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* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.pdfbox.preflight.utils;
import org.apache.pdfbox.pdmodel.PDResources;
import org.apache.pdfbox.preflight.PreflightConfiguration;
import static org.apache.pdfbox.preflight.PreflightConstants.ERROR_PDF_PROCESSING_MISSING;
import static org.apache.pdfbox.preflight.PreflightConstants.ERROR_PDF_PROCESSING;
import org.apache.pdfbox.preflight.PreflightContext;
import org.apache.pdfbox.preflight.PreflightPath;
import org.apache.pdfbox.preflight.exception.ValidationException;
import org.apache.pdfbox.preflight.process.ValidationProcess;
import org.apache.pdfbox.preflight.ValidationResult.ValidationError;
public final class ContextHelper
{
private ContextHelper()
{
}
/**
* Check that the element parameter isn't null before calling the
* {@link #callValidation(PreflightContext, Object, String)} method.
*
* @param context
* @param element
* @param processName
* @throws ValidationException
*/
public static void validateElement(PreflightContext context, Object element, String processName) throws ValidationException
{
if (element == null)
{
context.addValidationError(new ValidationError(ERROR_PDF_PROCESSING_MISSING, "Unable to process an element if it is null."));
}
else
{
callValidation(context, element, processName);
}
}
/**
* Put the element to check on the top of the ValidationPath and call the validation method on the Process.
*
* @param context
* (mandatory) the preflight context that contains all required information
* @param element
* @param processName
* the process to instantiate and to compute
* @throws ValidationException
*/
private static void callValidation(PreflightContext context, Object element, String processName)
throws ValidationException
{
PreflightPath validationPath = context.getValidationPath();
if (hasRecursion(context, element, validationPath))
{
return;
}
boolean needPop = validationPath.pushObject(element);
PreflightConfiguration config = context.getConfig();
ValidationProcess process = config.getInstanceOfProcess(processName);
process.validate(context);
if (needPop)
{
validationPath.pop();
}
}
// detect recursion that would lead to stack overflow
private static boolean hasRecursion(PreflightContext context, Object element, PreflightPath validationPath)
{
if (element instanceof PDResources)
{
for (int i = 0; i < validationPath.size(); ++i)
{
Object obj = validationPath.getPathElement(i, Object.class);
if (obj instanceof PDResources)
{
PDResources pdRes = (PDResources) obj;
if (pdRes.getCOSObject() == ((PDResources) element).getCOSObject())
{
context.addValidationError(new ValidationError(ERROR_PDF_PROCESSING, "Resources recursion"));
return true;
}
}
}
}
return false;
}
/**
* call directly the {@link #callValidation(PreflightContext, Object, String)}
*
* @param context
* @param processName
* @throws ValidationException
*/
public static void validateElement(PreflightContext context, String processName) throws ValidationException
{
callValidation(context, null, processName);
}
}