org.jboss.resteasy.core

Class ResteasyHttpServletResponseWrapper

java.lang.Object

javax.servlet.ServletResponseWrapper

org.jboss.resteasy.core.ResteasyHttpServletResponseWrapper

All Implemented Interfaces:

HttpServletResponse, ServletResponse

public class ResteasyHttpServletResponseWrapper
extends ServletResponseWrapper
implements HttpServletResponse

ResteasyHttpServletResponseWrapper is introduced to support the use of RequestDispatcher.forward() and RequestDispatcher.include(), which need to be able to retrieve the orginal HttpServletResponse.

Version:

$Revision: 1.1 $ Copyright Apr 18, 2014

Author:

Ron Sigal

Field Summary

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
ResteasyHttpServletResponseWrapper(HttpServletResponse response, HttpServletResponse proxy)

Method Summary

Modifier and Type	Method and Description
void	addCookie(Cookie cookie) Adds the specified cookie to the response.
void	addDateHeader(String name, long date) Adds a response header with the given name and date-value.
void	addHeader(String name, String value) Adds a response header with the given name and value.
void	addIntHeader(String name, int value) Adds a response header with the given name and integer value.
boolean	containsHeader(String name) Returns a boolean indicating whether the named response header has already been set.
String	encodeRedirectUrl(String url) Deprecated. As of version 2.1, use encodeRedirectURL(String url) instead
String	encodeRedirectURL(String url) Encodes the specified URL for use in the sendRedirect method or, if encoding is not needed, returns the URL unchanged.
String	encodeUrl(String url) Deprecated. As of version 2.1, use encodeURL(String url) instead
String	encodeURL(String url) Encodes the specified URL by including the session ID, or, if encoding is not needed, returns the URL unchanged.
void	flushBuffer() The default behavior of this method is to call flushBuffer() on the wrapped response object.
int	getBufferSize() The default behavior of this method is to return getBufferSize() on the wrapped response object.
String	getCharacterEncoding() The default behavior of this method is to return getCharacterEncoding() on the wrapped response object.
String	getContentType() The default behavior of this method is to return getContentType() on the wrapped response object.
String	getHeader(String name) Gets the value of the response header with the given name.
Collection<String>	getHeaderNames() Gets the names of the headers of this response.
Collection<String>	getHeaders(String name) Gets the values of the response header with the given name.
HttpServletResponse	getHttpServletResponse()
Locale	getLocale() The default behavior of this method is to return getLocale() on the wrapped response object.
ServletOutputStream	getOutputStream() The default behavior of this method is to return getOutputStream() on the wrapped response object.
ServletResponse	getResponse() Return the wrapped ServletResponse object.
int	getStatus() Gets the current status code of this response.
PrintWriter	getWriter() The default behavior of this method is to return getWriter() on the wrapped response object.
boolean	isCommitted() The default behavior of this method is to return isCommitted() on the wrapped response object.
void	reset() The default behavior of this method is to call reset() on the wrapped response object.
void	resetBuffer() The default behavior of this method is to call resetBuffer() on the wrapped response object.
void	sendError(int sc) Sends an error response to the client using the specified status code and clears the buffer.
void	sendError(int sc, String msg) Sends an error response to the client using the specified status and clears the buffer.
void	sendRedirect(String location) Sends a temporary redirect response to the client using the specified redirect location URL and clears the buffer.
void	setBufferSize(int size) The default behavior of this method is to call setBufferSize(int size) on the wrapped response object.
void	setCharacterEncoding(String charset) The default behavior of this method is to call setCharacterEncoding(String charset) on the wrapped response object.
void	setContentLength(int len) The default behavior of this method is to call setContentLength(int len) on the wrapped response object.
void	setContentType(String type) The default behavior of this method is to call setContentType(String type) on the wrapped response object.
void	setDateHeader(String name, long date) Sets a response header with the given name and date-value.
void	setHeader(String name, String value) Sets a response header with the given name and value.
void	setIntHeader(String name, int value) Sets a response header with the given name and integer value.
void	setLocale(Locale loc) The default behavior of this method is to call setLocale(Locale loc) on the wrapped response object.
void	setStatus(int sc) Sets the status code for this response.
void	setStatus(int sc, String sm) Deprecated. As of version 2.1, due to ambiguous meaning of the message parameter. To set a status code use setStatus(int), to send an error with a description use sendError(int, String). Sets the status code and message for this response.

