Refactor interfaces in com.itextpdf.kernel.pdf.tagutils package

Replaced IAccessibleElement+AccessibilityProperties with AccessibilityProperties abstract class;
Old AccessibilityProperties class is replaced with DefaultAccessibilityProperties implementation of abstract class;
Changed most of the API that concerns tag roles in order to make it work with java strings;
Introduced separate StandardRoles class for possible role constants;
Introduced PdfStructureAttributes wrapper for structure attributes.

DEVSIX-1236

Author: yulian-gaponenko

forms/src/main/java/com/itextpdf/forms/PdfAcroForm.java

@@ -52,7 +52,6 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.PdfBoolean;
 import com.itextpdf.kernel.pdf.PdfDictionary;
 import com.itextpdf.kernel.pdf.PdfDocument;
-import com.itextpdf.kernel.pdf.PdfIndirectReference;
 import com.itextpdf.kernel.pdf.PdfName;
 import com.itextpdf.kernel.pdf.PdfNumber;
 import com.itextpdf.kernel.pdf.PdfObject;
@@ -64,6 +63,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.VersionConforming;
 import com.itextpdf.kernel.pdf.annot.PdfAnnotation;
 import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
+import com.itextpdf.kernel.pdf.tagging.StandardRoles;
 import com.itextpdf.kernel.pdf.tagutils.TagReference;
 import com.itextpdf.kernel.pdf.tagutils.TagTreePointer;
 import com.itextpdf.kernel.pdf.xobject.PdfFormXObject;
@@ -957,7 +957,7 @@ private void addWidgetAnnotationToPage(PdfPage page, PdfAnnotation annot) {
         if (tagged) {
             tagPointer = page.getDocument().getTagStructureContext().getAutoTaggingPointer();
             //TODO attributes?
-            tagPointer.addTag(PdfName.Form);
+            tagPointer.addTag(StandardRoles.FORM);
         }
 
         page.addAnnotation(annot);

forms/src/test/java/com/itextpdf/forms/FormFieldsTaggingTest.java

@@ -46,9 +46,9 @@ This file is part of the iText (R) project.
 import com.itextpdf.forms.fields.PdfFormField;
 import com.itextpdf.kernel.geom.Rectangle;
 import com.itextpdf.kernel.pdf.PdfDocument;
-import com.itextpdf.kernel.pdf.PdfName;
 import com.itextpdf.kernel.pdf.PdfReader;
 import com.itextpdf.kernel.pdf.PdfWriter;
+import com.itextpdf.kernel.pdf.tagging.StandardRoles;
 import com.itextpdf.kernel.pdf.tagutils.TagTreePointer;
 import com.itextpdf.kernel.utils.CompareTool;
 import com.itextpdf.test.ExtendedITextTest;
@@ -219,7 +219,7 @@ public void formFieldTaggingTest07() throws IOException, InterruptedException, P
         PdfButtonFormField pushButton = PdfFormField.createPushButton(pdfDoc, new Rectangle(36, 650, 40, 20), "push", "Capcha");
 
         TagTreePointer tagPointer = pdfDoc.getTagStructureContext().getAutoTaggingPointer();
-        tagPointer.moveToKid(PdfName.Div);
+        tagPointer.moveToKid(StandardRoles.DIV);
         acroForm.addField(pushButton);
 
         pdfDoc.close();

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfName.java

@@ -550,6 +550,7 @@ public class PdfName extends PdfPrimitiveObject implements Comparable<PdfName> {
     public static final PdfName Note = createDirectName("Note");
     public static final PdfName NotForPublicRelease = createDirectName("NotForPublicRelease");
     public static final PdfName NS = createDirectName("NS");
+    public static final PdfName NSO = createDirectName("NSO");
     public static final PdfName NumCopies = createDirectName("NumCopies");
     public static final PdfName Nums = createDirectName("Nums");
     public static final PdfName O = createDirectName("O");

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfOutline.java

@@ -51,7 +51,6 @@ This file is part of the iText (R) project.
 import java.io.Serializable;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
 
 /**
  * Document outline object
@@ -212,7 +211,7 @@ public void addDestination(PdfDestination destination) {
     public void addAction(PdfAction action) {
         content.put(PdfName.A, action.getPdfObject());
     }
-    
+
     /**
      * Defines if the outline needs to be closed or not.
      * By default, outlines are open.

