/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.solr.search;
import org.apache.solr.core.SolrCore;
import org.apache.solr.core.SolrException;
import org.apache.solr.util.NamedList;
import java.util.*;
import java.util.concurrent.atomic.AtomicLong;
import java.io.IOException;
import java.net.URL;
/**
* @author yonik
* @version $Id: LRUCache.java 472574 2006-11-08 18:25:52Z yonik $
*/
public class LRUCache implements SolrCache {
/* An instance of this class will be shared across multiple instances
* of an LRUCache at the same time. Make sure everything is thread safe.
*/
private static class CumulativeStats {
AtomicLong lookups = new AtomicLong();
AtomicLong hits = new AtomicLong();
AtomicLong inserts = new AtomicLong();
AtomicLong evictions = new AtomicLong();
}
private CumulativeStats stats;
// per instance stats. The synchronization used for the map will also be
// used for updating these statistics (and hence they are not AtomicLongs
private long lookups;
private long hits;
private long inserts;
private long evictions;
private Map map;
private String name;
private int autowarmCount;
private State state;
private CacheRegenerator regenerator;
private String description="LRU Cache";
public Object init(Map args, Object persistence, CacheRegenerator regenerator) {
state=State.CREATED;
this.regenerator = regenerator;
name = (String)args.get("name");
String str = (String)args.get("size");
final int limit = str==null ? 1024 : Integer.parseInt(str);
str = (String)args.get("initialSize");
final int initialSize = Math.min(str==null ? 1024 : Integer.parseInt(str), limit);
str = (String)args.get("autowarmCount");
autowarmCount = str==null ? 0 : Integer.parseInt(str);
description = "LRU Cache(maxSize=" + limit + ", initialSize=" + initialSize;
if (autowarmCount>0) {
description += ", autowarmCount=" + autowarmCount
+ ", regenerator=" + regenerator;
}
description += ')';
map = new LinkedHashMap(initialSize, 0.75f, true) {
protected boolean removeEldestEntry(Map.Entry eldest) {
if (size() > limit) {
// increment evictions regardless of state.
// this doesn't need to be synchronized because it will
// only be called in the context of a higher level synchronized block.
evictions++;
stats.evictions.incrementAndGet();
return true;
}
return false;
}
};
if (persistence==null) {
// must be the first time a cache of this type is being created
persistence = new CumulativeStats();
}
stats = (CumulativeStats)persistence;
return persistence;
}
public String name() {
return name;
}
public int size() {
synchronized(map) {
return map.size();
}
}
public synchronized Object put(Object key, Object value) {
if (state == State.LIVE) {
stats.inserts.incrementAndGet();
}
synchronized (map) {
// increment local inserts regardless of state???
// it does make it more consistent with the current size...
inserts++;
return map.put(key,value);
}
}
public Object get(Object key) {
synchronized (map) {
Object val = map.get(key);
if (state == State.LIVE) {
// only increment lookups and hits if we are live.
lookups++;
stats.lookups.incrementAndGet();
if (val!=null) {
hits++;
stats.hits.incrementAndGet();
}
}
return val;
}
}
public void clear() {
synchronized(map) {
map.clear();
}
}
public void setState(State state) {
this.state = state;
}
public State getState() {
return state;
}
public void warm(SolrIndexSearcher searcher, SolrCache old) throws IOException {
if (regenerator==null) return;
LRUCache other = (LRUCache)old;
// warm entries
if (autowarmCount != 0) {
Object[] keys,vals = null;
// Don't do the autowarming in the synchronized block, just pull out the keys and values.
synchronized (other.map) {
int sz = other.map.size();
if (autowarmCount!=-1) sz = Math.min(sz,autowarmCount);
keys = new Object[sz];
vals = new Object[sz];
Iterator iter = other.map.entrySet().iterator();
// iteration goes from oldest (least recently used) to most recently used,
// so we need to skip over the oldest entries.
int skip = other.map.size() - sz;
for (int i=0; i<skip; i++) iter.next();
for (int i=0; i<sz; i++) {
Map.Entry entry = (Map.Entry)iter.next();
keys[i]=entry.getKey();
vals[i]=entry.getValue();
}
}
// autowarm from the oldest to the newest entries so that the ordering will be
// correct in the new cache.
for (int i=0; i<keys.length; i++) {
try {
boolean continueRegen = regenerator.regenerateItem(searcher, this, old, keys[i], vals[i]);
if (!continueRegen) break;
}
catch (Throwable e) {
SolrException.log(log,"Error during auto-warming of key:" + keys[i], e);
}
}
}
}
public void close() {
}
//////////////////////// SolrInfoMBeans methods //////////////////////
public String getName() {
return LRUCache.class.getName();
}
public String getVersion() {
return SolrCore.version;
}
public String getDescription() {
return description;
}
public Category getCategory() {
return Category.CACHE;
}
public String getSourceId() {
return "$Id: LRUCache.java 472574 2006-11-08 18:25:52Z yonik $";
}
public String getSource() {
return "$URL: https://svn.apache.org/repos/asf/incubator/solr/branches/branch-1.1/src/java/org/apache/solr/search/LRUCache.java $";
}
public URL[] getDocs() {
return null;
}
// returns a ratio, not a percent.
private static String calcHitRatio(long lookups, long hits) {
if (lookups==0) return "0.00";
if (lookups==hits) return "1.00";
int hundredths = (int)(hits*100/lookups); // rounded down
if (hundredths < 10) return "0.0" + hundredths;
return "0." + hundredths;
/*** code to produce a percent, if we want it...
int ones = (int)(hits*100 / lookups);
int tenths = (int)(hits*1000 / lookups) - ones*10;
return Integer.toString(ones) + '.' + tenths;
***/
}
public NamedList getStatistics() {
NamedList lst = new NamedList();
synchronized (map) {
lst.add("lookups", lookups);
lst.add("hits", hits);
lst.add("hitratio", calcHitRatio(lookups,hits));
lst.add("inserts", inserts);
lst.add("evictions", evictions);
lst.add("size", map.size());
}
long clookups = stats.lookups.get();
long chits = stats.hits.get();
lst.add("cumulative_lookups", clookups);
lst.add("cumulative_hits", chits);
lst.add("cumulative_hitratio", calcHitRatio(clookups,chits));
lst.add("cumulative_inserts", stats.inserts.get());
lst.add("cumulative_evictions", stats.evictions.get());
return lst;
}
public String toString() {
return name + getStatistics().toString();
}
}