com.eightkdata.mongowp.bson.netty.pool.GuavaStringPool Maven / Gradle / Ivy

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/*
 * This file is part of MongoWP.
 *
 * MongoWP is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * MongoWP 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 Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with bson-netty. If not, see .
 *
 * Copyright (C) 2016 8Kdata.
 * 
 */

package com.eightkdata.mongowp.bson.netty.pool;

import com.eightkdata.mongowp.bson.netty.annotations.ConservesIndexes;
import com.eightkdata.mongowp.bson.netty.annotations.Tight;
import com.google.common.cache.*;
import io.netty.buffer.ByteBuf;
import javax.annotation.Nonnull;
import javax.inject.Inject;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 *
 */
public class GuavaStringPool extends StringPool {

    private static final Logger LOGGER
            = LoggerFactory.getLogger(GuavaStringPool.class);
    private final LoadingCache cache;

    @Inject
    public GuavaStringPool(StringPoolPolicy heuristic, CacheBuilder cacheBuilder) {
        super(heuristic);
        cache = cacheBuilder
                .removalListener(new MyRemovalListener())
                .build(new MyCacheLoader());
    }

    @Override
    protected String retrieveFromPool(@Tight @ConservesIndexes ByteBuf stringBuf) {
        String result = cache.getIfPresent(stringBuf);
        if (result == null) {
            result = cache.getUnchecked(stringBuf.copy());
        }
        return result;
    }

    private static class MyCacheLoader extends CacheLoader {

        @Override
        public String load(@Nonnull ByteBuf key) {
            return StringPool.getString(key);
        }

    }

    private static class MyRemovalListener implements RemovalListener {

        @Override
        public void onRemoval(RemovalNotification notification) {
            ByteBuf key = notification.getKey();
            if (key == null) {
                throw new IllegalStateException("Unexpected null key");
            }
            boolean release = key.release();
            if (!release) {
                LOGGER.warn("The cached string ByteBuf with value {} was "
                        + "removed but it had more references than expected",
                        notification.getValue()
                );
            }
        }

    }


}