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HttpEntity.javaAPI DocAndroid 1.5 API8188Wed May 06 22:41:10 BST 2009org.apache.http

HttpEntity

public interface HttpEntity
An entity that can be sent or received with an HTTP message. Entities can be found in some {@link HttpEntityEnclosingRequest requests} and in {@link HttpResponse responses}, where they are optional.

In some places, the JavaDoc distinguishes three kinds of entities, depending on where their {@link #getContent 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 {@link HttpConnection connection}. {@link #isStreaming Streamed} entities are generally not {@link #isRepeatable 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 {@link #isRepeatable 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.
author
Oleg Kalnichevski
version
$Revision: 645824 $
since
4.0

Fields Summary
Constructors Summary
Methods Summary
public voidconsumeContent()
TODO: The name of this method is misnomer. It will be renamed to #finish() in the next major release.
This method is called to indicate that the content of this entity is no longer required. All entity implementations are expected to release all allocated resources as a result of this method invocation. Content streaming entities are also expected to dispose of the remaining content, if any. Wrapping entities should delegate this call to the wrapped entity.
This method is of particular importance for entities being received from a {@link HttpConnection connection}. The entity needs to be consumed completely in order to re-use the connection with keep-alive.

throws
IOException if an I/O error occurs. This indicates that connection keep-alive is not possible.

public java.io.InputStreamgetContent()
Creates a new InputStream object of the entity. It is a programming error to return the same InputStream object more than once. Entities that are not {@link #isRepeatable repeatable} will throw an exception if this method is called multiple times.

return
a new input stream that returns the entity data.
throws
IOException if the stream could not be created
throws
IllegalStateException if this entity is not repeatable and the stream has already been obtained previously

public org.apache.http.HeadergetContentEncoding()
Obtains the Content-Encoding header, if known. This is the header that should be used when sending the entity, or the one that was received with the entity. Wrapping entities that modify the content encoding should adjust this header accordingly.

return
the Content-Encoding header for this entity, or null if the content encoding is unknown

public longgetContentLength()
Tells the length of the content, if known.

return
the number of bytes of the content, or a negative number if unknown. If the content length is known but exceeds {@link java.lang.Long#MAX_VALUE Long.MAX_VALUE}, a negative number is returned.

public org.apache.http.HeadergetContentType()
Obtains the Content-Type header, if known. This is the header that should be used when sending the entity, or the one that was received with the entity. It can include a charset attribute.

return
the Content-Type header for this entity, or null if the content type is unknown

public booleanisChunked()
Tells about chunked encoding for this entity. The primary purpose of this method is to indicate whether chunked encoding should be used when the entity is sent. For entities that are received, it can also indicate whether the entity was received with chunked encoding.
The behavior of wrapping entities is implementation dependent, but should respect the primary purpose.

return
true if chunked encoding is preferred for this entity, or false if it is not

public booleanisRepeatable()
Tells if the entity is capable to produce 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.

return
true if the entity is repeatable, false otherwise.

public booleanisStreaming()
Tells whether this entity depends on an underlying stream. Streamed entities should return true until the content has been consumed, false afterwards. Self-contained entities should return false. Wrapping entities should delegate this call to the wrapped entity.
The content of a streamed entity is consumed when the stream returned by {@link #getContent getContent} has been read to EOF, or after {@link #consumeContent consumeContent} has been called. If a streamed entity can not detect whether the stream has been read to EOF, it should return true until {@link #consumeContent consumeContent} is called.

return
true if the entity content is streamed and not yet consumed, false otherwise

public voidwriteTo(java.io.OutputStream outstream)
Writes the entity content to the output stream.

param
outstream the output stream to write entity content to
throws
IOException if an I/O error occurs