Response (Apache Tomcat 11.0.22 API Documentation)
Description: declaration: package: org.apache.catalina.connector, class: Response

# Class Response

java.lang.Object
org.apache.catalina.connector.Response

All Implemented Interfaces:
  `HttpServletResponse, ServletResponse`

public class Response extends Object implements HttpServletResponse
Wrapper object for the Coyote response.

- ## Field Summary

  Fields
  Modifier and Type
  Field
  Description
  `protected boolean`
  `appCommitted`
  The application commit flag.
  `protected final Response`
  `coyoteResponse`
  Coyote response.
  `protected ResponseFacade`
  `facade`
  The facade associated with this response.
  `protected boolean`
  `included`
  The included flag.
  `protected final OutputBuffer`
  `outputBuffer`
  The associated output buffer.
  `protected CoyoteOutputStream`
  `outputStream`
  The associated output stream.
  `protected final CharChunk`
  `redirectURLCC`
  Recyclable buffer to hold the redirect URL.
  `protected Request`
  `request`
  The request with which this response is associated.
  `protected static final int`
  `SC_EARLY_HINTS`
  `protected static final StringManager`
  `sm`
  `protected final UEncoder`
  `urlEncoder`
  URL encoder.
  `protected boolean`
  `usingOutputStream`
  Using output stream flag.
  `protected boolean`
  `usingWriter`
  Using writer flag.
  `protected CoyoteWriter`
  `writer`
  The associated writer.

  ### Fields inherited from interface 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_MISDIRECTED_REQUEST, 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_PERMANENT_REDIRECT, 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_UNPROCESSABLE_CONTENT, SC_UNSUPPORTED_MEDIA_TYPE, SC_UPGRADE_REQUIRED, SC_USE_PROXY`

- ## Constructor Summary

  Constructors
  Constructor
  Description
  `Response(Response coyoteResponse)`
  `Response(Response coyoteResponse, int outputBufferSize)`

