Add a possibility to override compare doc info logic in CompareTool

DEVSIX-7045

Author: vitali.prudnikovich

kernel/src/main/java/com/itextpdf/kernel/utils/CompareTool.java

@@ -810,8 +810,8 @@ public String compareDocumentInfo(String outPdf, String cmpPdf, byte[] outPass,
                 PdfReader readerCmp = new PdfReader(cmpPdf, getCmpReaderProperties());
                 PdfDocument cmpDocument = new PdfDocument(readerCmp,
                         new DocumentProperties().setEventCountingMetaInfo(metaInfo))) {
-            String[] cmpInfo = convertInfo(cmpDocument.getDocumentInfo());
-            String[] outInfo = convertInfo(outDocument.getDocumentInfo());
+            String[] cmpInfo = convertDocInfoToStrings(cmpDocument.getDocumentInfo());
+            String[] outInfo = convertDocInfoToStrings(outDocument.getDocumentInfo());
             for (int i = 0; i < cmpInfo.length; ++i) {
                 if (!cmpInfo[i].equals(outInfo[i])) {
                     message = MessageFormatUtil.format("Document info fail. Expected: \"{0}\", actual: \"{1}\"", cmpInfo[i], outInfo[i]);
@@ -926,7 +926,16 @@ public String compareTagStructures(String outPdf, String cmpPdf) throws IOExcept
         return message;
     }
 
-    String[] convertInfo(PdfDocumentInfo info) {
+    /**
+     * Converts document info into a string array.
+     * <p>
+     * Converts document info into a string array. It can be used to compare PdfDocumentInfo later on.
+     * Default implementation retrieves title, author, subject, keywords and producer.
+     *
+     * @param info an instance of PdfDocumentInfo to be converted.
+     * @return String array with all the document info tester is interested in.
+     */
+    protected String[] convertDocInfoToStrings(PdfDocumentInfo info) {
         String[] convertedInfo = new String[]{"", "", "", "", ""};
         String infoValue = info.getTitle();
         if (infoValue != null)
@@ -1813,7 +1822,7 @@ private static class PngFileFilter implements FileFilter {
         private String currentOutPdfName;
 
         public PngFileFilter (String currentOutPdfName) {
-        this.currentOutPdfName = currentOutPdfName;
+            this.currentOutPdfName = currentOutPdfName;
         }
 
         public boolean accept(File pathname) {

kernel/src/test/java/com/itextpdf/kernel/utils/CompareToolTest.java

@@ -48,9 +48,12 @@ This file is part of the iText (R) project.
 import com.itextpdf.commons.utils.SystemUtil;
 import com.itextpdf.kernel.font.PdfFontFactory;
 import com.itextpdf.kernel.geom.Rectangle;
+import com.itextpdf.kernel.pdf.DocumentProperties;
 import com.itextpdf.kernel.pdf.PdfArray;
 import com.itextpdf.kernel.pdf.PdfDocument;
+import com.itextpdf.kernel.pdf.PdfDocumentInfo;
 import com.itextpdf.kernel.pdf.PdfPage;
+import com.itextpdf.kernel.pdf.PdfReader;
 import com.itextpdf.kernel.pdf.PdfWriter;
 import com.itextpdf.kernel.pdf.annot.PdfLinkAnnotation;
 import com.itextpdf.kernel.pdf.canvas.PdfCanvas;
@@ -286,4 +289,27 @@ public void compareFilesWithDiffLinkAnnotationTest() throws IOException {
 
         Assert.assertNotNull(new CompareTool().compareLinkAnnotations(firstPdf, secondPdf));
     }
+
+    @Test
+    public void convertDocInfoToStringsTest() throws IOException {
+        String inPdf = sourceFolder + "test.pdf";
+
+        class TestCompareTool extends CompareTool {
+            @Override
+            protected String[] convertDocInfoToStrings(PdfDocumentInfo info) {
+                return super.convertDocInfoToStrings(info);
+            }
+        }
+
+        CompareTool compareTool = new TestCompareTool();
+        try (PdfReader reader = new PdfReader(inPdf, compareTool.getOutReaderProperties());
+                PdfDocument doc = new PdfDocument(reader)) {
+            String[] docInfo = compareTool.convertDocInfoToStrings(doc.getDocumentInfo());
+            Assert.assertEquals("very long title to compare later on", docInfo[0]);
+            Assert.assertEquals("itext7core", docInfo[1]);
+            Assert.assertEquals("test file", docInfo[2]);
+            Assert.assertEquals("new job", docInfo[3]);
+            Assert.assertEquals("Adobe Acrobat Pro DC (64-bit) <version>", docInfo[4]);
+                }
+    }
 }