org.apache.avro

Class SchemaNormalization

java.lang.Object

org.apache.avro.SchemaNormalization

public class SchemaNormalization
extends Object

Collection of static methods for generating the cannonical form of schemas (see toParsingForm(org.apache.avro.Schema)) -- and fingerprints of cannonical forms (fingerprint(java.lang.String, byte[])).

Method Summary

Methods

Modifier and Type	Method and Description
static byte[]	fingerprint(String fpName, byte[] data) Returns a fingerprint of a string of bytes.
static long	fingerprint64(byte[] data) Returns the 64-bit Rabin Fingerprint (as recommended in the Avro spec) of a byte string.
static byte[]	parsingFingerprint(String fpName, Schema s) Returns fingerprint(java.lang.String, byte[]) applied to the parsing canonical form of the supplied schema.
static long	parsingFingerprint64(Schema s) Returns fingerprint64(byte[]) applied to the parsing canonical form of the supplied schema.
static String	toParsingForm(Schema s) Returns "Parsing Canonical Form" of a schema as defined by Avro spec.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

toParsingForm

public static String toParsingForm(Schema s)

Returns "Parsing Canonical Form" of a schema as defined by Avro spec.

fingerprint

public static byte[] fingerprint(String fpName,
                 byte[] data)
                          throws NoSuchAlgorithmException

Returns a fingerprint of a string of bytes. This string is presumed to contain a canonical form of a schema. The algorithm used to compute the fingerprint is selected by the argument fpName. If fpName equals the string "CRC-64-AVRO", then the result of fingerprint64(byte[]) is returned in little-endian format. Otherwise, fpName is used as an algorithm name for MessageDigest.getInstance(String), which will throw NoSuchAlgorithmException if it doesn't recognize the name.

Recommended Avro practice dictiates that "CRC-64-AVRO" is used for 64-bit fingerprints, "MD5" is used for 128-bit fingerprints, and "SHA-256" is used for 256-bit fingerprints.

Throws:

NoSuchAlgorithmException

fingerprint64

public static long fingerprint64(byte[] data)

Returns the 64-bit Rabin Fingerprint (as recommended in the Avro spec) of a byte string.

parsingFingerprint

public static byte[] parsingFingerprint(String fpName,
                        Schema s)
                                 throws NoSuchAlgorithmException

Returns fingerprint(java.lang.String, byte[]) applied to the parsing canonical form of the supplied schema.

Throws:

NoSuchAlgorithmException

parsingFingerprint64

public static long parsingFingerprint64(Schema s)

Returns fingerprint64(byte[]) applied to the parsing canonical form of the supplied schema.