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `addCookie(Cookie cookie)`
  Add the specified Cookie to those that will be included with this Response.
  `void`
  `addDateHeader(String name, long value)`
  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.
  `void`
  `addSessionCookieInternal(Cookie cookie)`
  Special method for adding a session cookie as we should be overriding any previous.
  `boolean`
  `containsHeader(String name)`
  Returns a boolean indicating whether the named response header has already been set.
  `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)`
  Encodes the specified URL by including the session ID in it, or, if encoding is not needed, returns the URL unchanged.
  `void`
  `finishResponse()`
  Perform whatever actions are required to flush and close the output stream or writer, in a single operation.
  `void`
  `flushBuffer()`
  Forces any content in the buffer to be written to the client.
  `String`
  `generateCookieString(Cookie cookie)`
  `int`
  `getBufferSize()`
  Returns the actual buffer size used for the response.
  `long`
  `getBytesWritten(boolean flush)`
  `String`
  `getCharacterEncoding()`
  Returns the name of the character encoding (MIME charset) used for the body sent in this response.
  `int`
  `getContentLength()`
  `String`
  `getContentType()`
  Returns the content type used for the MIME body sent in this response.
  `long`
  `getContentWritten()`
  `Context`
  `getContext()`
  `Response`
  `getCoyoteResponse()`
  `String`
  `getHeader(String name)`
  Return the value for the specified header, or `null` if this header has not been set.
  `Collection<String>`
  `getHeaderNames()`
  Get the header names set for this HTTP response.
  `Collection<String>`
  `getHeaders(String name)`
  Return a Collection of all the header values associated with the specified header name.
  `Locale`
  `getLocale()`
  Returns the locale specified for this response using the `ServletResponse.setLocale(Locale)` method.
  `String`
  `getMessage()`
  `ServletOutputStream`
  `getOutputStream()`
  Returns a `ServletOutputStream` suitable for writing binary data in the response.
  `PrintWriter`
  `getReporter()`
  Return a PrintWriter that can be used to render error messages, regardless of whether a stream or writer has already been acquired.
  `Request`
  `getRequest()`
  `HttpServletResponse`
  `getResponse()`
  `int`
  `getStatus()`
  Get the HTTP status code for this Response.
  `Supplier<Map<String,String>>`
  `getTrailerFields()`
  Obtain the supplier of the trailer headers.
  `PrintWriter`
  `getWriter()`
  Returns a `PrintWriter` object that can send character text to the client.
  `boolean`
  `isAppCommitted()`
  Application commit flag accessor.
  `boolean`
  `isClosed()`
  Closed flag accessor.
  `boolean`
  `isCommitted()`
  Returns a boolean indicating if the response has been committed.
  `protected boolean`
  `isEncodeable(String location)`
  Return `true` if the specified URL should be encoded with a session identifier.
  `boolean`
  `isError()`
  Error flag accessor.
  `boolean`
  `isErrorReportRequired()`
  `boolean`
  `isSuspended()`
  Suspended flag accessor.
  `void`
  `recycle()`
  Release all object references, and initialize instance variables, in preparation for reuse of this object.
  `void`
  `reset()`
  Clears any data that exists in the buffer as well as the status code and headers.
  `void`
  `resetBuffer()`
  Clears the content of the underlying buffer in the response without clearing headers or status code.
  `void`
  `resetBuffer(boolean resetWriterStreamFlags)`
  Reset the data buffer and the using Writer/Stream flags but not any status or header information.
  `void`
  `resetError()`
  `void`
  `sendAcknowledgement(ContinueResponseTiming continueResponseTiming)`
  Send an acknowledgement of a request.
  `void`
  `sendEarlyHints()`
  `void`
  `sendError(int status)`
  Sends an error response to the client using the specified status code and clears the buffer.
  `void`
  `sendError(int status, String message)`
  Sends an error response to the client using the specified status code and clears the output buffer.
  `void`
  `sendRedirect(String location, int status, boolean clearBuffer)`
  Sends a redirect response to the client using the specified redirect location URL and status code, optionally clears the response buffer and commits the response.
  `void`
  `setAppCommitted(boolean appCommitted)`
  Set the application commit flag.
  `void`
  `setBufferSize(int size)`
  Sets the preferred buffer size for the body of the response.
  `void`
  `setCharacterEncoding(String encoding)`
  Sets the character encoding (MIME charset) of the response being sent to the client, for example, to UTF-8.
  `void`
  `setCharacterEncoding(Charset charset)`
  Sets the character encoding (MIME charset) of the response being sent to the client, for example, to UTF-8.
  `void`
  `setContentLength(int length)`
  Sets the length of the content body in the response In HTTP servlets, this method sets the HTTP Content-Length header.
  `void`
  `setContentLengthLong(long length)`
  Sets the length of the content body in the response In HTTP servlets, this method sets the HTTP Content-Length header.
  `void`
  `setContentType(String type)`
  Sets the content type of the response being sent to the client, if the response has not been committed yet.
  `void`
  `setDateHeader(String name, long value)`
  Sets a response header with the given name and date-value.
  `void`
  `setError()`
  Set the error flag if not already set.
  `boolean`
  `setErrorReported()`
  `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 locale)`
  Sets the locale of the response, if the response has not been committed yet.
  `void`
  `setRequest(Request request)`
  Set the Request with which this Response is associated.
  `void`
  `setResponse(HttpServletResponse applicationResponse)`
  Set a wrapped HttpServletResponse to pass to the application.
  `void`
  `setStatus(int status)`
  Sets the status code for this response.
  `void`
  `setSuspended(boolean suspended)`
  Set the suspended flag.
  `void`
  `setTrailerFields(Supplier<Map<String,String>> supplier)`
  Configure the supplier of the trailer headers.
  `protected String`
  `toAbsolute(String location)`
  Convert (if necessary) and return the absolute URL that represents the resource referenced by this possibly relative URL.
  `protected String`
  `toEncoded(String url, String sessionId)`
  Return the specified URL with the specified session identifier suitably encoded.