Methods inherited from class javax.servlet.ServletResponseWrapper

isWrapperFor, isWrapperFor, setContentLengthLong, 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

setContentLengthLong

Constructor Detail

ResteasyHttpServletResponseWrapper

public ResteasyHttpServletResponseWrapper(HttpServletResponse response,
                                          HttpServletResponse proxy)

Method Detail

getHttpServletResponse

public HttpServletResponse getHttpServletResponse()

getResponse

public ServletResponse getResponse()

Description copied from class: ServletResponseWrapper

Return the wrapped ServletResponse object.

Overrides:

getResponse in class ServletResponseWrapper

getCharacterEncoding

public String getCharacterEncoding()

Description copied from class: ServletResponseWrapper

The default behavior of this method is to return getCharacterEncoding() on the wrapped response object.

Specified by:

getCharacterEncoding in interface ServletResponse

Overrides:

getCharacterEncoding in class ServletResponseWrapper

Returns:

a String specifying the name of the character encoding, for example, UTF-8

getContentType

public String getContentType()

Description copied from class: ServletResponseWrapper

The default behavior of this method is to return getContentType() on the wrapped response object.

Specified by:

getContentType in interface ServletResponse

Overrides:

getContentType in class ServletResponseWrapper

Returns:

a String specifying the content type, for example, text/html; charset=UTF-8, or null

getOutputStream

public ServletOutputStream getOutputStream()
                                    throws IOException

Description copied from class: ServletResponseWrapper

The default behavior of this method is to return getOutputStream() on the wrapped response object.

Specified by:

getOutputStream in interface ServletResponse

Overrides:

getOutputStream in class ServletResponseWrapper

Returns:

a ServletOutputStream for writing binary data

Throws:

IOException - if an input or output exception occurred

See Also:

ServletResponse.getWriter(), ServletResponse.reset()

getWriter

public PrintWriter getWriter()
                      throws IOException

Description copied from class: ServletResponseWrapper

The default behavior of this method is to return getWriter() on the wrapped response object.

Specified by:

getWriter in interface ServletResponse

Overrides:

getWriter in class ServletResponseWrapper

Returns:

a PrintWriter object that can return character data to the client

Throws:

UnsupportedEncodingException - if the character encoding returned by getCharacterEncoding cannot be used

IOException - if an input or output exception occurred

See Also:

ServletResponse.getOutputStream(), ServletResponse.setCharacterEncoding(java.lang.String), ServletResponse.reset()

setCharacterEncoding

public void setCharacterEncoding(String charset)

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call setCharacterEncoding(String charset) on the wrapped response object.

Specified by:

setCharacterEncoding in interface ServletResponse

Overrides:

setCharacterEncoding in class ServletResponseWrapper

Parameters:

charset - a String specifying only the character set defined by IANA Character Sets (http://www.iana.org/assignments/character-sets)

See Also:

ServletResponse.setContentType(java.lang.String), ServletResponse.setLocale(java.util.Locale)

setContentLength

public void setContentLength(int len)

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call setContentLength(int len) on the wrapped response object.

Specified by:

setContentLength in interface ServletResponse

Overrides:

setContentLength in class ServletResponseWrapper

Parameters:

len - an integer specifying the length of the content being returned to the client; sets the Content-Length header

setContentType

public void setContentType(String type)

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call setContentType(String type) on the wrapped response object.

