ObjectStream (Apache OpenNLP Tools 2.5.9 API)
Description: declaration: package: opennlp.tools.util, interface: ObjectStream

# Interface ObjectStream<T>

All Superinterfaces:
  `AutoCloseable`

All Known Subinterfaces:
  `SequenceStream<S>`

All Known Implementing Classes:
  `AbstractEventStream, AbstractObjectStream, AbstractParserEventStream, AbstractToSentenceSampleStream, ADChunkSampleStream, ADNameSampleStream, ADPOSSampleStream, ADSentenceSampleStream, ADSentenceStream, BioNLP2004NameSampleStream, BratAnnotationStream, BratDocumentStream, BratNameSampleStream, ChecksumEventStream, ChunkerEventStream, ChunkSampleSequenceStream, ChunkSampleStream, ChunkSampleStream, CollectionObjectStream, Conll02NameSampleStream, Conll03NameSampleStream, ConlluLemmaSampleStream, ConlluPOSSampleStream, ConlluSentenceSampleStream, ConlluStream, ConlluTokenSampleStream, ConllXPOSSampleStream, ConstitParseSampleStream, CrossValidationPartitioner.TrainingSampleStream, DetokenizeSentenceSampleStream, DirectorySampleStream, DocumentCategorizerEventStream, DocumentSampleStream, DocumentToLineStream, EmptyLinePreprocessorStream, EvalitaNameSampleStream, EventTraceStream, FileEventStream, FileToByteArraySampleStream, FileToStringSampleStream, FilterObjectStream, LanguageDetectorEventStream, LanguageDetectorSampleStream, LeipzigLanguageSampleStream, LemmaSampleEventStream, LemmaSampleSequenceStream, LemmaSampleStream, MascDocumentStream, MascNamedEntitySampleStream, MascPOSSampleStream, MascSentenceSampleStream, MascTokenSampleStream, MosesSentenceSampleStream, MucNameSampleStream, NameFinderCensus90NameStream, NameFinderEventStream, NameSampleCountersStream, NameSampleDataStream, NameSampleSequenceStream, NameSampleTypeFilter, NameToSentenceSampleStream, NameToTokenSampleStream, NKJPSentenceSampleStream, OntoNotesNameSampleStream, OntoNotesParseSampleStream, ParagraphStream, ParserEventStream, ParserEventStream, ParseSampleStream, ParseToPOSSampleStream, PlainTextByLineStream, POSSampleEventStream, POSSampleSequenceStream, PosSampleStream, POSToSentenceSampleStream, POSToTokenSampleStream, RealBasicEventStream, RealValueFileEventStream, SDEventStream, SegmenterObjectStream, SentenceSampleStream, SequenceStreamEventStream, TokenizerStream, TokenSampleStream, TokSpanEventStream, TwentyNewsgroupSampleStream, WhitespaceTokenStream, WordTagSampleStream`

public interface ObjectStream<T> extends AutoCloseable
Reads `objects` from a stream.

Design Decision:
This interface provides a means for iterating over the objects in a stream, it does not implement `Iterator` or `Iterable` because:

- `Iterator.next()` and `Iterator.hasNext()` are declared as throwing no checked exceptions. Thus the `IOException`s thrown by `read()` would have to be wrapped in `RuntimeException`s, and the compiler would be unable to force users of this code to catch such exceptions.
- Implementing `Iterable` would mean either silently calling `reset()` to guarantee that all items were always seen on each iteration, or documenting that the Iterable only iterates over the remaining elements of the ObjectStream. In either case, users not reading the documentation carefully might run into unexpected behavior.

See Also:
  - `ObjectStreamException`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `default void`
  `close()`
  Closes the `ObjectStream` and releases all allocated resources.
  `T`
  `read()`
  Returns the next `T` object.
  `default void`
  `reset()`
  Repositions the stream at the beginning and the previously seen object sequence will be repeated exactly.

- ## Method Details

  - ### read

    T read() throws IOException
    Returns the next `T` object. Calling this method repeatedly until it returns `null` will return each object from the underlying source exactly once.
    Returns:
      The next object or `null` to signal that the stream is exhausted.
    Throws:
      `IOException` - Thrown if there is an error during reading.

  - ### reset

    default void reset() throws IOException
    Repositions the stream at the beginning and the previously seen object sequence will be repeated exactly. This method can be used to re-read the stream if multiple passes over the objects are required.

    The implementation of this method is optional.

    Throws:
      `IOException` - Thrown if there is an error during resetting the stream.
      `UnsupportedOperationException` - Thrown if the `reset()` is not supported. By default, this is the case.

  - ### close

    default void close() throws IOException
    Closes the `ObjectStream` and releases all allocated resources. After close was called, it's not allowed to call `read()` or `reset()`.
    Specified by:
      `close` in interface `AutoCloseable`
    Throws:
      `IOException` - Thrown if there is an error during closing the stream.