Package com.linecorp.armeria.common.stream

Interface StreamDecoder<I,O>

Type Parameters:
I - the input type to decode
O - the output type of being decoded
All Known Subinterfaces:
HttpDecoder<T>
All Known Implementing Classes:
ArmeriaMessageDeframer
@UnstableApi public interface StreamDecoder<I,O>
Decodes a stream of data to N objects.

Follow the below steps to decode data using StreamDecoder.

  1. Implement your decoding logic in StreamDecoder. 
    
       > class FixedLengthDecoder implements StreamDecoder<String> {
       >     private final int length;
       >
       >     FixedLengthDecoder(int length) {
       >         this.length = length;
       >     }
       >
       >     @Override
       >     public ByteBuf toByteBuf(HttpData in) {
       >         return in.byteBuf();
       >     }
       >
       >     @Override
       >     public void process(StreamDecoderInput in, StreamDecoderOutput<String> out) {
       >         int remaining = in.readableBytes();
       >         if (remaining < length) {
       >             // The input is not enough to process. Waiting for more data.
       >             return;
       >         }
       >
       >         do {
       >             // Read data from 'StreamDecoderInput' and
       >             // write the processed result to 'StreamDecoderOutput'.
       >             ByteBuf buf = in.readBytes(length);
       >             out.add(buf.toString(StandardCharsets.UTF_8));
       >             // Should release the returned 'ByteBuf'
       >             buf.release();
       >             remaining -= length;
       >         } while (remaining >= length);
       >     }
       > }
  2. Create a decoded StreamMessage using StreamMessage.decode(StreamDecoder) with the StreamDecoder instance. 
    
       FixedLengthDecoder decoder = new FixedLengthDecoder(11);
       StreamMessage<HttpData> stream = ...;
       StreamMessage<String> decoded = stream.decode(decoder);
  3. Subscribe to the Publisher of the decoded data and connect to your business logic. 
    
       import reactor.core.publisher.Flux;
       Flux.from(decoded).map(...); // Consume and manipulate the decoded data.