Specified by:

setContentType in interface ServletResponse

Overrides:

setContentType in class ServletResponseWrapper

Parameters:

type - a String specifying the MIME type of the content

See Also:

ServletResponse.setLocale(java.util.Locale), ServletResponse.setCharacterEncoding(java.lang.String), ServletResponse.getOutputStream(), ServletResponse.getWriter()

setBufferSize

public void setBufferSize(int size)

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call setBufferSize(int size) on the wrapped response object.

Specified by:

setBufferSize in interface ServletResponse

Overrides:

setBufferSize in class ServletResponseWrapper

Parameters:

size - the preferred buffer size

See Also:

ServletResponse.getBufferSize(), ServletResponse.flushBuffer(), ServletResponse.isCommitted(), ServletResponse.reset()

getBufferSize

public int getBufferSize()

Description copied from class: ServletResponseWrapper

The default behavior of this method is to return getBufferSize() on the wrapped response object.

Specified by:

getBufferSize in interface ServletResponse

Overrides:

getBufferSize in class ServletResponseWrapper

Returns:

the actual buffer size used

See Also:

ServletResponse.setBufferSize(int), ServletResponse.flushBuffer(), ServletResponse.isCommitted(), ServletResponse.reset()

flushBuffer

public void flushBuffer()
                 throws IOException

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call flushBuffer() on the wrapped response object.

Specified by:

flushBuffer in interface ServletResponse

Overrides:

flushBuffer in class ServletResponseWrapper

Throws:

IOException

See Also:

ServletResponse.setBufferSize(int), ServletResponse.getBufferSize(), ServletResponse.isCommitted(), ServletResponse.reset()

resetBuffer

public void resetBuffer()

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call resetBuffer() on the wrapped response object.

Specified by:

resetBuffer in interface ServletResponse

Overrides:

resetBuffer in class ServletResponseWrapper

See Also:

ServletResponse.setBufferSize(int), ServletResponse.getBufferSize(), ServletResponse.isCommitted(), ServletResponse.reset()

isCommitted

public boolean isCommitted()

Description copied from class: ServletResponseWrapper

The default behavior of this method is to return isCommitted() on the wrapped response object.

Specified by:

isCommitted in interface ServletResponse

Overrides:

isCommitted in class ServletResponseWrapper

Returns:

a boolean indicating if the response has been committed

See Also:

ServletResponse.setBufferSize(int), ServletResponse.getBufferSize(), ServletResponse.flushBuffer(), ServletResponse.reset()

reset

public void reset()

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call reset() on the wrapped response object.

Specified by:

reset in interface ServletResponse

Overrides:

reset in class ServletResponseWrapper

See Also:

ServletResponse.setBufferSize(int), ServletResponse.getBufferSize(), ServletResponse.flushBuffer(), ServletResponse.isCommitted()

setLocale

public void setLocale(Locale loc)

Description copied from class: ServletResponseWrapper

The default behavior of this method is to call setLocale(Locale loc) on the wrapped response object.

Specified by:

setLocale in interface ServletResponse

Overrides:

setLocale in class ServletResponseWrapper

Parameters:

loc - the locale of the response

See Also:

ServletResponse.getLocale(), ServletResponse.setContentType(java.lang.String), ServletResponse.setCharacterEncoding(java.lang.String)

getLocale

public Locale getLocale()

Description copied from class: ServletResponseWrapper

The default behavior of this method is to return getLocale() on the wrapped response object.

Specified by:

getLocale in interface ServletResponse

Overrides:

getLocale in class ServletResponseWrapper

See Also:

ServletResponse.setLocale(java.util.Locale)

addCookie

public void addCookie(Cookie cookie)

Description copied from interface: HttpServletResponse

Adds the specified cookie to the response. This method can be called multiple times to set more than one cookie.

