Example usage for com.google.common.hash Hashing consistentHash

Introduction

In this page you can find the example usage for com.google.common.hash Hashing consistentHash.

Prototype

public static int consistentHash(long input, int buckets) 

Source Link

Document

Assigns to input a "bucket" in the range [0, buckets) , in a uniform manner that minimizes the need for remapping as buckets grows.

Usage

From source file:org.apache.niolex.common.guava.GuavaHashing.java

/**
 * @param args/*from w w w.j a  v a 2  s.c  om*/
 */
public static void main(String[] args) {
    // Common Hash
    HashFunction hf = Hashing.goodFastHash(32);
    HashCode code = hf.hashObject(new Person(1, "Jiyun", "Xie", 1984), PersonFunnel.INSTANCE);
    System.out.println("Code1 => " + code.asInt());
    code = hf.hashObject(new Person(1, "Jiyun", "Xie", 1985), PersonFunnel.INSTANCE);
    System.out.println("Code2 => " + code.asInt());
    // Consistent Hashing
    HashFunction hf2 = Hashing.goodFastHash(64);
    code = hf2.hashObject(new Person(1, "Jiyun", "Xie", 1984), PersonFunnel.INSTANCE);
    System.out.println("Code3 => " + code.asLong());
    long hash = code.asLong();
    int bucket = Hashing.consistentHash(code, 100);
    System.out.println("Bucket1 => " + bucket);
    bucket = Hashing.consistentHash(hash, 101);
    System.out.println("Bucket2 => " + bucket);
    for (int i = 0; i < 10; ++i) {
        System.out.println("HashTo5 => " + Hashing.consistentHash(i, 5));
        System.out.println("HashTo6 => " + Hashing.consistentHash(i, 6));
    }
    // BloomFilter
    BloomFilter<Person> friends = BloomFilter.create(PersonFunnel.INSTANCE, 500, 0.02);
    for (int i = 0; i < 500; ++i) {
        friends.put(new Person(i, "Jiyun", "Xie", 1984 + i));
    }
    int k = 0;
    for (int i = 0; i < 500; ++i) {
        if (!friends.mightContain(new Person(i, "Jiyun", "Xie", 1984 + i))) {
            System.out.println("Error1 => " + i);
            ++k;
        }
    }
    System.out.println("fnp => (should be 0)" + ((double) k / 500));
    k = 0;
    for (int i = 0; i < 1000; i += 2) {
        if (friends.mightContain(new Person(i, "Jiyun", "Xie", 1984 + i))) {
            //System.out.println("Error2 => " + i);
            ++k;
        }
    }
    System.out.println("fpp => " + ((double) k / 500));
}

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From source file:google.registry.model.index.EppResourceIndexBucket.java

/**
 * Deterministic function that returns a bucket id based on the resource's roid.
 * NB: At the moment, nothing depends on this being deterministic, so we have the ability to
 * change the number of buckets and utilize a random distribution once we do.
 *///  w  w w .j  a v a2  s.co m
private static long getBucketIdFromEppResource(Key<? extends EppResource> resourceKey) {
    int numBuckets = getEppResourceIndexBucketCount();
    // IDs can't be 0, so add 1 to the hash.
    return Hashing.consistentHash(resourceKey.getName().hashCode(), numBuckets) + 1;
}

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From source file:io.atomix.primitive.partition.Murmur3Partitioner.java

@Override
public PartitionId partition(String key, List<PartitionId> partitions) {
    int hash = Math.abs(Hashing.murmur3_32().hashUnencodedChars(key).asInt());
    return partitions.get(Hashing.consistentHash(hash, partitions.size()));
}

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From source file:info.yangguo.dragon.storage.mysql.algorithm.SingleKeyModuloTableShardingAlgorithm.java

@Override
public String doEqualSharding(final Collection<String> availableTargetNames,
        final ShardingValue<String> shardingValue) {
    int index = Hashing.consistentHash(Hashing.murmur3_32().hashBytes(shardingValue.getValue().getBytes()),
            tbSum);//  w  w w  . j  a  v a2  s  . c om
    for (String each : availableTargetNames) {
        if (each.endsWith(index + "")) {
            return each;
        }
    }
    throw new UnsupportedOperationException();
}

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From source file:info.yangguo.dragon.storage.mysql.algorithm.SingleKeyModuloDatabaseShardingAlgorithm.java

@Override
public String doEqualSharding(final Collection<String> availableTargetNames,
        final ShardingValue<String> shardingValue) {
    int index = Hashing.consistentHash(Hashing.murmur3_32().hashBytes(shardingValue.getValue().getBytes()),
            dbSum);//  w w  w  . j av a  2  s .c o  m
    for (String each : availableTargetNames) {
        if (each.endsWith(index + "")) {
            return each;
        }
    }
    throw new UnsupportedOperationException();
}

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From source file:com.necla.simba.util.ConsistentHash.java

public int hash(String token, int size) {
    return Hashing.consistentHash(Hashing.murmur3_128(SEED).hashString(token), size);
}

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From source file:com.necla.simba.util.ConsistentHash.java

public int hash(int token, int size) {
    return Hashing.consistentHash(Hashing.murmur3_128(SEED).hashInt(token), size);
}

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From source file:com.necla.simba.util.ConsistentHash.java

public String getNode(String id) {
    int bucket = Hashing.consistentHash(Hashing.murmur3_128(SEED).hashString(id), servers.size());
    return servers.get(bucket);
}

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From source file:io.pravega.common.hash.HashHelper.java

public int hashToBucket(String str, int numBuckets) {
    return Hashing.consistentHash(hash.hashUnencodedChars(str), numBuckets);
}

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From source file:org.apache.nifi.controller.queue.clustered.partition.CorrelationAttributePartitioner.java

@Override
public QueuePartition getPartition(final FlowFileRecord flowFile, final QueuePartition[] partitions,
        final QueuePartition localPartition) {
    final int hash = hash(flowFile);

    // The consistentHash method appears to always return a bucket of '1' if there are 2 possible buckets,
    // so in this case we will just use modulo division to avoid this. I suspect this is a bug with the Guava
    // implementation, but it's not clear at this point.
    final int index;
    if (partitions.length < 3) {
        index = hash % partitions.length;
    } else {/*from   ww  w.  j av  a 2s  .  co m*/
        index = Hashing.consistentHash(hash, partitions.length);
    }

    return partitions[index];
}

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