Package org.apache.nifi.avro

Class NonCachingDatumReader<T>

java.lang.Object
org.apache.avro.generic.GenericDatumReader<T>
org.apache.nifi.avro.NonCachingDatumReader<T>
All Implemented Interfaces:
org.apache.avro.io.DatumReader<T>
public class NonCachingDatumReader<T> extends org.apache.avro.generic.GenericDatumReader<T>
Override the GenericDatumReader to provide a much more efficient implementation of #readString. The one that is provided by GenericDatumReader performs very poorly in some cases because it uses an IdentityHashMap with the key being the Schema so that it can stash away the "stringClass" but that performs far worse than just calling JsonNode#getProp. I.e., readString(Object, Schema, Decoder) in GenericDatumReader calls #getStringClass, which uses an IdentityHashMap to cache results in order to avoid calling findStringClass(Schema). However, findStringClass(Schema) is much more efficient than using an IdentityHashMap anyway. Additionally, the performance of findStringClass(Schema)} can be improved slightly and made more readable.

  • Constructor Summary

    Constructors
    Constructor
    Description
    NonCachingDatumReader()
     
    NonCachingDatumReader(org.apache.avro.Schema schema)
     

  • Method Summary

    Modifier and Type
    Method
    Description
    protected Class
    findStringClass(org.apache.avro.Schema schema)
     
    protected Object
    readString(Object old, org.apache.avro.Schema expected, org.apache.avro.io.Decoder in)
     

    Methods inherited from class org.apache.avro.generic.GenericDatumReader

    addToArray, addToMap, convert, createBytes, createEnum, createFixed, createFixed, createString, getData, getExpected, getResolver, getSchema, newArray, newInstanceFromString, newMap, newRecord, peekArray, read, read, readArray, readBytes, readBytes, readEnum, readField, readFixed, readInt, readMap, readMapKey, readRecord, readString, readWithConversion, readWithoutConversion, setExpected, setSchema, skip

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • NonCachingDatumReader

      public NonCachingDatumReader()

    • NonCachingDatumReader

      public NonCachingDatumReader(org.apache.avro.Schema schema)

  • Method Details

    • readString

      protected Object readString(Object old, org.apache.avro.Schema expected, org.apache.avro.io.Decoder in) throws IOException
      Overrides:
      readString in class org.apache.avro.generic.GenericDatumReader<T>
      Throws:
      IOException

    • findStringClass

      protected Class findStringClass(org.apache.avro.Schema schema)
      Overrides:
      findStringClass in class org.apache.avro.generic.GenericDatumReader<T>