org.apache.shindig.gadgets.servlet

Class ETaggingHttpResponse

java.lang.Object

javax.servlet.ServletResponseWrapper

javax.servlet.http.HttpServletResponseWrapper

org.apache.shindig.gadgets.servlet.ETaggingHttpResponse

All Implemented Interfaces:

javax.servlet.http.HttpServletResponse, javax.servlet.ServletResponse

public class ETaggingHttpResponse
extends javax.servlet.http.HttpServletResponseWrapper

A class for generating and managing ETags for improved caching. Objects of this class have two modes: batching mode and streaming mode. In batching mode, the response body is stored in a buffer and, at the end, its ETag is calculated and everything is written to the output at once. In streaming mode, however, the response body is output as it's received from the servlet, and no ETag is calculated.

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	batching
protected javax.servlet.ServletOutputStream	originalStream
protected javax.servlet.http.HttpServletRequest	request
static String	REQUEST_HEADER
static String	RESPONSE_HEADER
protected org.apache.shindig.gadgets.servlet.ETaggingHttpResponse.BufferServletOutputStream	stream
protected PrintWriter	writer

Fields inherited from interface javax.servlet.http.HttpServletResponse

SC_ACCEPTED, SC_BAD_GATEWAY, SC_BAD_REQUEST, SC_CONFLICT, SC_CONTINUE, SC_CREATED, SC_EXPECTATION_FAILED, SC_FORBIDDEN, SC_FOUND, SC_GATEWAY_TIMEOUT, SC_GONE, SC_HTTP_VERSION_NOT_SUPPORTED, SC_INTERNAL_SERVER_ERROR, SC_LENGTH_REQUIRED, SC_METHOD_NOT_ALLOWED, SC_MOVED_PERMANENTLY, SC_MOVED_TEMPORARILY, SC_MULTIPLE_CHOICES, SC_NO_CONTENT, SC_NON_AUTHORITATIVE_INFORMATION, SC_NOT_ACCEPTABLE, SC_NOT_FOUND, SC_NOT_IMPLEMENTED, SC_NOT_MODIFIED, SC_OK, SC_PARTIAL_CONTENT, SC_PAYMENT_REQUIRED, SC_PRECONDITION_FAILED, SC_PROXY_AUTHENTICATION_REQUIRED, SC_REQUEST_ENTITY_TOO_LARGE, SC_REQUEST_TIMEOUT, SC_REQUEST_URI_TOO_LONG, SC_REQUESTED_RANGE_NOT_SATISFIABLE, SC_RESET_CONTENT, SC_SEE_OTHER, SC_SERVICE_UNAVAILABLE, SC_SWITCHING_PROTOCOLS, SC_TEMPORARY_REDIRECT, SC_UNAUTHORIZED, SC_UNSUPPORTED_MEDIA_TYPE, SC_USE_PROXY

Constructor Summary

Constructors

Constructor and Description
ETaggingHttpResponse(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	emitETagMatchedResult()
protected void	emitFullResponseBody(byte[] bytes)
protected boolean	etagMatches(String etag)
void	flushBuffer() The response object is also switched to streaming mode.
javax.servlet.ServletOutputStream	getOutputStream()
PrintWriter	getWriter()
void	reset() The response object is switched to batching mode if the response has not been committed yet.
void	resetBuffer() The response object is switched to batching mode if the response has not been committed yet.
void	startStreaming() Switches this response object to streaming mode.
protected void	writeToOutput() Outputs the response body.

Methods inherited from class javax.servlet.http.HttpServletResponseWrapper

addCookie, addDateHeader, addHeader, addIntHeader, containsHeader, encodeRedirectUrl, encodeRedirectURL, encodeUrl, encodeURL, sendError, sendError, sendRedirect, setDateHeader, setHeader, setIntHeader, setStatus, setStatus

Methods inherited from class javax.servlet.ServletResponseWrapper

getBufferSize, getCharacterEncoding, getContentType, getLocale, getResponse, isCommitted, setBufferSize, setCharacterEncoding, setContentLength, setContentType, setLocale, setResponse

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface javax.servlet.ServletResponse

getBufferSize, getCharacterEncoding, getContentType, getLocale, isCommitted, setBufferSize, setCharacterEncoding, setContentLength, setContentType, setLocale

Field Detail

RESPONSE_HEADER

public static final String RESPONSE_HEADER

See Also:

Constant Field Values

REQUEST_HEADER

public static final String REQUEST_HEADER

See Also:

Constant Field Values

request

protected final javax.servlet.http.HttpServletRequest request

stream

protected final org.apache.shindig.gadgets.servlet.ETaggingHttpResponse.BufferServletOutputStream stream

originalStream

protected javax.servlet.ServletOutputStream originalStream

writer

protected PrintWriter writer

batching

protected boolean batching

Constructor Detail

ETaggingHttpResponse

public ETaggingHttpResponse(javax.servlet.http.HttpServletRequest request,
                    javax.servlet.http.HttpServletResponse response)

Method Detail

getOutputStream

public javax.servlet.ServletOutputStream getOutputStream()
                                                  throws IOException

Specified by:

getOutputStream in interface javax.servlet.ServletResponse

Overrides:

getOutputStream in class javax.servlet.ServletResponseWrapper

Throws:

IOException

getWriter

public PrintWriter getWriter()
                      throws IOException

Specified by:

getWriter in interface javax.servlet.ServletResponse

Overrides:

getWriter in class javax.servlet.ServletResponseWrapper

Throws:

IOException

flushBuffer

public void flushBuffer()
                 throws IOException

The response object is also switched to streaming mode.

Specified by:

flushBuffer in interface javax.servlet.ServletResponse

Overrides:

flushBuffer in class javax.servlet.ServletResponseWrapper

Throws:

IOException

reset

public void reset()

The response object is switched to batching mode if the response has not been committed yet.

Specified by:

reset in interface javax.servlet.ServletResponse

Overrides:

reset in class javax.servlet.ServletResponseWrapper

resetBuffer

public void resetBuffer()

The response object is switched to batching mode if the response has not been committed yet.

Specified by:

resetBuffer in interface javax.servlet.ServletResponse

Overrides:

resetBuffer in class javax.servlet.ServletResponseWrapper

startStreaming

public void startStreaming()
                    throws IOException

Switches this response object to streaming mode. The current buffer is written to the output, as are any subsequent writes.

Throws:

IOException - If flushing the buffer produced an exception.

writeToOutput

protected void writeToOutput()
                      throws IOException

Outputs the response body. In batching mode, it outputs the full contents of the buffer with its corresponding ETag, or a NOT_MODIFIED response if the ETag matches the request's "If-None-Match" header. In streaming mode, output is only generated if the buffer is not empty; in that case, the buffer is flushed to the output.

Throws:

IOException - If there was a problem writing to the output.

etagMatches

protected boolean etagMatches(String etag)

emitETagMatchedResult

protected void emitETagMatchedResult()

emitFullResponseBody

protected void emitFullResponseBody(byte[] bytes)
                             throws IOException

Throws:

IOException