Package org.apache.hc.core5.http

Interface HttpEntity

All Superinterfaces:
AutoCloseable, Closeable, EntityDetails
All Known Implementing Classes:
AbstractHttpEntity, BasicHttpEntity, BufferedHttpEntity, ByteArrayEntity, ByteBufferEntity, EntityTemplate, FileEntity, HttpEntityWrapper, IncomingHttpEntity, InputStreamEntity, NullEntity, PathEntity, SerializableEntity, StringEntity
public interface HttpEntity extends EntityDetails, Closeable
An entity that can be sent or received with an HTTP message.

There are three distinct types of entities in HttpCore, depending on where their content originates:

  • streamed: The content is received from a stream, or generated on the fly. In particular, this category includes entities being received from a connection. Streamed entities are generally not repeatable.
  • self-contained: The content is in memory or obtained by means that are independent from a connection or other entity. Self-contained entities are generally repeatable.
  • wrapping: The content is obtained from another entity.

This distinction is important for connection management with incoming entities. For entities that are created by an application and only sent using the HTTP components framework, the difference between streamed and self-contained is of little importance. In that case, it is suggested to consider non-repeatable entities as streamed, and those that are repeatable (without a huge effort) as self-contained.

Since:
4.0

  • Method Details

    • isRepeatable

      boolean isRepeatable()
      Tells if the entity is capable of producing its data more than once. A repeatable entity's getContent() and writeTo(OutputStream) methods can be called more than once whereas a non-repeatable entity's can not.
      Returns:
      true if the entity is repeatable, false otherwise.

    • getContent

      InputStream getContent() throws IOException, UnsupportedOperationException
      Returns a content stream of the entity. Repeatable entities are expected to create a new instance of InputStream for each invocation of this method and therefore can be consumed multiple times. Entities that are not repeatable are expected to return the same InputStream instance and therefore may not be consumed more than once.

      If this entity belongs to an incoming HTTP message, calling InputStream.close() on the returned InputStream will try to consume the complete entity content to keep the connection alive. In cases where this is undesired, e.g. when only a small part of the content is relevant and consuming the complete entity content would be too inefficient, only the HTTP message from which this entity was obtained should be closed (if supported).

      IMPORTANT: Please note all entity implementations must ensure that all allocated resources are properly deallocated after the InputStream.close() method is invoked.

      Returns:
      content stream of the entity.
      Throws:
      IOException - if the stream could not be created
      UnsupportedOperationException - if entity content cannot be represented as InputStream.
      See Also:

    • writeTo

      void writeTo(OutputStream outStream) throws IOException
      Writes the entity content out to the output stream.

      IMPORTANT: Please note all entity implementations must ensure that all allocated resources are properly deallocated when this method returns.

      Parameters:
      outStream - the output stream to write entity content to
      Throws:
      IOException - if an I/O error occurs

    • isStreaming

      boolean isStreaming()
      Tells whether this entity depends on an underlying stream. Streamed entities that read data directly from the socket should return true. Self-contained entities should return false. Wrapping entities should delegate this call to the wrapped entity.
      Returns:
      true if the entity content is streamed, false otherwise

    • getTrailers

      Supplier<List<? extends Header>> getTrailers()
      Returns supplier of message trailers - headers sent after message body. May return null if trailers are not available.
      Since:
      5.0