org.jboss.resteasy.client.jaxrs.cache.LightweightBrowserCache Maven / Gradle / Ivy

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package org.jboss.resteasy.client.jaxrs.cache;

import java.util.concurrent.atomic.AtomicLong;

import jakarta.ws.rs.core.MediaType;
import jakarta.ws.rs.core.MultivaluedMap;

/**
 * In-memory BrowserCache. Uses an underlying cache, with ConcurrentMapCache as
 * the default. You specify maximum bytes you want the cache to have. The
 * default is 2Megabytes. If the cache exceeds this amount, it is wiped clean.
 * This rather draconian approach to cache reaping is to avoid synchronization
 * that you would normally have to do in a sophisticated cache.
 * 
 * With high concurrent access, because this is not a sophisticated cache,
 * sometimes a cache entry may be lost. It is consistent though.
 *
 * @author Bill Burke
 * @version $Revision: 1 $
 */
public class LightweightBrowserCache implements BrowserCache {

    protected long maxBytes = 2000000; // 2 meg default
    protected BrowserCache internalCache = null;
    protected AtomicLong bytes = new AtomicLong(0);

    public LightweightBrowserCache() {
        this(new MapCache());
    }

    public LightweightBrowserCache(final BrowserCache cache) {
        this.internalCache = cache;
    }

    public BrowserCache getInternalCache() {
        return internalCache;
    }

    public void setInternalCache(BrowserCache internalCache) {
        this.internalCache = internalCache;
    }

    public long getMaxBytes() {
        return maxBytes;
    }

    public void setMaxBytes(long maxBytes) {
        this.maxBytes = maxBytes;
    }

    public Entry getAny(String key) {
        return internalCache.getAny(key);
    }

    public Entry remove(String key, MediaType type) {
        Entry entry = internalCache.remove(key, type);
        if (entry != null)
            bytes.addAndGet(-1 * entry.getCached().length);
        return entry;
    }

    public long getByteCount() {
        return bytes.get();
    }

    public Entry get(String key, MediaType accept) {
        return internalCache.get(key, accept);
    }

    public Entry put(String key, MediaType mediaType,
            MultivaluedMap headers, byte[] cached, int expires,
            String etag, String lastModified) {
        Entry previousValue = internalCache.get(key, mediaType);

        int sizeDiff = -1;
        if (previousValue == null)
            sizeDiff = cached.length;
        else
            sizeDiff = cached.length - previousValue.getCached().length;

        if (bytes.addAndGet(sizeDiff) > maxBytes) {
            clear();
            bytes.addAndGet(sizeDiff);
        }
        return internalCache.put(key, mediaType, headers, cached, expires, etag, lastModified);
    }

    public void clear() {
        internalCache.clear();
        bytes.set(0);
    }
}