Insert String into Editor from within a ToolWindow

Into which editor? Also, what exactly did you try and what doesn't work? In general, an editor doesn't care whether the code that's inserting text into it was invoked from a toolwindow or from some other part of the UI.

You may find this document useful: http://confluence.jetbrains.com/display/IDEADEV/IntelliJ+IDEA+Architectural+Overview

Hi Dmitry,

yeah I have read  http://confluence.jetbrains.com/display/IDEADEV/IntelliJ+IDEA+Architectural+Overview. But I am quite new to Swing and GUI development and I perhaps understand 50% of the documentation.

I want to insert the String into the current Editor at the current cursor position.

The only code that nearly works and I still have is the following:

FileEditorManager manager = FileEditorManager.getInstance(project);
final Editor editor = manager.getSelectedTextEditor();
assert editor != null;
final int cursorOffset = editor.getCaretModel().getOffset();
final Document document = editor.getDocument();

ApplicationManager.getApplication().runWriteAction(new Runnable() {
     @Override
     public void run() {
          document.insertString(cursorOffset, snippetCode);
     }
});

But if this code is executed I get the follwing error:

 [  17297]  ERROR - llij.ide.plugins.PluginManager - Must not change document outside command or undo-transparent action. See com.intellij.openapi.command.WriteCommandAction or com.intellij.openapi.command.CommandProcessor 
com.intellij.util.IncorrectOperationException: Must not change document outside command or undo-transparent action. See com.intellij.openapi.command.WriteCommandAction or com.intellij.openapi.command.CommandProcessor
...

Please try reading the error message produced by this operation and following the instructions contained in it.

I got it now:

FileEditorManager manager = FileEditorManager.getInstance(project);
final Editor editor = manager.getSelectedTextEditor();
assert editor != null;
final int cursorOffset = editor.getCaretModel().getOffset();
final Document document = editor.getDocument();

new WriteCommandAction(project){
     @Override
     protected void run(@NotNull Result result) throws Throwable {
          document.insertString(cursorOffset, snippetCode);
     }
}.execute();