com.itextpdf.pdfua.checkers.utils.headings.HeadingsChecker Maven / Gradle / Ivy
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/*
This file is part of the iText (R) project.
Copyright (c) 1998-2024 Apryse Group NV
Authors: Apryse Software.
This program is offered under a commercial and under the AGPL license.
For commercial licensing, contact us at https://itextpdf.com/sales. For AGPL licensing, see below.
AGPL licensing:
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Affero General Public License for more details.
You should have received a copy of the GNU Affero General Public License
along with this program. If not, see hRendererParents = new HashSet<>();
private final Set hPdfDictParents = new HashSet<>();
private int previousHn = -1;
private boolean wasAtLeastOneH = false;
/**
* Creates a new instance of {@link HeadingsChecker}.
*
* @param context The validation context.
*/
public HeadingsChecker(PdfUAValidationContext context) {
this.context = context;
}
/**
* Checks if layout element has correct heading.
*
* @param rendererObj layout element to check
*
* @throws PdfUAConformanceException if headings sequence is incorrect
*/
public void checkLayoutElement(Object rendererObj) {
IRenderer renderer = (IRenderer) rendererObj;
IPropertyContainer element = renderer.getModelElement();
if (element instanceof IAccessibleElement) {
IAccessibleElement accessibleElement = (IAccessibleElement) element;
String role = context.resolveToStandardRole(accessibleElement.getAccessibilityProperties().getRole());
checkHnSequence(role);
if (StandardRoles.H.equals(role)) {
IRenderer parent = renderer.getParent();
if (hRendererParents.contains(parent)) {
// Matterhorn-protocol checkpoint 14-006
throw new PdfUAConformanceException(PdfUAExceptionMessageConstants.MORE_THAN_ONE_H_TAG);
} else if (parent != null) {
hRendererParents.add(parent);
}
}
checkHAndHnUsing(role);
}
}
/**
* Checks if structure element has correct heading.
*
* @param structNode structure element to check
*
* @throws PdfUAConformanceException if headings sequence is incorrect
*/
public void checkStructElement(IStructureNode structNode) {
final String role = context.resolveToStandardRole(structNode);
if (role == null) {
return;
}
checkHnSequence(role);
if (StandardRoles.H.equals(role)) {
PdfDictionary parent = extractPdfDictFromNode(structNode.getParent());
if (hPdfDictParents.contains(parent)) {
// Matterhorn-protocol checkpoint 14-006
throw new PdfUAConformanceException(PdfUAExceptionMessageConstants.MORE_THAN_ONE_H_TAG);
} else if (parent != null) {
hPdfDictParents.add(parent);
}
}
checkHAndHnUsing(role);
}
private void checkHnSequence(String role) {
int currHn = extractNumber(role);
if (currHn != -1) {
if (previousHn == -1) {
if (currHn != 1) {
// Matterhorn-protocol checkpoint 14-002
throw new PdfUAConformanceException(PdfUAExceptionMessageConstants.H1_IS_SKIPPED);
}
} else if (currHn - previousHn > 1) {
// Matterhorn-protocol checkpoint 14-003
throw new PdfUAConformanceException(MessageFormatUtil.format(
PdfUAExceptionMessageConstants.HN_IS_SKIPPED, previousHn + 1));
}
previousHn = currHn;
}
}
private void checkHAndHnUsing(String role) {
if (StandardRoles.H.equals(role)) {
wasAtLeastOneH = true;
}
if (wasAtLeastOneH && previousHn != -1) {
// Matterhorn-protocol checkpoint 14-007
throw new PdfUAConformanceException(PdfUAExceptionMessageConstants.DOCUMENT_USES_BOTH_H_AND_HN);
}
}
private static int extractNumber(String heading) {
if (heading == null) {
return -1;
}
final Matcher matcher = Hn_PATTERN.matcher(heading);
if (matcher.matches()) {
return Integer.parseInt(matcher.group(1));
}
return -1;
}
private static PdfDictionary extractPdfDictFromNode(IStructureNode node) {
if (node instanceof PdfStructTreeRoot) {
return ((PdfStructTreeRoot) node).getPdfObject();
} else if (node instanceof PdfStructElem) {
return ((PdfStructElem) node).getPdfObject();
}
return null;
}
/**
* Handler class that checks heading tags while traversing the tag tree.
*/
public static class HeadingHandler extends ContextAwareTagTreeIteratorHandler {
private final HeadingsChecker checker;
/**
* Creates a new instance of {@link HeadingsChecker}.
*
* @param context The validation context.
*/
public HeadingHandler(PdfUAValidationContext context) {
super(context);
checker = new HeadingsChecker(context);
}
/**
* {@inheritDoc}
*/
@Override
public void nextElement(IStructureNode elem) {
checker.checkStructElement(elem);
}
}
}