io.fluo.core.impl.TxInfoCache.java Source code

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Here is the source code for io.fluo.core.impl.TxInfoCache.java

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/*
 * Copyright 2014 Fluo authors (see AUTHORS)
 *
 * Licensed 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 io.fluo.core.impl;

import io.fluo.api.data.Bytes;
import io.fluo.api.data.Column;

import java.util.concurrent.TimeUnit;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.Weigher;

public class TxInfoCache {

    final static int CACHE_TIMEOUT_MIN = 24 * 60;

    private static class TxStatusWeigher implements Weigher<PrimaryRowColumn, TxInfo> {
        @Override
        public int weigh(PrimaryRowColumn key, TxInfo value) {
            return key.weight() + (value.lockValue == null ? 0 : value.lockValue.length) + 24;
        }
    }

    private final Cache<PrimaryRowColumn, TxInfo> cache;
    private final Environment env;

    TxInfoCache(Environment env) {
        cache = CacheBuilder.newBuilder().expireAfterAccess(CACHE_TIMEOUT_MIN, TimeUnit.MINUTES)
                .maximumWeight(10000000).weigher(new TxStatusWeigher()).concurrencyLevel(10).build();
        this.env = env;
    }

    public TxInfo getTransactionInfo(final Bytes prow, final Column pcol, final long startTs) {
        return getTransactionInfo(new PrimaryRowColumn(prow, pcol, startTs));
    }

    public TxInfo getTransactionInfo(PrimaryRowColumn key) {

        TxInfo txInfo = cache.getIfPresent(key);
        if (txInfo == null) {
            txInfo = TxInfo.getTransactionInfo(env, key.prow, key.pcol, key.startTs);
            if (txInfo.status == TxStatus.ROLLED_BACK || txInfo.status == TxStatus.COMMITTED) {
                // only cache for these statuses which are not expected to change, other status can change over time
                cache.put(key, txInfo);
            }
        }

        return txInfo;
    }
}