nl.dedicon.pipeline.braille.calabash.impl.EmptyBackCoverStep Maven / Gradle / Ivy

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package nl.dedicon.pipeline.braille.calabash.impl;

import com.xmlcalabash.core.XProcException;
import com.xmlcalabash.core.XProcRuntime;
import com.xmlcalabash.core.XProcStep;
import com.xmlcalabash.io.ReadablePipe;
import com.xmlcalabash.io.WritablePipe;
import com.xmlcalabash.library.DefaultStep;
import com.xmlcalabash.runtime.XAtomicStep;
import java.io.InputStream;
import java.net.URL;
import net.sf.saxon.s9api.QName;
import net.sf.saxon.s9api.SaxonApiException;
import net.sf.saxon.s9api.XQueryCompiler;
import net.sf.saxon.s9api.XQueryEvaluator;
import net.sf.saxon.s9api.XQueryExecutable;
import net.sf.saxon.s9api.XdmNode;
import net.sf.saxon.s9api.XdmValue;
import nl.dedicon.pipeline.braille.step.Utils;
import org.daisy.common.xproc.calabash.XProcStepProvider;
import org.osgi.service.component.annotations.Component;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.Document;

/**
 * XProc step to make sure that the back cover of a volume has no braille
 * 
 * @author Paul Rambags
 */
public class EmptyBackCoverStep extends DefaultStep {

    private static final Logger logger = LoggerFactory.getLogger(EmptyBackCoverStep.class);

    private static final QName _xquery = new QName("xquery");

    private ReadablePipe source = null;
    private WritablePipe result = null;
    
    private EmptyBackCoverStep(XProcRuntime runtime, XAtomicStep step) {
        super(runtime, step);
    }

    @Override
    public void setInput(String port, ReadablePipe pipe) {
        source = pipe;
    }

    @Override
    public void setOutput(String port, WritablePipe pipe) {
        result = pipe;
    }

    @Override
    public void reset() {
        source.resetReader();
        result.resetWriter();
    }

    @Override
    public void run() throws SaxonApiException {
        
        super.run();

        try {

            XdmNode pef = source.read();

            String xquery = getOption(_xquery, "");

            // convert the immutable XdmNode to a modifiable Document
            Document document = Utils.convertToDocument(pef);

            InputStream query = new URL(xquery).openConnection().getInputStream();
            
            XQueryCompiler xqCompiler = runtime.getProcessor().newXQueryCompiler();
            XQueryExecutable xqExecutable = xqCompiler.compile(query);
            XQueryEvaluator xqEvaluator = xqExecutable.load();

            xqEvaluator.setSource(pef.asSource());
            XdmValue xqResult = xqEvaluator.evaluate();

            // get the first node from the result
            XdmNode newPef = null;
            for (XdmValue xqValue : xqResult) {
                if (xqValue instanceof XdmNode) {
                    newPef = (XdmNode)xqValue;
                    break;
                }
            };

            result.write(newPef);
            
        } catch (Exception e) {

            logger.error("dedicon:empty-back-cover failed", e);
            throw new XProcException(step.getNode(), e);

        }
    }

    @Component(
            name = "dedicon:empty-back-cover",
            service = {XProcStepProvider.class},
            property = {"type:String={http://www.dedicon.nl}empty-back-cover"}
    )
    public static class Provider implements XProcStepProvider {

        @Override
        public XProcStep newStep(XProcRuntime runtime, XAtomicStep step) {
            return new EmptyBackCoverStep(runtime, step);
        }

    }
}