Java Hashing.murmur3_128方法代碼示例

import com.google.common.hash.Hashing; //導入方法依賴的package包/類
public FastBloomFilter(int bits, int numberHashFunctions) {
	bs = new BitSet(bits);
	Random r = new Random(System.currentTimeMillis());
	hashFunctions = new HashFunction[numberHashFunctions];
	for (int i=0; i<numberHashFunctions; ++i) {
		hashFunctions[i] = Hashing.murmur3_128(r.nextInt());
	}
	capacity = bits;
}
 

import com.google.common.hash.Hashing; //導入方法依賴的package包/類
@JsonCreator
public Function0(@JsonProperty("seed") int seed,
                 @JsonProperty("fiberNum") int fiberNum)
{
    this.seed = seed;
    this.fiberNum = fiberNum;
    this.hasher = Hashing.murmur3_128(seed);
}
 

import com.google.common.hash.Hashing; //導入方法依賴的package包/類
private FeatureHash(int hashBucketSize,
                    int hashSeed,
                    String hashFeaturePrefix) {
    this.hashBucketSize = hashBucketSize;
    this.hashFeaturePrefix = hashFeaturePrefix;
    this.murmurHash =  Hashing.murmur3_128(hashSeed);
}
 

import com.google.common.hash.Hashing; //導入方法依賴的package包/類
public static HashFunction forName(String name) {
    switch (name) {
        case "murmur3_32":
            return Hashing.murmur3_32();
        case "murmur3_128":
            return Hashing.murmur3_128();
        case "crc32":
            return Hashing.crc32();
        case "md5":
            return Hashing.md5();
        default:
            throw new IllegalArgumentException("Can't find hash function with name " + name);
    }
}
 

import com.google.common.hash.Hashing; //導入方法依賴的package包/類
/** Return the hash function corresponding to a given message-digest algorithm given by name.
 *
 * @param messageDigest a message-digest algorithm (e.g., <code>MurmurHash3</code> or <code>MD5</code>); {@code null} if {@code messageDigest} is the empty string.
 */
@SuppressWarnings("deprecation")
public final static HashFunction forName(final String messageDigest) throws NoSuchAlgorithmException {
	if ("".equals(messageDigest)) return null;
	if ("MD5".equalsIgnoreCase(messageDigest)) return Hashing.md5();
	if ("MurmurHash3".equalsIgnoreCase(messageDigest)) return Hashing.murmur3_128();
	throw new NoSuchAlgorithmException("Unknown hash function " + messageDigest);
}
 

import com.google.common.hash.Hashing; //導入方法依賴的package包/類
public RendezvousHash(Funnel<N> nodeFunnel, Collection<N> init) {
  this.hasher = Hashing.murmur3_128();
  this.nodeFunnel = nodeFunnel;

  nodeList.addAll(init);
}
 

import com.google.common.hash.Hashing; //導入方法依賴的package包/類
public static void main(String []args) {
        FeatureHash featureHash = FeatureHash.build(10, 111311, "hash_").withDelim(",", ":");
        String featureline = "1:1,2:1,3:1,4:1,5:1,6:1,7:1,8:1,9:1";
        List<String> flist = Lists.newArrayList(StringUtils.split("1,2,3,4,5,6,7,8,9", ","));
        List<Tuple<String, Float>> ftlist = new ArrayList<>();
        for (int i = 1; i <= 9; i++) {
            ftlist.add(new Tuple<>(i + "", 1.0f));
        }
        System.out.println("feature line:" + featureline);
        System.out.println("hash map 2 map:" + featureHash.hashMap2Map(parse(featureline, ",", ":")));
        System.out.println("hash map 2 map:" + featureHash.hashMap2Map(parse(featureline, ",", ":")));

        System.out.println("hash list 2 map:" + featureHash.hashList2Map(flist));
        System.out.println("hash list 2 map:" + featureHash.hashList2Map(flist));

        System.out.println("hash tuple list 2 map:" + featureHash.hashPairList2Map(ftlist));
        System.out.println("hash tuple list 2 map:" + featureHash.hashPairList2Map(ftlist));

        System.out.println("hash line 2 map:" + featureHash.hashLine2Map(featureline));
        System.out.println("hash line 2 map:" + featureHash.hashLine2Map(featureline));

        System.out.println("hash map 2 line:" + featureHash.hashMap2Line(parse(featureline, ",", ":")));
        System.out.println("hash map 2 line:" + featureHash.hashMap2Line(parse(featureline, ",", ":")));

        System.out.println("hash list 2 line:" + featureHash.hashList2Line(flist));
        System.out.println("hash list 2 line:" + featureHash.hashList2Line(flist));

        System.out.println("hash line 2 line:" + featureHash.hashLine2Line(featureline));
        System.out.println("hash line 2 line:" + featureHash.hashLine2Line(featureline));



        int time = 10000000;
        int size = 10;
        long start = System.currentTimeMillis();
        int cnt[] = new int[size];
        int signcnt[] = new int[2];

        HashFunction hashFunction = Hashing.murmur3_128(111);
        for (int i = 0; i < time; i++) {
//            cnt[featureHash.hash("fsfdsfdsf" + i) % size] ++;
//            signcnt[featureHash.signhash("fsfdsfdsf" + i) + 1] ++;

            long longhash = hashFunction.hashString("fsfdsfdsf" + i,
                    Charset.defaultCharset()).asLong();
            int fhash = (int)((longhash & 0x7fffffffL) % size);
            float signhash = 2.0f * ((longhash & 0x10000000000L) >> 40) - 1.0f;
            cnt[fhash] ++;
            int sign = 0;
            if (signhash < 0) {
                sign = 0;
            } else {
                sign = 1;
            }
            signcnt[sign] ++;
        }
        long end = System.currentTimeMillis();
        System.out.println("takes:" + time * 1000. / (end - start));

        for (int i = 0; i < size; i++) {
            System.out.println(i + ":" + cnt[i] * 1.0 / time);
        }

        System.out.println(signcnt[0] * 1.0 / time);
        System.out.println(signcnt[1] * 1.0 / time);

//        for (int i = 0; i < 20; i++) {
//            System.out.println(featureHash.hash("xx"));
//            System.out.println(featureHash.hash("yy"));
//        }
    }