Add verapdf usage example

Author: MaximPlusov

verapdf-examples/src/main/java/IOTest4.java

@@ -0,0 +1,47 @@
+import org.verapdf.core.EncryptedPdfException;
+import org.verapdf.core.ModelParsingException;
+import org.verapdf.core.ValidationException;
+import org.verapdf.gf.foundry.VeraGreenfieldFoundryProvider;
+import org.verapdf.pdfa.Foundries;
+import org.verapdf.pdfa.PDFAParser;
+import org.verapdf.pdfa.PDFAValidator;
+import org.verapdf.pdfa.flavours.PDFAFlavour;
+import org.verapdf.pdfa.flavours.PDFFlavours;
+import org.verapdf.pdfa.results.ValidationResult;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+//	example from https://docs.verapdf.org/develop/processor/ (veraPDF.github.io\develop\processor\index.md)
+public class IOTest4 {
+
+	public static void main(String[] args) {
+		VeraGreenfieldFoundryProvider.initialise();
+		try (PDFAParser parser = Foundries.defaultInstance().createParser(new FileInputStream("test.pdf"))) {
+			List<PDFAFlavour> detectedFlavours = parser.getFlavours();
+			List<PDFAFlavour> flavours = new LinkedList<>();
+			for (PDFAFlavour flavour : detectedFlavours) {
+				// iterate through all detected flavours and pick up PDF/A and PDF/UA ones for validation
+				if (PDFFlavours.isFlavourFamily(flavour, PDFAFlavour.SpecificationFamily.PDF_A) ||
+						PDFFlavours.isFlavourFamily(flavour, PDFAFlavour.SpecificationFamily.PDF_UA)) {
+					flavours.add(flavour);
+				}
+			}
+			PDFAValidator validator = Foundries.defaultInstance().createValidator(Collections.emptyList());
+			List<ValidationResult> results = validator.validateAll(parser);
+			for (ValidationResult result : results) {
+				if (result.isCompliant()) {
+					// File complies to flavour
+				} else {
+					// File doesn't comply to flavour
+				}
+			}
+		} catch (IOException | ValidationException | ModelParsingException | EncryptedPdfException exception) {
+			// Exception during validation
+		}
+	}
+
+}