Specified by:

addCookie in interface HttpServletResponse

Parameters:

cookie - the Cookie to return to the client

containsHeader

public boolean containsHeader(String name)

Description copied from interface: HttpServletResponse

Returns a boolean indicating whether the named response header has already been set.

Specified by:

containsHeader in interface HttpServletResponse

Parameters:

name - the header name

Returns:

true if the named response header has already been set; false otherwise

encodeURL

public String encodeURL(String url)

Description copied from interface: HttpServletResponse

Encodes the specified URL by including the session ID, or, if encoding is not needed, returns the URL unchanged. The implementation of this method includes the logic to determine whether the session ID needs to be encoded in the URL. For example, if the browser supports cookies, or session tracking is turned off, URL encoding is unnecessary.

For robust session tracking, all URLs emitted by a servlet should be run through this method. Otherwise, URL rewriting cannot be used with browsers which do not support cookies.

If the URL is relative, it is always relative to the current HttpServletRequest.

Specified by:

encodeURL in interface HttpServletResponse

Parameters:

url - the url to be encoded.

Returns:

the encoded URL if encoding is needed; the unchanged URL otherwise.

encodeRedirectURL

public String encodeRedirectURL(String url)

Description copied from interface: HttpServletResponse

Encodes the specified URL for use in the sendRedirect method or, if encoding is not needed, returns the URL unchanged. The implementation of this method includes the logic to determine whether the session ID needs to be encoded in the URL. For example, if the browser supports cookies, or session tracking is turned off, URL encoding is unnecessary. Because the rules for making this determination can differ from those used to decide whether to encode a normal link, this method is separated from the encodeURL method.

All URLs sent to the HttpServletResponse.sendRedirect method should be run through this method. Otherwise, URL rewriting cannot be used with browsers which do not support cookies.

If the URL is relative, it is always relative to the current HttpServletRequest.

Specified by:

encodeRedirectURL in interface HttpServletResponse

Parameters:

url - the url to be encoded.

Returns:

the encoded URL if encoding is needed; the unchanged URL otherwise.

See Also:

HttpServletResponse.sendRedirect(java.lang.String), HttpServletResponse.encodeUrl(java.lang.String)

encodeUrl

public String encodeUrl(String url)

Deprecated. As of version 2.1, use encodeURL(String url) instead

Specified by:

encodeUrl in interface HttpServletResponse

Parameters:

url - the url to be encoded.

Returns:

the encoded URL if encoding is needed; the unchanged URL otherwise.

encodeRedirectUrl

public String encodeRedirectUrl(String url)

Deprecated. As of version 2.1, use encodeRedirectURL(String url) instead

Specified by:

encodeRedirectUrl in interface HttpServletResponse

Parameters:

url - the url to be encoded.

Returns:

the encoded URL if encoding is needed; the unchanged URL otherwise.

sendError

public void sendError(int sc,
                      String msg)
               throws IOException

Description copied from interface: HttpServletResponse

Sends an error response to the client using the specified status and clears the buffer. The server defaults to creating the response to look like an HTML-formatted server error page containing the specified message, setting the content type to "text/html". The server will preserve cookies and may clear or update any headers needed to serve the error page as a valid response. If an error-page declaration has been made for the web application corresponding to the status code passed in, it will be served back in preference to the suggested msg parameter and the msg parameter will be ignored.

If the response has already been committed, this method throws an IllegalStateException. After using this method, the response should be considered to be committed and should not be written to.

Specified by:

sendError in interface HttpServletResponse

Parameters:

sc - the error status code

msg - the descriptive message

Throws:

IOException - If an input or output exception occurs

sendError

public void sendError(int sc)
               throws IOException

Description copied from interface: HttpServletResponse

Sends an error response to the client using the specified status code and clears the buffer. The server will preserve cookies and may clear or update any headers needed to serve the error page as a valid response. If an error-page declaration has been made for the web application corresponding to the status code passed in, it will be served back the error page

If the response has already been committed, this method throws an IllegalStateException. After using this method, the response should be considered to be committed and should not be written to.

