Interface Response
- All Superinterfaces:
ResponseHeader
,StatusLine
- All Known Implementing Classes:
ResponseWrapper
OutputStream
can be acquired via this interface
which can be used to write the response body. A buffer size can be
specified when acquiring the output stream which allows data to
be buffered until it over flows or is flushed explicitly. This
buffering allows a partially written response body to be reset.
This should never allow the message body be sent if it should not be sent with the headers as of RFC 2616 rules for the presence of a message body. A message body must not be included with a HEAD request or with a 304 or a 204 response. A proper implementation of this will prevent a message body being sent if the response is to a HEAD request of if there is a 304 or 204 response code.
It is important to note that the Response
controls
the processing of the HTTP pipeline. The next HTTP request is
not processed until the response has been sent. To ensure that
the response is sent the close
method of the response
or the output stream should be used. This will notify the server
to dispatch the next request in the pipeline for processing.
- Author:
- Niall Gallagher
-
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
This is used to close the connection and commit the request.void
commit()
This is used to write the headers that where given to theResponse
.Used to write a message body with theResponse
.getByteChannel
(int size) Used to write a message body with theResponse
.Used to write a message body with theResponse
.getOutputStream
(int size) Used to write a message body with theResponse
.This method is provided for convenience so that the HTTP content can be written using theprint
methods provided by thePrintStream
.getPrintStream
(int size) This method is provided for convenience so that the HTTP content can be written using theprint
methods provided by thePrintStream
.boolean
This can be used to determine whether theResponse
has been committed.void
reset()
This can be used to determine whether theResponse
has been committed.void
setContentLength
(int length) This should be used when the size of the message body is known.Methods inherited from interface org.simpleframework.http.ResponseHeader
add, add, addDate, contains, getContentLength, getContentType, getCookie, getCookies, getDate, getInteger, getNames, getTransferEncoding, getValue, getValues, remove, set, set, setCookie, setCookie, setDate
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Method Details
-
setContentLength
void setContentLength(int length) This should be used when the size of the message body is known. This ensures that Persistent HTTP (PHTTP) connections can be maintained for both HTTP/1.0 and HTTP/1.1 clients. If the length of the output is not known HTTP/1.0 clients will require a connection close, which reduces performance (see RFC 2616).This removes any previous Content-Length headers from the message header. This will then set the appropriate Content-Length header with the correct length. If a the Connection header is set with the close token then the semantics of the connection are such that the server will close it once the output stream or request is closed.
- Parameters:
length
- this is the length of the HTTP message body
-
getOutputStream
Used to write a message body with theResponse
. The semantics of thisOutputStream
will be determined by the HTTP version of the client, and whether or not the content length has been set, through thesetContentLength
method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.- Returns:
- an output stream object with the specified semantics
- Throws:
IOException
-
getOutputStream
Used to write a message body with theResponse
. The semantics of thisOutputStream
will be determined by the HTTP version of the client, and whether or not the content length has been set, through thesetContentLength
method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.This will ensure that there is buffering done so that the output can be reset using the
reset
method. This will enable the specified number of bytes to be written without committing the response. This specified size is the minimum size that the response buffer must be.- Returns:
- an output stream object with the specified semantics
- Throws:
IOException
-
getPrintStream
This method is provided for convenience so that the HTTP content can be written using theprint
methods provided by thePrintStream
. This will basically wrap thegetOutputStream
with a buffer size of zero.The retrieved
PrintStream
uses the charset used to describe the content, with the Content-Type header. This will check the charset parameter of the contents MIME type. So if the Content-Type wastext/plain; charset=UTF-8
the resultingPrintStream
would encode the written data using the UTF-8 encoding scheme. Care must be taken to ensure that bytes written to the stream are correctly encoded.Implementations of the
Response
must guarantee that this can be invoked repeatedly without effecting any issuedOutputStream
orPrintStream
object.- Returns:
- a print stream that provides convenience writing
- Throws:
IOException
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getPrintStream
This method is provided for convenience so that the HTTP content can be written using theprint
methods provided by thePrintStream
. This will basically wrap thegetOutputStream
with a specified buffer size.The retrieved
PrintStream
uses the charset used to describe the content, with the Content-Type header. This will check the charset parameter of the contents MIME type. So if the Content-Type wastext/plain; charset=UTF-8
the resultingPrintStream
would encode the written data using the UTF-8 encoding scheme. Care must be taken to ensure that bytes written to the stream are correctly encoded.Implementations of the
Response
must guarantee that this can be invoked repeatedly without effecting any issuedOutputStream
orPrintStream
object.- Parameters:
size
- the minimum size that the response buffer must be- Returns:
- a print stream that provides convenience writing
- Throws:
IOException
-
getByteChannel
Used to write a message body with theResponse
. The semantics of thisWritableByteChannel
are determined by the HTTP version of the client, and whether or not the content length has been set, through thesetContentLength
method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.- Returns:
- a writable byte channel used to write the message body
- Throws:
IOException
-
getByteChannel
Used to write a message body with theResponse
. The semantics of thisWritableByteChannel
are determined by the HTTP version of the client, and whether or not the content length has been set, through thesetContentLength
method. If the length of the output is not known then the output is chunked for HTTP/1.1 clients and closed for HTTP/1.0 clients.This will ensure that there is buffering done so that the output can be reset using the
reset
method. This will enable the specified number of bytes to be written without committing the response. This specified size is the minimum size that the response buffer must be.- Parameters:
size
- the minimum size that the response buffer must be- Returns:
- a writable byte channel used to write the message body
- Throws:
IOException
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isCommitted
boolean isCommitted()This can be used to determine whether theResponse
has been committed. This is true if theResponse
was committed, either due to an explicit invocation of thecommit
method or due to the writing of content. If theResponse
has committed thereset
method will not work in resetting content already written.- Returns:
- true if the response headers have been committed
-
commit
This is used to write the headers that where given to theResponse
. Any further attempts to give headers to theResponse
will be futile as only the headers that were given at the time of the first commit will be used in the message header.This also performs some final checks on the headers submitted. This is done to determine the optimal performance of the output. If no specific Connection header has been specified this will set the connection so that HTTP/1.0 closes by default.
- Throws:
IOException
- thrown if there was a problem writing
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reset
This can be used to determine whether theResponse
has been committed. This is true if theResponse
was committed, either due to an explicit invocation of thecommit
method or due to the writing of content. If theResponse
has committed thereset
method will not work in resetting content already written.- Throws:
IOException
- thrown if there is a problem resetting
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close
This is used to close the connection and commit the request. This provides the same semantics as closing the output stream and ensures that the HTTP response is committed. This will throw an exception if the response can not be committed.- Throws:
IOException
- thrown if there is a problem writing
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