[mmootygam]

I'm using the AST to create new java code in a sort of extended JavaCompletionProposal. I'm wondering what is the easiest way to create single and multi line comments in an existing compilationunit? I would hope to preserve the undo stack.

[Gaurav Saxena]

if u have object of AST then u might already have object of ICompilationUnit...

u can directly call the method codeComplete(....) for ur purpose...

ICompilationUnit myCU;

myCU.codeComplete(....) ;
hope u understand..

[mmootygam]

Thanks for your help, but I've solved this myself since I posted the thread. I used the following code:

// Actually edits the document via the AST, using ASTRewrite.
		ASTRewrite rewriter = ASTRewrite.create(ast);
		ASTHandler handler = new ASTHandler();
		ASTNode currentNode = handler.descend(root,
				CalciteCompletionProposalComputer
						.getIdentifierBeforeOffset(context));
		ASTNode parent = currentNode.getParent();
		//ITrackedNodePosition parentLocation = rewriter.track(currentNode.getParent());
		ListRewrite lrw;
		try {
			if (parent instanceof Block)
				lrw = rewriter
						.getListRewrite(parent, Block.STATEMENTS_PROPERTY);
			else
				lrw = rewriter.getListRewrite(parent,
						((AbstractTypeDeclaration) parent)
								.getBodyDeclarationsProperty());
		} catch (Throwable e) {
			return;
		}
		for (ASTNode prior : preStatements) {
			lrw.insertBefore(prior, currentNode, null);
		}
		lrw = rewriter.getListRewrite(root, CompilationUnit.IMPORTS_PROPERTY);
		for (ImportDeclaration imp : importStatements)
			lrw.insertLast(imp, null);
		TextEdit edits = rewriter.rewriteAST(document, null);

		// Sets cursor position and applies the primary edit
		int cursorDelta = super.getReplacementString().indexOf(',');
		if (cursorDelta == -1)
			cursorDelta = regexParseDisplay(super.getReplacementString());
		if (preStatements.size() > 0)
			cursorDelta += COMMENT_LENGTH;
		cursorDelta += getMultiEditLength(edits);
		super.setCursorPosition(cursorDelta);
		super.apply(document, trigger, offset);

		try {
			// Preserves the undo stack.
			edits.apply(document);
		} catch (MalformedTreeException e) {
			e.printStackTrace();
		} catch (BadLocationException e) {
			e.printStackTrace();
		}

If anyone who reads this needs more help, please just reply to this thread.

[Gaurav Saxena]

I would like to know ur way...

[mmootygam]

Sorry, I misread this thread when I first replied. I edited it to answer the right question, and decided I'd go ahead and include my code anyway. The bolded lines are the ones most important to preserving the undo stack. The other ones are just there for context.