fr.gael.dhus.datastore.processing.impl.ProcessProductIdentifier.java Source code

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Here is the source code for fr.gael.dhus.datastore.processing.impl.ProcessProductIdentifier.java

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/*
 * Data Hub Service (DHuS) - For Space data distribution.
 * Copyright (C) 2013,2014,2015 GAEL Systems
 *
 * This file is part of DHuS software sources.
 *
 * 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 <http://www.gnu.org/licenses/>.
 */
package fr.gael.dhus.datastore.processing.impl;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Collection;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.stereotype.Component;

import fr.gael.dhus.database.object.Product;
import fr.gael.dhus.datastore.processing.ProcessingProduct;
import fr.gael.drb.DrbNode;
import fr.gael.drb.DrbSequence;
import fr.gael.drb.query.Query;
import fr.gael.drbx.cortex.DrbCortexItemClass;
import fr.gael.drbx.cortex.DrbCortexModel;

/**
 * Extracts the product identifier and setup product field.
 */
@Component
public class ProcessProductIdentifier implements ProcessingProduct {
    private static Log logger = LogFactory.getLog(ProcessProductIdentifier.class);

    final public static String METADATA_NAMESPACE = "http://www.gael.fr/dhus#";
    final public static String PROPERTY = "identifier";

    @Override
    public String getDescription() {
        return "Processes Product Identifier";
    }

    @Override
    public String getLabel() {
        return "Product identifier";
    }

    private String process(URL url) {
        Collection<String> properties = null;
        DrbNode node = null;
        DrbCortexItemClass cl = null;

        // Prepare the DRb node to be processed
        try {
            // First : force loading the model before accessing items.
            DrbCortexModel model = DrbCortexModel.getDefaultModel();
            node = ProcessingUtils.getNodeFromPath(url.getPath());

            if (node == null) {
                throw new IOException("Cannot Instantiate Drb with URI \"" + url.toExternalForm() + "\".");
            }

            cl = model.getClassOf(node);

            if (cl == null) {
                throw new UnsupportedOperationException("Unknown DRB class for product \"" + url.getPath() + "\".");
            }

            logger.info("Recognized class \"" + cl.getLabel() + "\".");

            // Get all values of the metadata properties attached to the item
            // class or any of its super-classes
            properties = cl.listPropertyStrings(METADATA_NAMESPACE + PROPERTY, false);

            // Return immediately if no property value were found
            if (properties == null) {
                logger.warn("Item \"" + cl.getLabel() + "\" has no identifier defined.");
                return null;
            }
        } catch (IOException e) {
            throw new UnsupportedOperationException("Error While decoding drb node", e);
        }

        // retrieve the first extractor
        String property = properties.iterator().next();

        // Filter possible XML markup brackets that could have been encoded
        // in a CDATA section
        property = property.replaceAll("&lt;", "<");
        property = property.replaceAll("&gt;", ">");

        // Create a query for the current metadata extractor
        Query query = new Query(property);

        // Evaluate the XQuery
        DrbSequence sequence = query.evaluate(node);

        // Check that something results from the evaluation: jump to next
        // value otherwise
        if ((sequence == null) || (sequence.getLength() < 1)) {
            return null;
        }

        String identifier = sequence.getItem(0).toString();
        return identifier;

    }

    @Override
    public void run(Product product) {
        String identifier = process(product.getPath());
        if (identifier != null) {
            logger.debug("Found product identifier " + identifier);
            product.setIdentifier(identifier);
        } else {
            logger.warn("No defined identifier - using filename");
            String path = product.getPath().getPath();
            product.setIdentifier((new File(path)).getName());
        }
    }

    @Override
    public void removeProcessing(Product object) {
        // Identifier automatically removed with the product.
    }

}