public static LinkedHashMap extractPlaceholdersWithPositions()

in taverna-rest-activity/src/main/java/org/apache/taverna/activities/rest/URISignatureHandler.java [79:141]
46 lines of code
11 McCabe index (conditional complexity)

	public static LinkedHashMap<String, Integer> extractPlaceholdersWithPositions(
			String uriSignature) {
		// no signature - nothing to process
		if (uriSignature == null || uriSignature.isEmpty())
			throw new URISignatureParsingException(
					"URI signature is null or empty - nothing to process.");

		LinkedHashMap<String, Integer> foundPlaceholdersWithPositions = new LinkedHashMap<>();

		int nestingLevel = 0;
		int startSymbolIdx = -1;

		// go through the signature character by character trying to extract
		// placeholders
		for (int i = 0; i < uriSignature.length(); i++) {
			switch (uriSignature.charAt(i)) {
			case PLACEHOLDER_START_SYMBOL:
				if (++nestingLevel != 1)
					throw new URISignatureParsingException(
							"Malformed URL: at least two parameter placeholder opening\n" +
									"symbols follow each other without being closed appropriately\n" +
							"(possibly the signature contains nested placeholders).");
				startSymbolIdx = i;
				break;

			case PLACEHOLDER_END_SYMBOL:
				if (--nestingLevel < 0)
					throw new URISignatureParsingException(
							"Malformed URL: parameter placeholder closing symbol found before the opening one.");
				if (nestingLevel == 0) {
					// correctly opened and closed placeholder found; check if
					// it is a "fresh" one
					String placeholderCandidate = uriSignature.substring(
							startSymbolIdx + 1, i);
					if (!foundPlaceholdersWithPositions
							.containsKey(placeholderCandidate)) {
						foundPlaceholdersWithPositions.put(
								placeholderCandidate, startSymbolIdx + 1);
					} else {
						throw new URISignatureParsingException(
								"Malformed URL: duplicate parameter placeholder \""
										+ placeholderCandidate + "\" found.");
					}
				}
				break;

			default:
				continue;
			}
		}

		// the final check - make sure that after traversing the string, we are
		// not "inside" one of the placeholders (e.g. this could happen if a
		// placeholder
		// opening symbol was found, but the closing one never occurred after
		// that)
		if (nestingLevel > 0)
			throw new URISignatureParsingException(
					"Malformed URL: parameter placeholder opening symbol found,\n"
							+ "but the closing one has not been encountered.");

		return foundPlaceholdersWithPositions;
	}