org.apache.pdfbox.preflight.metadata.RDFAboutAttributeConcordanceValidation Maven / Gradle / Ivy
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package org.apache.pdfbox.preflight.metadata;
import java.util.List;
import org.apache.pdfbox.preflight.exception.ValidationException;
import org.apache.xmpbox.XMPMetadata;
import org.apache.xmpbox.schema.XMPSchema;
/**
* Class which checks that all elements within an rdf:RDF have the same value for their rdf:about
* attributes.
*
* @author Germain Costenobel
*
*/
public class RDFAboutAttributeConcordanceValidation
{
/**
*
* @param metadata the XMP metadata.
* @throws DifferentRDFAboutException
* @throws ValidationException
*/
public void validateRDFAboutAttributes(XMPMetadata metadata) throws ValidationException, DifferentRDFAboutException
{
List schemas = metadata.getAllSchemas();
if (schemas.isEmpty())
{
throw new ValidationException("No schema found in the given metadata representation");
}
String about = schemas.get(0).getAboutValue();
// rdf:description must have an rdf:about attribute
for (XMPSchema xmpSchema : schemas)
{
// each rdf:Description must have the same rdf:about (or an empty one)
String schemaAboutValue = xmpSchema.getAboutValue();
if (!("".equals(schemaAboutValue) || "".equals(about) || about.equals(schemaAboutValue)))
{
throw new DifferentRDFAboutException();
}
if ("".equals(about))
{
about = schemaAboutValue;
}
}
}
public static class DifferentRDFAboutException extends Exception
{
private static final long serialVersionUID = 1L;
public DifferentRDFAboutException()
{
super("all rdf:about in RDF:rdf must have the same value");
}
}
}