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/**
* HashARC
* an Adaptive Replacement Cache for objects that can be compared using hashing
* Copyright 2009 by Michael Peter Christen, mc@yacy.net, Frankfurt a. M., Germany
* First released 17.04.2009 at http://yacy.net
*
* $LastChangedDate$
* $LastChangedRevision$
* $LastChangedBy$
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program in the file lgpl21.txt
* If not, see <http://www.gnu.org/licenses/>.
*/
package net.yacy.cora.storage;
import java.util.Collections;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Random;
public final class HashARC<K, V> extends SimpleARC<K, V> implements Map<K, V>, Iterable<Map.Entry<K, V>>, ARC<K, V> {
public final static boolean accessOrder = false; // if false, then a insertion-order is used
public HashARC(final int cacheSize) {
this.cacheSize = cacheSize / 2;
super.levelA = Collections.synchronizedMap(new LinkedHashMap<K, V>(1, 0.1f, accessOrder) {
private static final long serialVersionUID = 1L;
@Override protected boolean removeEldestEntry(final Map.Entry<K, V> eldest) {
return size() > HashARC.this.cacheSize;
}
});
this.levelB = Collections.synchronizedMap(new LinkedHashMap<K, V>(1, 0.1f, accessOrder) {
private static final long serialVersionUID = 1L;
@Override protected boolean removeEldestEntry(final Map.Entry<K, V> eldest) {
return size() > HashARC.this.cacheSize;
}
});
}
public static void main(final String[] args) {
final Random r = new Random();
final int testsize = 10000;
final ARC<String, String> a = new HashARC<String, String>(testsize * 2);
final Map<String, String> b = new HashMap<String, String>();
String key, value;
for (int i = 0; i < testsize; i++) {
key = "k" + r.nextInt();
value = "v" + r.nextInt();
a.insertIfAbsent(key, value);
b.put(key, value);
}
// now put half of the entries AGAIN into the ARC
int h = testsize / 2;
for (final Map.Entry<String, String> entry: b.entrySet()) {
a.put(entry.getKey(), entry.getValue());
if (h-- <= 0) break;
}
// test correctness
for (final Map.Entry<String, String> entry: b.entrySet()) {
if (!a.containsKey(entry.getKey())) {
System.out.println("missing: " + entry.getKey());
continue;
}
if (!a.get(entry.getKey()).equals(entry.getValue())) {
System.out.println("wrong: a = " + entry.getKey() + "," + a.get(entry.getKey()) + "; v = " + entry.getValue());
}
}
System.out.println("finished test!");
}
}
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