kafka.serializer.Decoder.scala Maven / Gradle / Ivy
/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package kafka.serializer
import java.nio.ByteBuffer
import kafka.utils.VerifiableProperties
/**
* A decoder is a method of turning byte arrays into objects.
* An implementation is required to provide a constructor that
* takes a VerifiableProperties instance.
*/
trait Decoder[T] {
def fromBytes(bytes: Array[Byte]): T
}
/**
* The default implementation does nothing, just returns the same byte array it takes in.
*/
class DefaultDecoder(props: VerifiableProperties = null) extends Decoder[Array[Byte]] {
def fromBytes(bytes: Array[Byte]): Array[Byte] = bytes
}
/**
* The string decoder translates bytes into strings. It uses UTF8 by default but takes
* an optional property serializer.encoding to control this.
*/
class StringDecoder(props: VerifiableProperties = null) extends Decoder[String] {
val encoding =
if(props == null)
"UTF8"
else
props.getString("serializer.encoding", "UTF8")
def fromBytes(bytes: Array[Byte]): String = {
new String(bytes, encoding)
}
}
/**
* The long decoder translates bytes into longs.
*/
class LongDecoder(props: VerifiableProperties = null) extends Decoder[Long] {
def fromBytes(bytes: Array[Byte]): Long = {
ByteBuffer.wrap(bytes).getLong
}
}
/**
* The integer decoder translates bytes into integers.
*/
class IntegerDecoder(props: VerifiableProperties = null) extends Decoder[Integer] {
def fromBytes(bytes: Array[Byte]): Integer = {
ByteBuffer.wrap(bytes).getInt()
}
}