view artifacts/src/main/java/org/dive4elements/river/artifacts/model/FastCrossSectionLineFactory.java @ 8659:af415396d9ca

(issue1803) Use MD5 instead of a homegrown hashing algorithm For creating a digest of the parametrization we should use an algorithm that does not create collisions if there are small changes in the parametrization so that wrong results are returned.
author Andre Heinecke <andre.heinecke@intevation.de>
date Thu, 02 Apr 2015 17:40:18 +0200
parents af13ceeba52a
children 0a5239a1e46e
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/* Copyright (C) 2011, 2012, 2013 by Bundesanstalt für Gewässerkunde
 * Software engineering by Intevation GmbH
 *
 * This file is Free Software under the GNU AGPL (>=v3)
 * and comes with ABSOLUTELY NO WARRANTY! Check out the
 * documentation coming with Dive4Elements River for details.
 */

package org.dive4elements.river.artifacts.model;

import org.dive4elements.river.artifacts.cache.CacheFactory;

import org.dive4elements.river.model.CrossSection;

import org.dive4elements.river.model.FastCrossSectionLine;

import net.sf.ehcache.Cache;
import net.sf.ehcache.Element;

import java.util.List;

import org.apache.log4j.Logger;

public class FastCrossSectionLineFactory
{
    private static Logger log =
        Logger.getLogger(FastCrossSectionLineFactory.class);

    public static final String CACHE_NAME = "fast-cross-section-lines";

    private FastCrossSectionLineFactory() {
    }

    public static FastCrossSectionLine getCrossSectionLine(
        CrossSection cs,
        double       km
    ) {
        Cache cache = CacheFactory.getCache(CACHE_NAME);

        boolean debug = log.isDebugEnabled();

        if (cache == null) {
            if (debug) {
                log.debug("No cross section chunk cache configured.");
            }
            List<FastCrossSectionLine> lines = cs.getFastLines(km, km);
            return lines.isEmpty() ? null : lines.get(0);
        }

        String cacheKey = FastCrossSectionChunk.createHashKey(cs, km);

        Element element = cache.get(cacheKey);

        FastCrossSectionChunk fcsc;

        if (element != null) {
            if (debug) {
                log.debug("Found cross section chunk in cache id: " +
                    cs.getId() + " km: " + km);
            }

            fcsc = (FastCrossSectionChunk)element.getValue();
        }
        else {
            if (debug) {
                log.debug("Not found cross section chunk in cache id: " +
                    cs.getId() + " km: " + km + " -> loading");
            }
            fcsc = new FastCrossSectionChunk(cs, km);
            element = new Element(cacheKey, fcsc);
            cache.put(element);
        }

        return fcsc.getCrossSectionLine(km);
    }
}
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