Mercurial > dive4elements > gnv-client

annotate geo-backend/src/main/java/de/intevation/gnv/geobackend/util/RedundancyRemover.java @ 895:eb777022b628

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Integrated a CacheCleaner that will cleanup the SQL-Cache if necessary geo-backend/trunk@958 c6561f87-3c4e-4783-a992-168aeb5c3f6f
author Tim Englich <tim.englich@intevation.de>
date Tue, 20 Apr 2010 12:42:17 +0000
parents b757def3ff55
children ebeb56428409
rev   line source
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1 package de.intevation.gnv.geobackend.util;
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2
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3 import java.util.LinkedHashMap;
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4 import java.util.Map;
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5
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6 /**
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7 * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
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8 */
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9 public final class RedundancyRemover
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10 extends LinkedHashMap
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11 {
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12 /** ceil(1029 * 1.75) = 1801, which is prime
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13 * -&gt; suitable for a hash map slot size.
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14 */
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15 public static final int DEFAULT_LOOKBACK =
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16 Integer.getInteger(
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17 "de.intevation.gnv.geobackend.util.RedundancyRemover.lookback",
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18 1029);
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19
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20 private int maxCapacity;
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21 private int removed;
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22
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23 public RedundancyRemover() {
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24 this(DEFAULT_LOOKBACK);
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25 }
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26
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27 public RedundancyRemover(int maxCapacity) {
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28 super((int)Math.ceil(maxCapacity * 1.75f));
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29 this.maxCapacity = maxCapacity;
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30 }
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31
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32 protected boolean removeEldestEntry(Map.Entry eldest) {
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33 return size() > maxCapacity;
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34 }
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35
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36 public int numRemoved() {
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37 return removed;
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38 }
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39
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40 public Object filter(Object object) {
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41 if (object == null) {
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42 return object;
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43 }
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44 Object old = get(object);
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45
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46 if (old != null) {
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47 if (old != object) { // count only identical
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48 ++removed;
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49 }
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50 return old;
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51 }
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52 put(object, object);
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53 return object;
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54 }
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55 }
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56 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
http://dive4elements.wald.intevation.org