Make HTTP response codes explicit for documentation

This requires a higher Java language level for the source,
while keeping Java 8 compatibility for the target.

build.gradle

@@ -137,8 +137,10 @@ configure(subprojects) {
 
     java {
         toolchain {
-            languageVersion = JavaLanguageVersion.of(8)
+            languageVersion = JavaLanguageVersion.of(11)
         }
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
         withSourcesJar()
     }
 

htmlSanityCheck-core/src/main/java/org/aim42/htmlsanitycheck/check/SuggestingChecker.java

@@ -27,8 +27,8 @@ public SuggestingChecker(Configuration pConfig) {
     /**
      * let the instance determine the list of possible values
      * Examples:
-     * - MissingImageFilesChecker -> collect the names of images files
-     * - BrokenCrossReferencesChecker -> collect all (internal) link targets
+     * - MissingImageFilesChecker → collect the names of images files
+     * - BrokenCrossReferencesChecker → collect all (internal) link targets
      **/
     protected abstract void setValidPossibilities();
 

htmlSanityCheck-core/src/main/java/org/aim42/htmlsanitycheck/html/HtmlPage.java

@@ -103,7 +103,7 @@ public final List<String> getAllMapNames() {
     }
 
     /**
-     * @return list of all usemap-references y with <img src="x" usemap="y"
+     * @return list of all usemap-references y with &lt;img src="x" usemap="y" ...
      */
     public List<String> getAllUsemapRefs() {
         return getImagesWithUsemapDeclaration().stream()
@@ -133,7 +133,7 @@ public final List<HtmlElement> getAllImageTagsWithNonEmptyAltAttribute() {
     }
 
     /**
-     * builds an immutable list of <img...> tags, where
+     * Builds an immutable list of &lt;img...&gt; tags, where
      * the alt-tag is missing or empty ("").
      */
     public final List<HtmlElement> getAllImageTagsWithMissingAltAttribute() {
@@ -169,11 +169,11 @@ public final List<HtmlElement> getAllIds() {
     }
 
     /**
-     * @return List < String >  of all href-attributes
+     * @return List<String> of all href-attributes
      * <p>
      * common pitfalls with hrefs:
      * - local hrefs start with # (like "#appendix")
-     * - remote hrefs should be valid URLs (like "<a href="https://google.com">https://google.com</a>")
+     * - remote hrefs should be valid URLs (like "&lt;a href="https://google.com"&gt;https://google.com&lt;/a&gt;")
      * - remote hrefs might start with other than http (e.g. https, mailto, telnet, ssh)
      * - hrefs might start with file://
      * - href might be empty string (nobody knows wtf this is good for, but html parsers usually accept it)
@@ -206,8 +206,15 @@ public List<HtmlElement> getImagesWithUsemapDeclaration() {
     }
 
     /**
-     * html-map has the following form:
-     * <map name="mapName"><area...><area...></map>
+     * An HTML map has the following form:
+     *
+     * <code>
+     *     &lt;map name="mapName"&gt;
+     *         &lt;area...&gt;
+     *         &lt;area...&gt;
+     *     &lt;/map&gt;
+     * </code>
+     *
      * <p>
      * collect all area elements for a given map.
      * If more than one map exists with this name, areas

htmlSanityCheck-core/src/main/java/org/aim42/htmlsanitycheck/report/SummarizerUtil.java

@@ -2,10 +2,10 @@
 
 public class SummarizerUtil {
     /**
-     * returns the percentage of successful checks.
+     * Returns the percentage of successful checks.
      * <p>
      * Edge case:
-     * 0 checks -> 100% successful
+     * 0 checks → 100% successful
      */
     public static int percentSuccessful(int totalChecks, int totalNrOfFindings) {
 

htmlSanityCheck-core/src/main/java/org/aim42/htmlsanitycheck/tools/Web.java

@@ -25,13 +25,45 @@ private Web() {
 
     // these are regarded as "Success" when checking
     // http(s) links
-    public static final Set<Integer> HTTP_SUCCESS_CODES = initHttpReturnCodes(200, 208, 226, 226);
+    public static final Set<Integer> HTTP_SUCCESS_CODES = Set.of(
+            // tag::HTTP_SUCCESS_CODES[]
+            200, 201, 202, 203, 204,
+            205, 206, 207, 208, 226
+            // end::HTTP_SUCCESS_CODES[]
+    );
+
+    public static final Set<Integer> HTTP_REDIRECT_CODES = Set.of(
+            // tag::HTTP_REDIRECT_CODES[]
+            300, 301, 302, 303, 304,
+            305, 306, 307, 308
+            // end::HTTP_REDIRECT_CODES[]
+    );
+
+    private static Set<Integer> join (Set<Integer> first, Set<Integer> second) {
+        Set<Integer> result = new HashSet<>(first);
+        result.addAll(second);
 
-    public static final Set<Integer> HTTP_WARNING_CODES = initHttpReturnCodes(100, 102, 300, 308);
-
-    public static final Set<Integer> HTTP_ERROR_CODES = initHttpReturnCodes(400, 451, 500, 511);
+        return Collections.unmodifiableSet(result);
+    }
 
-    public static final Set<Integer> HTTP_REDIRECT_CODES = initHttpReturnCodes(301, 303, 307, 308);
+    public static final Set<Integer> HTTP_WARNING_CODES = join (Set.of(
+            // tag::HTTP_WARNING_CODES[]
+            100, 101, 102
+            // end::HTTP_WARNING_CODES[]
+    ), HTTP_REDIRECT_CODES);
+
+    public static final Set<Integer> HTTP_ERROR_CODES = Set.of(
+            // tag::HTTP_ERROR_CODES[]
+            400, 401, 402, 403, 404,
+            405, 406, 407, 408, 409,
+            410, 411, 412, 413, 414,
+            415, 416, 417, 418, 421,
+            422, 423, 424, 425, 426,
+            428, 429, 431, 451,
+            500, 501, 502, 503, 504,
+            505, 506, 507, 508, 510, 511
+            // end::HTTP_ERROR_CODES[]
+    );
 
     public static final Set<String> POSSIBLE_EXTENSIONS = initExtensions();
 
@@ -45,12 +77,6 @@ private Web() {
 
     private static final Pattern linkPattern = Pattern.compile("^//.*$");
 
-    private static Set<Integer> initHttpReturnCodes(int aLow, int aHigh, int bLow, int bHigh) {
-        Set<Integer> result = IntStream.rangeClosed(aLow, aHigh).collect(HashSet::new, Set::add, Set::addAll);
-        result.addAll(IntStream.rangeClosed(bLow, bHigh).collect(HashSet::new, Set::add, Set::addAll));
-        return Collections.unmodifiableSet(result);
-    }
-
     private static Set<String> initExtensions() {
         Set<String> result = new HashSet<>(8);
         result.add("html");
@@ -79,6 +105,7 @@ public static boolean isInternetConnectionAvailable() {
     protected static boolean isInternetConnectionAvailable(String host) {
         try {
             // if we can get google's address, there is the Internet...
+            //noinspection ResultOfMethodCallIgnored
             InetAddress.getByName(host);
             return true;
         } catch (UnknownHostException e) {