view artifacts/src/main/java/org/dive4elements/river/artifacts/model/FastCrossSectionChunk.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 5f4893db41e4
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 java.util.List;
import java.util.Collections;

import java.io.Serializable;

import org.dive4elements.river.model.CrossSection;

import org.dive4elements.river.model.FastCrossSectionLine;

import org.apache.log4j.Logger;

/**
 * Number of FastCrossSectionLines, e.g. to store in cache and retrieve
 * a single contain CrossSectionLine by its km.
 */
public class FastCrossSectionChunk
implements   Serializable
{
    private static Logger log = Logger.getLogger(FastCrossSectionChunk.class);

    public static final String PREFIX = "FCSC:";
    public static final double KM_RANGE = 1.0;

    protected double startKm;
    protected int    crossSectionId;

    protected List<FastCrossSectionLine> crossSectionLines;

    public FastCrossSectionChunk() {
    }

    public FastCrossSectionChunk(CrossSection cs, double km) {

        crossSectionId = cs.getId();
        startKm = Math.floor(km);
        double stopKm = startKm + KM_RANGE;

        long startTime = System.currentTimeMillis();

        crossSectionLines = cs.getFastLines(startKm, stopKm);

        long stopTime = System.currentTimeMillis();

        if (log.isDebugEnabled()) {
            log.debug("Fetching cross section lines took " +
                (float)(stopTime-startTime)/1000f + " secs.");
        }
    }

    /** Finds the FastCrossSectionLine at km (null if not found). */
    public FastCrossSectionLine getCrossSectionLine(double km) {
        FastCrossSectionLine key = new FastCrossSectionLine(km);
        int pos = Collections.binarySearch(
            crossSectionLines, key, FastCrossSectionLine.KM_CMP);
        return pos < 0 ? null : crossSectionLines.get(pos);
    }

    public static String createHashKey(CrossSection cs, double km) {
        return PREFIX + cs.getId() + ":" + (int)Math.floor(km);
    }

    public String getHashKey() {
        return PREFIX + crossSectionId + ":" + (int)Math.floor(startKm);
    }

    public double getStartKm() {
        return startKm;
    }

    public void setStartKm(double startKm) {
        this.startKm = startKm;
    }

    public double getStopKm() {
        return startKm + KM_RANGE;
    }

    public int getCrossSectionId() {
        return crossSectionId;
    }

    public void setCrossSectionId(int crossSectionId) {
        this.crossSectionId = crossSectionId;
    }
}
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