be.bagofwords.cache.CachesManager Maven / Gradle / Ivy

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Utility classes that are used in the count-db project and other bow-* projects
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package be.bagofwords.cache;

import be.bagofwords.application.ApplicationContext;
import be.bagofwords.application.BowTaskScheduler;
import be.bagofwords.application.memory.MemoryGobbler;
import be.bagofwords.application.memory.MemoryManager;
import be.bagofwords.application.status.StatusViewable;

import java.lang.ref.WeakReference;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public class CachesManager implements MemoryGobbler, StatusViewable {

    private final List> caches;

    public CachesManager(ApplicationContext applicationContext) {
        this.caches = new ArrayList<>();
        applicationContext.getBean(MemoryManager.class).registerMemoryGobbler(this);
        applicationContext.getBean(BowTaskScheduler.class).schedulePeriodicTask(this::updateCaches, 500);
    }

    private void updateCaches() {
        synchronized (caches) {
            for (WeakReference reference : caches) {
                ReadCache readCache = reference.get();
                if (readCache != null) {
                    readCache.updateCachedObjects();
                }
            }
        }
    }

    @Override
    public synchronized long freeMemory() {
        synchronized (caches) {
            for (WeakReference reference : caches) {
                ReadCache readCache = reference.get();
                if (readCache != null) {
                    readCache.moveCachedObjectsToOld();
                }
            }
            return 0; //TODO return actual size of freeded memory
        }
    }

    @Override
    public long getMemoryUsage() {
        return sizeOfAllReadCaches();
    }

    private synchronized long sizeOfAllReadCaches() {
        long result = 0;
        synchronized (caches) {
            for (WeakReference reference : caches) {
                ReadCache readCache = reference.get();
                if (readCache != null) {
                    result += readCache.completeSize();
                }
            }
        }
        return result;
    }


    public synchronized  ReadCache createNewCache(String name, Class objectClass) {
        ReadCache newReadCache = new ReadCache<>(name, objectClass);
        synchronized (caches) {
            caches.add(new WeakReference<>(newReadCache));
        }
        return newReadCache;
    }

    @Override
    public synchronized void printHtmlStatus(StringBuilder sb) {
        sb.append("Caches");
        List sortedCaches = new ArrayList<>();
        synchronized (caches) {
            for (WeakReference reference : caches) {
                ReadCache readCache = reference.get();
                if (readCache != null) {
                    sortedCaches.add(readCache);
                }
            }
        }
        Collections.sort(sortedCaches, (o1, o2) -> -Double.compare(o1.size(), o2.size()));
        for (ReadCache readCache : sortedCaches) {
            double hitRatio = readCache.getNumberOfHits() == 0 ? 0 : readCache.getNumberOfHits() / (double) readCache.getNumberOfFetches();
            sb.append(readCache.getName() + " size=" + readCache.size() + " fetches=" + readCache.getNumberOfFetches() + " hits=" + readCache.getNumberOfHits() + " hitRatio=" + hitRatio);
            sb.append("
");
        }
    }


}