io.gdcc.xoai.dataprovider.handlers.helpers.MetadataHelper Maven / Gradle / Ivy

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OAI-PMH data provider implementation. Use it to build an OAI-PMH endpoint, providing your data records as harvestable resources.

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package io.gdcc.xoai.dataprovider.handlers.helpers;

import io.gdcc.xoai.dataprovider.exceptions.InternalOAIException;
import io.gdcc.xoai.dataprovider.model.Context;
import io.gdcc.xoai.dataprovider.model.MetadataFormat;
import io.gdcc.xoai.model.oaipmh.results.record.Metadata;
import io.gdcc.xoai.xml.EchoElement;
import io.gdcc.xoai.xml.XSLPipeline;
import io.gdcc.xoai.xml.XmlWriter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import javax.xml.stream.XMLStreamException;
import javax.xml.transform.TransformerException;

public class MetadataHelper {
    public static Metadata process(Metadata metadata, MetadataFormat format, Context context) {
        try (ByteArrayOutputStream outStream = new ByteArrayOutputStream();
                XmlWriter writer = new XmlWriter(outStream); ) {
            metadata.write(writer);
            writer.flush();

            XSLPipeline pipeline =
                    new XSLPipeline(new ByteArrayInputStream(outStream.toByteArray()), true);

            EchoElement element =
                    new EchoElement(
                            pipeline.apply(context.getTransformer())
                                    .apply(format.getTransformer())
                                    .process());

            /*
             * This is here for Dataverse 4/5 backward compatibility.
             * @deprecated Remove when Dataverse 6 is old enough that no ones uses this workaround anymore.
             */
            Metadata processed = new Metadata(element);
            // Copy attributes if present. This is here because of Dataverse 4/5 compatibility.
            metadata.getAttributes().ifPresent(a -> a.forEach(processed::withAttribute));

            return processed;
        } catch (XMLStreamException | TransformerException | IOException e) {
            throw new InternalOAIException(e);
        }
    }
}