importer.handler.get.ImporterGetHandler.java Source code

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Here is the source code for importer.handler.get.ImporterGetHandler.java

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/*
 * This file is part of Project.
 *
 *  Project is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  Project 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with Project.  If not, see <http://www.gnu.org/licenses/>.
 *  (c) copyright Desmond Schmidt 2014
 */

package importer.handler.get;

import importer.exception.ImporterException;
import importer.handler.ImporterHandler;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import calliope.core.Utils;
import calliope.core.database.Connector;
import importer.constants.Service;
import calliope.core.constants.Database;
import calliope.core.constants.Formats;
import calliope.core.constants.JSONKeys;
import importer.handler.EcdosisMVD;
import org.json.simple.JSONObject;
import org.json.simple.JSONValue;

/**
 * Get a project document from the database
 * @author desmond
 */
public class ImporterGetHandler extends ImporterHandler {
    public void handle(HttpServletRequest request, HttpServletResponse response, String urn)
            throws ImporterException {
        try {
            String prefix = Utils.first(urn);
            urn = Utils.pop(urn);
            if (prefix != null) {
                if (prefix.equals(Service.JSON))
                    new ImporterJSONHandler().handle(request, response, urn);
                else if (prefix.equals(Service.COLLECTION))
                    new ImporterListCollectionHandler().handle(request, response, urn);
            } else
                throw new ImporterException("Invalid urn (prefix was null) " + urn);
        } catch (Exception e) {
            try {
                response.setCharacterEncoding("UTF-8");
                response.getWriter().println(e.getMessage());
            } catch (Exception ex) {
                throw new ImporterException(ex);
            }
        }
    }

    /**
     * Fetch and load an MVD
     * @param db the database 
     * @param docID
     * @return the loaded MVD
     * @throws an ImporterException if not found
     */
    protected EcdosisMVD loadMVD(String db, String docID) throws ImporterException {
        try {
            String data = Connector.getConnection().getFromDb(db, docID);
            if (data.length() > 0) {
                JSONObject doc = (JSONObject) JSONValue.parse(data);
                if (doc != null)
                    return new EcdosisMVD(doc);
            }
            throw new ImporterException("MVD not found " + docID);
        } catch (Exception e) {
            throw new ImporterException(e);
        }
    }

    protected String getVersionTableForUrn(String urn) throws ImporterException {
        try {
            JSONObject doc = loadJSONDocument(Database.CORTEX, urn);
            String fmt = (String) doc.get(JSONKeys.FORMAT);
            if (fmt != null && fmt.startsWith(Formats.MVD)) {
                EcdosisMVD mvd = loadMVD(Database.CORTEX, urn);
                return mvd.mvd.getVersionTable();
            } else if (fmt != null && fmt.equals(Formats.TEXT)) {
                // concoct a version list of length 1
                StringBuilder sb = new StringBuilder();
                String version1 = (String) doc.get(JSONKeys.VERSION1);
                if (version1 == null)
                    throw new ImporterException("Lacks version1 default");
                sb.append("Single version\n");
                String[] parts = version1.split("/");
                for (int i = 0; i < parts.length; i++) {
                    sb.append(parts[i]);
                    sb.append("\t");
                }
                sb.append(parts[parts.length - 1] + " version");
                sb.append("\n");
                return sb.toString();
            } else
                throw new ImporterException("Unknown of null Format");
        } catch (Exception e) {
            throw new ImporterException(e);
        }
    }

    /**
     * Use this method to retrieve the doc just to see its format
     * @param db the database to fetch from
     * @param docID the doc's ID
     * @return a JSON doc as returned by Mongo
     * @throws ImporterException 
     */
    JSONObject loadJSONDocument(String db, String docID) throws ImporterException {
        try {
            String data = Connector.getConnection().getFromDb(db, docID);
            if (data.length() > 0) {
                JSONObject doc = (JSONObject) JSONValue.parse(data);
                if (doc != null)
                    return doc;
            }
            throw new ImporterException("Doc not found " + docID);
        } catch (Exception e) {
            throw new ImporterException(e);
        }
    }
}