additional edits + comments

Author: hopehadfield

org.eclipse.jdt.ls.core/src/org/eclipse/jdt/ls/core/internal/handlers/CodeActionResolveHandler.java

@@ -24,7 +24,6 @@
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.jdt.core.IBuffer;
 import org.eclipse.jdt.core.ICompilationUnit;
-import org.eclipse.jdt.core.IJavaElement;
 import org.eclipse.jdt.core.manipulation.ChangeCorrectionProposalCore;
 import org.eclipse.jdt.internal.corext.fix.LinkedProposalModelCore;
 import org.eclipse.jdt.internal.corext.fix.LinkedProposalPositionGroupCore;
@@ -84,18 +83,31 @@ public CodeAction resolve(CodeAction params, IProgressMonitor monitor) {
 		return params;
 	}
 
+	/***
+	 * Supports linked correction proposals by converting them to snippets.
+	 * Represents a
+	 * {@link org.eclipse.jdt.internal.corext.fix.LinkedProposalPositionGroupCore}
+	 * with snippet choice syntax if the group has multiple proposals, otherwise
+	 * represents it as a placeholder.
+	 *
+	 * @param proposal
+	 *            the proposal to add support for
+	 * @param edit
+	 *            the current edit to be returned with the code action
+	 * @throws CoreException
+	 */
 	private static final void addSnippetsIfApplicable(LinkedCorrectionProposalCore proposal, WorkspaceEdit edit) throws CoreException {
-		Object modifiedElement = proposal.getChange().getModifiedElement();
-		ICompilationUnit compilationUnit = (ICompilationUnit) ((IJavaElement) modifiedElement).getAncestor(IJavaElement.COMPILATION_UNIT);
+		ICompilationUnit compilationUnit = proposal.getCompilationUnit();
 		IBuffer buffer = compilationUnit.getBuffer();
 		LinkedProposalModelCore linkedProposals = proposal.getLinkedProposalModel();
 		List<Triple> snippets = new ArrayList<>();
 		Iterator<LinkedProposalPositionGroupCore> it = linkedProposals.getPositionGroupCoreIterator();
-		int snippetNumber = 1;
+
 		while (it.hasNext()) {
 			LinkedProposalPositionGroupCore group = it.next();
 			ProposalCore[] proposalList = group.getProposals();
 			PositionInformation[] positionList = group.getPositions();
+			// Sorts in ascending order to ensure first position in list has the smallest offset
 			Arrays.sort(positionList, new Comparator<PositionInformation>() {
 				@Override
 				public int compare(PositionInformation p1, PositionInformation p2) {
@@ -104,12 +116,16 @@ public int compare(PositionInformation p1, PositionInformation p2) {
 			});
 			StringBuilder snippet = new StringBuilder();
 			snippet.append(SNIPPET_CHOICE_INDICATOR);
+
 			for (int i = 0; i < positionList.length; i++) {
 				int offset = positionList[i].getOffset();
 				int length = positionList[i].getLength();
+
 				// Create snippet on first iteration
 				if (i == 0) {
 					LinkedPosition linkedPosition = new LinkedPosition(JsonRpcHelpers.toDocument(buffer), positionList[i].getOffset(), positionList[i].getLength(), positionList[i].getSequenceRank());
+
+					// Groups with no proposals will have the snippet text added while amending the WorkspaceEdit
 					for (int j = 0; j < proposalList.length; j++) {
 						org.eclipse.text.edits.TextEdit editWithText = findReplaceOrInsertEdit(proposalList[j].computeEdits(0, linkedPosition, '\u0000', 0, new LinkedModeModel()));
 						if (editWithText != null) {
@@ -119,39 +135,42 @@ public int compare(PositionInformation p1, PositionInformation p2) {
 							snippet.append(((ReplaceEdit) editWithText).getText());
 						}
 					}
-					//					// If snippet is empty, ignore this group
-					//					if (snippet.toString().equals(String.valueOf(SNIPPET_CHOICE_INDICATOR))) {
-					//						break;
-					//					}
+
 					snippet.append(SNIPPET_CHOICE_POSTFIX);
 					// If snippet only has one choice, remove choice indicators
 					if (snippet.indexOf(SNIPPET_CHOICE_DELIMITER) == -1) {
 						snippet.setCharAt(0, ':');
 						snippet.deleteCharAt(snippet.length() - 2);
 					}
+					// Snippet is added with smallest offset as 0th element
