io.geobit.chain.providers.block.BlocksCache.java Source code

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Here is the source code for io.geobit.chain.providers.block.BlocksCache.java

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/*
 * The MIT License (MIT)
 * 
 * Copyright (c) 2014 geobit.io 
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package io.geobit.chain.providers.block;

import static io.geobit.common.statics.Log.log;
import io.geobit.chain.providers.GetPut;
import io.geobit.common.entity.Block;

import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;

import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;

public class BlocksCache implements GetPut<Integer, Block> {
    private Integer higherSeen = 0;
    private Map<Integer, Block> confirmedBlocks;
    private LoadingCache<Integer, Block> recentBlocks;

    public BlocksCache() {
        super();
        confirmedBlocks = new HashMap<Integer, Block>(); /* all the confirmed blocks could fit in HashMap */

        recentBlocks = CacheBuilder.newBuilder().maximumSize(100)
                .expireAfterWrite(5,
                        TimeUnit.MINUTES) /* expiring after five minutes, if recent, could be orphaned block */
                .build(new CacheLoader<Integer, Block>() {
                    public Block load(Integer height) { /* never been called */
                        log("BlockAndTransactionDispatcher recent blocks cache. key " + height);
                        throw new RuntimeException(
                                "BlockAndTransactionDispatcher recent blocks cache address invalid");
                    }
                });
    }

    public Block get(Integer height) {
        Block b = confirmedBlocks.get(height);
        if (b != null)
            return b;
        b = recentBlocks.getIfPresent(height);
        if (b != null)
            return b;
        return null;
    }

    public void put(Integer height, Block b) {
        if (b != null) {
            int blockHeight = b.getHeight();
            if (blockHeight < (higherSeen - 10))
                confirmedBlocks.put(height, b); //block confirmed for sure;
            else
                recentBlocks.put(height, b); //expiring cache for possible expiring blocks
            if (higherSeen < blockHeight)
                higherSeen = blockHeight;
        }

    }

    @Override
    public String toString() {
        return "BlocksCache [higherSeen=" + higherSeen + ", confirmedBlocks.size()=" + confirmedBlocks.size()
                + ", recentBlocks.size()=" + recentBlocks.size() + "]";
    }

}