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfPage.java

@@ -54,6 +54,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.annot.PdfLinkAnnotation;
 import com.itextpdf.kernel.pdf.filespec.PdfFileSpec;
 import com.itextpdf.kernel.pdf.tagging.PdfStructTreeRoot;
+import com.itextpdf.kernel.pdf.tagging.StandardRoles;
 import com.itextpdf.kernel.pdf.tagutils.TagTreePointer;
 import com.itextpdf.kernel.pdf.xobject.PdfFormXObject;
 import com.itextpdf.kernel.pdf.xobject.PdfImageXObject;
@@ -452,8 +453,8 @@ public PdfDocument getDocument() {
      * If the page belongs to the document which is tagged, page flushing also triggers flushing of the tags,
      * which are considered to belong to the page. The logic that defines if the given tag (structure element) belongs
      * to the page is the following: if all the marked content references (dictionary or number references), that are the
-     * descenders of the given structure element, belong to the current page - the tag is considered
-     * to belong to the page. If tag has descenders from several pages - it is flushed, if all other pages except the
+     * descendants of the given structure element, belong to the current page - the tag is considered
+     * to belong to the page. If tag has descendants from several pages - it is flushed, if all other pages except the
      * current one are flushed.
      */
     @Override
@@ -854,8 +855,8 @@ public PdfPage removeAnnotation(PdfAnnotation annotation) {
         if (getDocument().isTagged()) {
             TagTreePointer tagPointer = getDocument().getTagStructureContext().removeAnnotationTag(annotation);
             if (tagPointer != null) {
-                boolean standardAnnotTagRole = tagPointer.getRole().equals(PdfName.Annot)
-                        || tagPointer.getRole().equals(PdfName.Form);
+                boolean standardAnnotTagRole = tagPointer.getRole().equals(StandardRoles.ANNOT)
+                        || tagPointer.getRole().equals(StandardRoles.FORM);
                 if (tagPointer.getKidsRoles().size() == 0 && standardAnnotTagRole) {
                     tagPointer.removeTag();
                 }

kernel/src/main/java/com/itextpdf/kernel/pdf/PdfResources.java

@@ -43,7 +43,6 @@ This file is part of the iText (R) project.
  */
 package com.itextpdf.kernel.pdf;
 
-import com.itextpdf.kernel.PdfException;
 import com.itextpdf.kernel.font.PdfFont;
 import com.itextpdf.kernel.pdf.colorspace.PdfColorSpace;
 import com.itextpdf.kernel.pdf.colorspace.PdfPattern;
@@ -66,7 +65,7 @@ This file is part of the iText (R) project.
 public class PdfResources extends PdfObjectWrapper<PdfDictionary> {
 
     private static final long serialVersionUID = 7160318458835945391L;
-	
+
     private static final String F = "F";
     private static final String Im = "Im";
     private static final String Fm = "Fm";

kernel/src/main/java/com/itextpdf/kernel/pdf/annot/PdfAnnotation.java

@@ -52,7 +52,6 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.geom.Rectangle;
 import com.itextpdf.kernel.pdf.PdfAnnotationBorder;
 import com.itextpdf.kernel.pdf.PdfArray;
-import com.itextpdf.kernel.pdf.PdfBoolean;
 import com.itextpdf.kernel.pdf.PdfDictionary;
 import com.itextpdf.kernel.pdf.PdfDocument;
 import com.itextpdf.kernel.pdf.PdfIndirectReference;
@@ -62,7 +61,6 @@ This file is part of the iText (R) project.
 import com.itextpdf.kernel.pdf.PdfObjectWrapper;
 import com.itextpdf.kernel.pdf.PdfPage;
 import com.itextpdf.kernel.pdf.PdfString;
-import com.itextpdf.kernel.pdf.action.PdfAction;
 import com.itextpdf.kernel.pdf.filespec.PdfFileSpec;
 import com.itextpdf.kernel.pdf.layer.IPdfOCG;
 import org.slf4j.Logger;

kernel/src/main/java/com/itextpdf/kernel/pdf/annot/PdfLinkAnnotation.java

@@ -59,7 +59,7 @@ public class PdfLinkAnnotation extends PdfAnnotation {
     private static final long serialVersionUID = 5795613340575331536L;
 
     private static final Logger logger = LoggerFactory.getLogger(PdfLinkAnnotation.class);
-	
+
     /**
      * Highlight modes.
      */

kernel/src/main/java/com/itextpdf/kernel/pdf/annot/PdfMarkupAnnotation.java

@@ -44,18 +44,12 @@ This file is part of the iText (R) project.
 package com.itextpdf.kernel.pdf.annot;
 
 import com.itextpdf.io.LogMessageConstant;
-import com.itextpdf.kernel.colors.Color;
-import com.itextpdf.kernel.colors.DeviceCmyk;
-import com.itextpdf.kernel.colors.DeviceGray;
-import com.itextpdf.kernel.colors.DeviceRgb;
 import com.itextpdf.kernel.geom.Rectangle;
-import com.itextpdf.kernel.pdf.PdfArray;
 import com.itextpdf.kernel.pdf.PdfDictionary;
 import com.itextpdf.kernel.pdf.PdfName;
 import com.itextpdf.kernel.pdf.PdfNumber;
 import com.itextpdf.kernel.pdf.PdfObject;
 import com.itextpdf.kernel.pdf.PdfString;
-import com.itextpdf.kernel.pdf.tagging.PdfMcrDictionary;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 

kernel/src/main/java/com/itextpdf/kernel/pdf/canvas/CanvasTag.java

@@ -200,7 +200,7 @@ public PdfDictionary getProperties() {
     public String getActualText() {
         return getPropertyAsString(PdfName.ActualText);
     }
-    
+
     public String getExpansionText() {
         return getPropertyAsString(PdfName.E);
     }
@@ -213,7 +213,7 @@ private String getPropertyAsString(PdfName name) {
         }
         return result;
     }
-    
+
     private void ensurePropertiesInit() {
         if (properties == null) {
             properties = new PdfDictionary();