Specified by:

sendError in interface HttpServletResponse

Parameters:

sc - the error status code

Throws:

IOException - If an input or output exception occurs

sendRedirect

public void sendRedirect(String location)
                  throws IOException

Description copied from interface: HttpServletResponse

Sends a temporary redirect response to the client using the specified redirect location URL and clears the buffer. The buffer will be replaced with the data set by this method. Calling this method sets the status code to HttpServletResponse.SC_FOUND 302 (Found). This method can accept relative URLs;the servlet container must convert the relative URL to an absolute URL before sending the response to the client. If the location is relative without a leading '/' the container interprets it as relative to the current request URI. If the location is relative with a leading '/' the container interprets it as relative to the servlet container root. If the location is relative with two leading '/' the container interprets it as a network-path reference (see RFC 3986: Uniform Resource Identifier (URI): Generic Syntax, section 4.2 "Relative Reference").

If the response has already been committed, this method throws an IllegalStateException. After using this method, the response should be considered to be committed and should not be written to.

Specified by:

sendRedirect in interface HttpServletResponse

Parameters:

location - the redirect location URL

Throws:

IOException - If an input or output exception occurs

setDateHeader

public void setDateHeader(String name,
                          long date)

Description copied from interface: HttpServletResponse

Sets a response header with the given name and date-value. The date is specified in terms of milliseconds since the epoch. If the header had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.

Specified by:

setDateHeader in interface HttpServletResponse

Parameters:

name - the name of the header to set

date - the assigned date value

See Also:

HttpServletResponse.containsHeader(java.lang.String), HttpServletResponse.addDateHeader(java.lang.String, long)

addDateHeader

public void addDateHeader(String name,
                          long date)

Description copied from interface: HttpServletResponse

Adds a response header with the given name and date-value. The date is specified in terms of milliseconds since the epoch. This method allows response headers to have multiple values.

Specified by:

addDateHeader in interface HttpServletResponse

Parameters:

name - the name of the header to set

date - the additional date value

See Also:

HttpServletResponse.setDateHeader(java.lang.String, long)

setHeader

public void setHeader(String name,
                      String value)

Description copied from interface: HttpServletResponse

Sets a response header with the given name and value. If the header had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.

Specified by:

setHeader in interface HttpServletResponse

Parameters:

name - the name of the header

value - the header value If it contains octet string, it should be encoded according to RFC 2047 (http://www.ietf.org/rfc/rfc2047.txt)

See Also:

HttpServletResponse.containsHeader(java.lang.String), HttpServletResponse.addHeader(java.lang.String, java.lang.String)

addHeader

public void addHeader(String name,
                      String value)

Description copied from interface: HttpServletResponse

Adds a response header with the given name and value. This method allows response headers to have multiple values.

Specified by:

addHeader in interface HttpServletResponse

Parameters:

name - the name of the header

value - the additional header value If it contains octet string, it should be encoded according to RFC 2047 (http://www.ietf.org/rfc/rfc2047.txt)

See Also:

HttpServletResponse.setHeader(java.lang.String, java.lang.String)

setIntHeader

public void setIntHeader(String name,
                         int value)

Description copied from interface: HttpServletResponse

Sets a response header with the given name and integer value. If the header had already been set, the new value overwrites the previous one. The containsHeader method can be used to test for the presence of a header before setting its value.

Specified by:

setIntHeader in interface HttpServletResponse

Parameters:

name - the name of the header

value - the assigned integer value

See Also:

HttpServletResponse.containsHeader(java.lang.String), HttpServletResponse.addIntHeader(java.lang.String, int)

addIntHeader

public void addIntHeader(String name,
                         int value)

Description copied from interface: HttpServletResponse

Adds a response header with the given name and integer value. This method allows response headers to have multiple values.

