MSDN.java

// Part of the MSDN blog link repairer code

	private static final Pattern MSDN_BLOG_ARTICLE_URL = getBrokenURLPattern(
			"blogs\\.msdn\\.com/(b/)?(.*)/archive/\\d+/\\d+/\\d+/(.*)\\.aspx"),
			MSDN_BLOG_TAG_URL = getBrokenURLPattern("blogs\\.msdn\\.com/(b/)?([^\\s/]*)/archive/tags/(\\w+)"),
			MSDN_BLOG_HOME_URL = getBrokenURLPattern("blogs\\.msdn\\.com/(b/)?([^\\s/]*)/(?!\\w)"),

  /**
	 * Checks the current url for known broken URL patterns; if a substitution can be made, it will be checked for
	 * availability and replaced.
	 * 
	 * @return whether the URL is broken or not
	 */
	private boolean checkForKnownBrokenURL() throws Exception {
    // ...
    
		// MSDN blogs
		for (Pattern pattern : new Pattern[] { MSDN_BLOG_ARTICLE_URL, MSDN_BLOG_TAG_URL, MSDN_BLOG_HOME_URL }) {
			Matcher matcher = pattern.matcher(url);
			if (!matcher.find())
				continue;
			if (Utility.isAvailable(url))
				continue;

			// Blog name
			String blogName = matcher.group(4);
			if ("vcblog".equals(blogName)) {
				blogName = "cppblog";
			}

			// Possible base URLs
			String[] replacements = new String[] { "devblogs.microsoft.com/" + blogName + "/",
					"docs.microsoft.com/en-us/archive/blogs/" + blogName + "/" };
			if ("chuckw".equals(blogName)) {
				replacements = new String[] { "walbourn.github.io/" };
			}

			// Determine possible new URLs to check
			List<String> newURLs = new ArrayList<>();
			if (pattern != MSDN_BLOG_HOME_URL) {
				String[] components = matcher.group(5).split("-");
				// The algorithm below is rather brute force and not effective if there are hundreds of possibilities.
				if (components.length < 8) {
					// The article at
					// http://blogs.msdn.com/b/rwlodarc/archive/2007/07/18/using-wpf-s-inplacebitmapmetadatawriter.aspx
					// is now hosted at
					// https://docs.microsoft.com/en-us/archive/blogs/rwlodarc/using-wpfs-inplacebitmapmetadatawriter
					// because the word "WPF's" is now treated differently in the URL.
					for (int i = (1 << components.length - 1) - 1; i >= 0; i--) {
						for (String replacement : replacements) {
							StringBuilder part = new StringBuilder(components[0]);
							for (int j = 0; j < components.length - 1; j++) {
								if ((i & (1 << j)) != 0) {
									part.append("-");
								}
								part.append(components[j + 1]);
							}
							newURLs.add(matcher.replaceFirst("$1//" + replacement
									+ (pattern == MSDN_BLOG_TAG_URL ? "tag/" : "") + part.toString()));
						}
					}
				}
			}
			if (newURLs.isEmpty()) {
				// Default replacement strategy
				for (String replacement : replacements) {
					newURLs.add(
							matcher.replaceFirst("$1//" + replacement + (pattern != MSDN_BLOG_HOME_URL ? "$5" : "")));
				}
			}

			// Check possible new URLs
			String newURL = Utility.checkURLs(newURLs);
			if (newURL != null) {
				url = newURL;
				return true;
			}
		}