compare.handler.get.TableInfoHandler.java Source code

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Here is the source code for compare.handler.get.TableInfoHandler.java

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/*
 * This file is part of Compare.
 *
 *  Compare 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.
 *
 *  Compare 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 Copare.  If not, see <http://www.gnu.org/licenses/>.
 *  (c) copyright Desmond Schmidt 2016
 */

package compare.handler.get;

import calliope.core.constants.JSONKeys;
import compare.constants.Params;
import java.util.Map;
import compare.exception.CompareException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.json.simple.JSONArray;

/**
 * Return information about a potential table but don't generate it
 * @author desmond
 */
import calliope.core.handler.EcdosisMVD;
import compare.constants.Database;

public class TableInfoHandler extends TableHandler {
    static final int CHUNK = 50;

    /**
     * Handle a request to get some metadata for a document
     * @param request the http request
     * @param response the response
     * @param urn the current urn (ignored)
     * @throws CompareException if loading of MVD failed
     */
    public void handle(HttpServletRequest request, HttpServletResponse response, String urn)
            throws CompareException {
        Map map = request.getParameterMap();
        docid = request.getParameter(JSONKeys.DOCID);
        version1 = getStringOption(map, Params.VERSION1, "");
        String json = "{}";
        try {
            if (docid != null && docid.length() > 0) {
                EcdosisMVD mvd = loadMVD(Database.CORTEX, docid);
                String selected = getStringOption(map, Params.SELECTED, ALL);
                String baseVersion = selectVersion1(mvd, selected);
                short base = mvd.getBaseVersion(baseVersion);
                int baseLen = getBaseVersionLen(mvd, base);
                int[] offsets = mvd.measureTable(base);
                int numSegs = Math.round((float) offsets.length / (float) CHUNK);
                if (numSegs == 0)
                    numSegs = 1;
                int[] segs = new int[numSegs + 1];
                if (numSegs == 2) {
                    segs[0] = 0;
                    segs[1] = baseLen;
                } else {
                    for (int i = 0; i < numSegs; i++)
                        segs[i] = offsets[i * CHUNK];
                }
                segs[segs.length - 1] = baseLen;
                JSONArray arr = new JSONArray();
                for (int i = 0; i < segs.length; i++)
                    arr.add(segs[i]);
                json = arr.toJSONString();
            } else
                throw new Exception("CORTEX mvd " + docid + " not found");
            response.setContentType("application/json;charset=UTF-8");
            response.getWriter().println(json);
        } catch (Exception e) {
            throw new CompareException(e);
        }
    }
}