solr/core/src/java/org/apache/solr/search/SolrCacheHolder.java

/*
 * 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 java.lang.invoke.MethodHandles;
import java.util.Map;
import java.util.Set;

import com.codahale.metrics.MetricRegistry;
import org.apache.solr.core.PackageBag.PackageInfo;
import org.apache.solr.core.PackageListeners;
import org.apache.solr.core.PluginInfo;
import org.apache.solr.metrics.SolrMetricManager;
import org.apache.solr.metrics.SolrMetricProducer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class SolrCacheHolder<K, V> implements SolrCache<K,V> {
  private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());


  private CacheConfig.CacheInfo info;
  protected volatile SolrCache<K, V> delegate;



  public SolrCacheHolder(CacheConfig.CacheInfo cacheInfo) {
    this.info = cacheInfo;
    this.delegate = cacheInfo.cache;

    if (info.pkg != null) {
      info.core.getListenerRegistry().addListener(new PackageListeners.Listener() {
        @Override
        public String packageName() {
          return info.pkg;
        }

        @Override
        public PluginInfo pluginInfo() {
          return info.cfg.args;
        }

        @Override
        public PackageInfo packageInfo() {
          return info.packageInfo;
        }

        @Override
        public void changed(PackageInfo pkgInfo) {
          reloadCache(pkgInfo);
        }
      });
    }
  }

  private void reloadCache(PackageInfo packageInfo) {
    int znodeVersion = info.packageInfo == null ? -1 : info.packageInfo.znodeVersion;
    if (packageInfo.znodeVersion > znodeVersion) {
      log.info("Cache {} being reloaded, package: {} version: {} ", delegate.getClass().getSimpleName(), packageInfo.name, packageInfo.version);
      info = new CacheConfig.CacheInfo(info.cfg, info.core);
      info.packageInfo = packageInfo;
      delegate.close();
      delegate = info.cache;
      if(metricsInfo != null){
        metricsInfo.init(delegate);

      }
    }
  }

  public int size() {
    return delegate.size();
  }

  public V put(K key, V value) {
    return delegate.put(key, value);

  }

  public V get(K key) {
    return delegate.get(key);
  }

  public void clear() {
    delegate.clear();
  }

  @Override
  public void setState(State state) {
    delegate.setState(state);
  }

  @Override
  public State getState() {
    return delegate.getState();
  }

  @Override
  public void warm(SolrIndexSearcher searcher, SolrCache<K, V> old) {
    if (old instanceof SolrCacheHolder) old = ((SolrCacheHolder) old).get();
    delegate.warm(searcher, old);

  }

  public SolrCache<K, V> get() {
    return delegate;
  }

  public void close() {
    delegate.close();
  }

  @Override
  public int getMaxSize() {
    return delegate.getMaxSize();
  }

  @Override
  public void setMaxSize(int maxSize) {
    delegate.setMaxSize(maxSize);
  }

  @Override
  public int getMaxRamMB() {
    return delegate.getMaxRamMB();
  }

  @Override
  public void setMaxRamMB(int maxRamMB) {
    delegate.setMaxRamMB(maxRamMB);
  }

  public void warm(SolrIndexSearcher searcher, SolrCacheHolder src) {
    delegate.warm(searcher, src.get());
  }

  @Override
  public Object init(Map args, Object persistence, CacheRegenerator regenerator) {
    return null;
  }

  @Override
  public String name() {
    return delegate.name();
  }


  @Override
  public String getName() {
    return delegate.getName();
  }

  @Override
  public MetricRegistry getMetricRegistry() {
    return delegate.getMetricRegistry();
  }

  @Override
  public Set<String> getMetricNames() {
    return delegate.getMetricNames();
  }

  @Override
  public String getDescription() {
    return delegate.getDescription();
  }

  @Override
  public Category getCategory() {
    return delegate.getCategory();
  }


  private MetricsInfo metricsInfo;

  public static class MetricsInfo {
    final SolrMetricManager manager;
    final String registry;
    final String tag;
    final String scope;

    MetricsInfo(SolrMetricManager manager, String registry, String tag, String scope) {
      this.manager = manager;
      this.registry = registry;
      this.tag = tag;
      this.scope = scope;
    }

    public void init(SolrMetricProducer metricProducer) {
      metricProducer.initializeMetrics(manager,registry,tag,scope);
    }
  }

  @Override
  public void initializeMetrics(SolrMetricManager manager, String registry, String tag, String scope) {
    this.metricsInfo = new MetricsInfo(manager, registry, tag, scope);
    delegate.initializeMetrics(manager, registry, tag, scope);

  }
}