 					snippets.add(new Triple(snippet.toString(), offset, length));
 				} else {
+					// Add offset/length values from additional positions in group to previously created snippet
 					Triple currentSnippet = snippets.get(snippets.size() - 1);
 					currentSnippet.offset.add(offset);
 					currentSnippet.length.add(length);
 				}
 			}
 		}
 		if (!snippets.isEmpty()) {
-			// Sort snippets in descending order based on offset, so that the edits are applied in an order that does not alter the offset of later edits
+			// Sort snippets based on offset of earliest occurrence to enable correct numbering
 			snippets.sort(null);
-			// ListIterator<Triple> li = snippets.listIterator(snippets.size());
+			int snippetNumber = 1;
 			for (int i = snippets.size() - 1; i >= 0; i--) {
 				Triple element = snippets.get(i);
 				element.snippet = SNIPPET_PREFIX + snippetNumber + element.snippet;
 				snippetNumber++;
+				// Separate snippets with multiple positions into individual instances in list
 				for (int j = 1; j < element.offset.size(); j++) {
 					snippets.add(new Triple(element.snippet.toString(), element.offset.get(j), element.length.get(j)));
 					element.offset.remove(j);
 					element.length.remove(j);
 				}
 			}
+			// Re-sort snippets (with the added individual instances) by offset in descending order,
+			// so that the amendments to the text edit are applied in an order that does not alter the offset of later amendments
 			snippets.sort(null);
+
 			for (int i = 0; i < edit.getDocumentChanges().size(); i++) {
 				if (edit.getDocumentChanges().get(i).isLeft()) {
 					List<TextEdit> edits = edit.getDocumentChanges().get(i).getLeft().getEdits();
@@ -160,20 +179,22 @@ public int compare(PositionInformation p1, PositionInformation p2) {
 						StringBuilder replacementText = new StringBuilder(edits.get(j).getNewText());
 						int rangeStart = JsonRpcHelpers.toOffset(buffer, editRange.getStart().getLine(), editRange.getStart().getCharacter());
 						int rangeEnd = rangeStart + replacementText.length();
+
 						for (int k = 0; k < snippets.size(); k++) {
-							Triple snippetHolder = snippets.get(k);
-							if (snippetHolder.offset.get(0) >= rangeStart && snippetHolder.offset.get(0) <= rangeEnd) {
-								int replaceStart = snippetHolder.offset.get(0) - rangeStart;
-								int replaceEnd = replaceStart + snippetHolder.length.get(0);
-								if (snippetHolder.snippet.endsWith(":}")) {
-									snippetHolder.snippet = snippetHolder.snippet.replaceFirst(":", ":" + replacementText.substring(replaceStart, replaceEnd));
+							Triple currentSnippet = snippets.get(k);
+							if (currentSnippet.offset.get(0) >= rangeStart && currentSnippet.offset.get(0) <= rangeEnd) {
+								int replaceStart = currentSnippet.offset.get(0) - rangeStart;
+								int replaceEnd = replaceStart + currentSnippet.length.get(0);
+								// If snippet text has not been added due to no elements in the proposal list, create snippet based on the text in the given position range
+								if (currentSnippet.snippet.endsWith(":}")) {
+									currentSnippet.snippet = currentSnippet.snippet.replaceFirst(":", ":" + replacementText.substring(replaceStart, replaceEnd));
 								}
-								replacementText.replace(replaceStart, replaceEnd, snippetHolder.snippet);
+								replacementText.replace(replaceStart, replaceEnd, currentSnippet.snippet);
 							}
 						}
+
 						SnippetTextEdit newEdit = new SnippetTextEdit(editRange, replacementText.toString());
-						edits.remove(j);
-						edits.add(j, newEdit);
+						edits.set(j, newEdit);
 					}
 				}
 			}
@@ -208,6 +229,7 @@ private static final class Triple implements Comparable<Triple> {
 			this.length.add(length);
 		}
 
+		// Sorts in descending order based on 0th (smallest) element of offset list
 		@Override
 		public int compareTo(Triple other) {
 			return other.offset.get(0) - this.offset.get(0);