Specified by:

addIntHeader in interface HttpServletResponse

Parameters:

name - the name of the header

value - the assigned integer value

See Also:

HttpServletResponse.setIntHeader(java.lang.String, int)

setStatus

public void setStatus(int sc)

Description copied from interface: HttpServletResponse

Sets the status code for this response.

This method is used to set the return status code when there is no error (for example, for the SC_OK or SC_MOVED_TEMPORARILY status codes).

If this method is used to set an error code, then the container's error page mechanism will not be triggered. If there is an error and the caller wishes to invoke an error page defined in the web application, then HttpServletResponse.sendError(int, java.lang.String) must be used instead.

This method preserves any cookies and other response headers.

Valid status codes are those in the 2XX, 3XX, 4XX, and 5XX ranges. Other status codes are treated as container specific.

Specified by:

setStatus in interface HttpServletResponse

Parameters:

sc - the status code

See Also:

HttpServletResponse.sendError(int, java.lang.String)

setStatus

public void setStatus(int sc,
                      String sm)

Deprecated. As of version 2.1, due to ambiguous meaning of the message parameter. To set a status code use setStatus(int), to send an error with a description use sendError(int, String). Sets the status code and message for this response.

Specified by:

setStatus in interface HttpServletResponse

Parameters:

sc - the status code

sm - the status message

getStatus

public int getStatus()

Description copied from interface: HttpServletResponse

Gets the current status code of this response.

Specified by:

getStatus in interface HttpServletResponse

Returns:

the current status code of this response

getHeader

public String getHeader(String name)

Description copied from interface: HttpServletResponse

Gets the value of the response header with the given name.

If a response header with the given name exists and contains multiple values, the value that was added first will be returned.

This method considers only response headers set or added via HttpServletResponse.setHeader(java.lang.String, java.lang.String), HttpServletResponse.addHeader(java.lang.String, java.lang.String), HttpServletResponse.setDateHeader(java.lang.String, long), HttpServletResponse.addDateHeader(java.lang.String, long), HttpServletResponse.setIntHeader(java.lang.String, int), or HttpServletResponse.addIntHeader(java.lang.String, int), respectively.

Specified by:

getHeader in interface HttpServletResponse

Parameters:

name - the name of the response header whose value to return

Returns:

the value of the response header with the given name, or null if no header with the given name has been set on this response

getHeaders

public Collection<String> getHeaders(String name)

Description copied from interface: HttpServletResponse

Gets the values of the response header with the given name.

This method considers only response headers set or added via HttpServletResponse.setHeader(java.lang.String, java.lang.String), HttpServletResponse.addHeader(java.lang.String, java.lang.String), HttpServletResponse.setDateHeader(java.lang.String, long), HttpServletResponse.addDateHeader(java.lang.String, long), HttpServletResponse.setIntHeader(java.lang.String, int), or HttpServletResponse.addIntHeader(java.lang.String, int), respectively.

Any changes to the returned Collection must not affect this HttpServletResponse.

Specified by:

getHeaders in interface HttpServletResponse

Parameters:

name - the name of the response header whose values to return

Returns:

a (possibly empty) Collection of the values of the response header with the given name

getHeaderNames

public Collection<String> getHeaderNames()

Description copied from interface: HttpServletResponse

Gets the names of the headers of this response.

This method considers only response headers set or added via HttpServletResponse.setHeader(java.lang.String, java.lang.String), HttpServletResponse.addHeader(java.lang.String, java.lang.String), HttpServletResponse.setDateHeader(java.lang.String, long), HttpServletResponse.addDateHeader(java.lang.String, long), HttpServletResponse.setIntHeader(java.lang.String, int), or HttpServletResponse.addIntHeader(java.lang.String, int), respectively.

Any changes to the returned Collection must not affect this HttpServletResponse.

Specified by:

getHeaderNames in interface HttpServletResponse

Returns:

a (possibly empty) Collection of the names of the headers of this response