virtual file.
Line breaks in a document are always normalized to \n. The IntelliJ Platform handles encoding and line break conversions when loading and saving documents transparently.
How do I get a Document?
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What can I do with a Document?
You may perform any operations that access or modify the file contents on the "plain text" level (as a sequence of characters, not as a tree of Program Structure Interface (PSI) elements).
Where does a Document come from?
Document instances are created when some operation needs to access the text contents of a file (in particular, this is necessary to build the PSI for a file). Also, document instances not linked to any Virtual Files can be created temporarily, for example, representing the contents of a text editor field in a dialog.
How long does a Document persist?
Document instances are weakly referenced from VirtualFile instances. Thus, an unmodified Document instance can be garbage-collected if no one references it, and a new instance is created if the document contents are reaccessed later.
How do I create a Document?
For creating a new file on disk, please do not create a Document but a PSI file and get its Document (see How do I create a PSI file?). To create a Document instance that isn't bound to anything, use EditorFactory.createDocument().
How do I get notified when documents change?
Document.addDocumentListener()allows receiving notifications about changes in a particularDocumentinstance.EditorFactory.getEventMulticaster().addDocumentListener()allows receiving notifications about changes in all open documents.Register
FileDocumentManagerListenerlistener or subscribe toAppTopics.FILE_DOCUMENT_SYNCon any level bus to receive notifications when aDocumentis saved or reloaded from disk.
What are the rules of working with documents?
The general read/write action rules are in effect (see Threading Model). Besides, any operations which modify the contents of the document must be wrapped in a command (CommandProcessor.executeCommand()). executeCommand() calls can be nested, and the outermost executeCommand() call is added to the undo stack. If multiple documents are modified within a command, undoing this command will, by default, show a confirmation dialog to the user.
If the file corresponding to a Document is read-only (for example, not checked out from the version control system), document modifications will fail. Thus, before modifying the Document, it is necessary to call ReadonlyStatusHandler.ensureFilesWritable() to check out the file.
All text strings passed to Document modification methods (setText(), insertString(), replaceString()) must use only \n as line separators.
See also Working with Text in Editors Basics tutorial.
Are there any utilities available for working with documents?
DocumentUtil contains utility methods for Document processing. This allows you to get information like the text offsets of particular lines. This is particularly useful when you need text location/offset information about a given PsiElement.