update + restructure pom and add missing javadoc

src/main/java/net/sourceforge/plantuml/servlet/DiagramResponse.java

@@ -48,41 +48,69 @@ import net.sourceforge.plantuml.version.Version;
 import net.sourceforge.plantuml.error.PSystemError;
 import net.sourceforge.plantuml.ErrorUml;
 
-
 /**
  * Delegates the diagram generation from the UML source and the filling of the HTTP response with the diagram in the
  * right format. Its own responsibility is to produce the right HTTP headers.
  */
 public class DiagramResponse {
 
+    /**
+     * {@link FileFormat} to http content type mapping.
+     */
+    private static final Map<FileFormat, String> CONTENT_TYPE;
+    /**
+     * X-Powered-By http header value included in every response by default.
+     */
     private static final String POWERED_BY = "PlantUML Version " + Version.versionString();
 
-    private HttpServletResponse response;
-    private FileFormat format;
-    private HttpServletRequest request;
-    private static final Map<FileFormat, String> CONTENT_TYPE;
-    static {
-        Map<FileFormat, String> map = new HashMap<FileFormat, String>();
-        map.put(FileFormat.PNG, "image/png");
-        map.put(FileFormat.SVG, "image/svg+xml");
-        map.put(FileFormat.EPS, "application/postscript");
-        map.put(FileFormat.UTXT, "text/plain;charset=UTF-8");
-        map.put(FileFormat.BASE64, "text/plain; charset=x-user-defined");
-        CONTENT_TYPE = Collections.unmodifiableMap(map);
-    }
     static {
         OptionFlags.ALLOW_INCLUDE = false;
         if ("true".equalsIgnoreCase(System.getenv("ALLOW_PLANTUML_INCLUDE"))) {
             OptionFlags.ALLOW_INCLUDE = true;
         }
+        CONTENT_TYPE = Collections.unmodifiableMap(new HashMap<FileFormat, String>() {{
+            put(FileFormat.PNG, "image/png");
+            put(FileFormat.SVG, "image/svg+xml");
+            put(FileFormat.EPS, "application/postscript");
+            put(FileFormat.UTXT, "text/plain;charset=UTF-8");
+            put(FileFormat.BASE64, "text/plain; charset=x-user-defined");
+        }});
     }
 
-    public DiagramResponse(HttpServletResponse r, FileFormat f, HttpServletRequest rq) {
-        response = r;
-        format = f;
-        request = rq;
+    /**
+     * Response format.
+     */
+    private FileFormat format;
+    /**
+     * Http request.
+     */
+    private HttpServletRequest request;
+    /**
+     * Http response.
+     */
+    private HttpServletResponse response;
+
+    /**
+     * Create new diagram response instance.
+     *
+     * @param res http response
+     * @param fmt target file format
+     * @param req http request
+     */
+    public DiagramResponse(HttpServletResponse res, FileFormat fmt, HttpServletRequest req) {
+        response = res;
+        format = fmt;
+        request = req;
     }
 
+    /**
+     * Render and send a specific uml diagram.
+     *
+     * @param uml textual UML diagram(s) source
+     * @param idx diagram index of {@code uml} to send
+     *
+     * @throws IOException if an input or output exception occurred
+     */
     public void sendDiagram(String uml, int idx) throws IOException {
         response.addHeader("Access-Control-Allow-Origin", "*");
         response.setContentType(getContentType());
@@ -114,6 +142,13 @@ public class DiagramResponse {
         diagram.exportDiagram(response.getOutputStream(), idx, new FileFormatOption(format));
     }
 
+    /**
+     * Is block uml unmodified?
+     *
+     * @param blockUml block uml
+     *
+     * @return true if unmodified; otherwise false
+     */
     private boolean notModified(BlockUml blockUml) {
         final String ifNoneMatch = request.getHeader("If-None-Match");
         final long ifModifiedSince = request.getDateHeader("If-Modified-Since");
@@ -127,7 +162,13 @@ public class DiagramResponse {
         return ifNoneMatch.contains(etag);
     }
 
-
+    /**
+     * Produce and send the image map of the uml diagram in HTML format.
+     *
+     * @param uml textual UML diagram source
+     *
+     * @throws IOException if an input or output exception occurred
+     */
     public void sendMap(String uml) throws IOException {
         response.setContentType(getContentType());
         SourceStringReader reader = new SourceStringReader(uml);
@@ -145,15 +186,29 @@ public class DiagramResponse {
         }
     }
 
+    /**
+     * Check the syntax of the diagram and send a report in TEXT format.
+     *
+     * @param uml textual UML diagram source
+     *
+     * @throws IOException if an input or output exception occurred
+     */
     public void sendCheck(String uml) throws IOException {
         response.setContentType(getContentType());
         SourceStringReader reader = new SourceStringReader(uml);
         DiagramDescription desc = reader.outputImage(
-            new NullOutputStream(), new FileFormatOption(FileFormat.PNG, false));
+            new NullOutputStream(),
+            new FileFormatOption(FileFormat.PNG, false)
+        );
         PrintWriter httpOut = response.getWriter();
         httpOut.print(desc.getDescription());
     }
 
+    /**
+     * Add default header including cache headers to response.
+     *
+     * @param blockUml response block uml
+     */
     private void addHeaderForCache(BlockUml blockUml) {
         long today = System.currentTimeMillis();
         // Add http headers to force the browser to cache the image
@@ -177,12 +232,22 @@ public class DiagramResponse {
         addHeaders(response);
     }
 
+    /**
+     * Add default headers to response.
+     *
+     * @param response http response
+     */
     public static void addHeaders(HttpServletResponse response) {
         response.addHeader("X-Powered-By", POWERED_BY);
         response.addHeader("X-Patreon", "Support us on https://plantuml.com/patreon");
         response.addHeader("X-Donate", "https://plantuml.com/paypal");
     }
 
+    /**
+     * Get response content type.
+     *
+     * @return response content type
+     */
     private String getContentType() {
         return CONTENT_TYPE.get(format);
     }