  ### Methods inherited from class Object

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

  ### Methods inherited from interface HttpServletResponse

  `sendRedirect, sendRedirect, sendRedirect`

- ## Field Details

  - ### sm

    protected static final StringManager sm

  - ### SC_EARLY_HINTS

    protected static final int SC_EARLY_HINTS
    See Also:
      - Constant Field Values

  - ### coyoteResponse

    protected final Response coyoteResponse
    Coyote response.

  - ### outputBuffer

    protected final OutputBuffer outputBuffer
    The associated output buffer.

  - ### outputStream

    protected CoyoteOutputStream outputStream
    The associated output stream.

  - ### writer

    protected CoyoteWriter writer
    The associated writer.

  - ### appCommitted

    protected boolean appCommitted
    The application commit flag.

  - ### included

    protected boolean included
    The included flag.

  - ### usingOutputStream

    protected boolean usingOutputStream
    Using output stream flag.

  - ### usingWriter

    protected boolean usingWriter
    Using writer flag.

  - ### urlEncoder

    protected final UEncoder urlEncoder
    URL encoder.

  - ### redirectURLCC

    protected final CharChunk redirectURLCC
    Recyclable buffer to hold the redirect URL.

  - ### request

    protected Request request
    The request with which this response is associated.

  - ### facade

    protected ResponseFacade facade
    The facade associated with this response.

- ## Constructor Details

  - ### Response

    public Response(Response coyoteResponse)

  - ### Response

    public Response(Response coyoteResponse, int outputBufferSize)

- ## Method Details

  - ### getCoyoteResponse

    public Response getCoyoteResponse()
    Returns:
      the Coyote response.

  - ### getContext

    public Context getContext()
    Returns:
      the Context within which this Request is being processed.

  - ### recycle

    public void recycle()
    Release all object references, and initialize instance variables, in preparation for reuse of this object.

  - ### getContentWritten

    public long getContentWritten()
    Returns:
      the number of bytes the application has actually written to the output stream. This excludes chunking, compression, etc. as well as headers.

  - ### getBytesWritten

    public long getBytesWritten(boolean flush)
    Parameters:
      `flush` - if `true` will perform a buffer flush first
    Returns:
      the number of bytes the actually written to the socket. This includes chunking, compression, etc. but excludes headers.

  - ### setAppCommitted

    public void setAppCommitted(boolean appCommitted)
    Set the application commit flag.
    Parameters:
      `appCommitted` - The new application committed flag value

  - ### isAppCommitted

    public boolean isAppCommitted()
    Application commit flag accessor.
    Returns:
      `true` if the application has committed the response

  - ### getRequest

    public Request getRequest()
    Returns:
      the Request with which this Response is associated.

  - ### setRequest

    public void setRequest(Request request)
    Set the Request with which this Response is associated.
    Parameters:
      `request` - The new associated request

  - ### getResponse

    public HttpServletResponse getResponse()
    Returns:
      the `ServletResponse` for which this object is the facade.

  - ### setResponse

    public void setResponse(HttpServletResponse applicationResponse)
    Set a wrapped HttpServletResponse to pass to the application. Components wishing to wrap the response should obtain the response via `getResponse()`, wrap it and then call this method with the wrapped response.
    Parameters:
      `applicationResponse` - The wrapped response to pass to the application

  - ### setSuspended

    public void setSuspended(boolean suspended)
    Set the suspended flag.
    Parameters:
      `suspended` - The new suspended flag value

  - ### isSuspended

    public boolean isSuspended()
    Suspended flag accessor.
    Returns:
      `true` if the response is suspended

  - ### isClosed

    public boolean isClosed()
    Closed flag accessor.
    Returns:
      `true` if the response has been closed

  - ### setError

    public void setError()
    Set the error flag if not already set.

  - ### isError

    public boolean isError()
    Error flag accessor.
    Returns:
      `true` if the response has encountered an error

  - ### isErrorReportRequired

    public boolean isErrorReportRequired()

  - ### setErrorReported

    public boolean setErrorReported()

  - ### resetError

    public void resetError()

  - ### finishResponse

    public void finishResponse() throws IOException
    Perform whatever actions are required to flush and close the output stream or writer, in a single operation.
    Throws:
      `IOException` - if an input/output error occurs

  - ### getContentLength

    public int getContentLength()
    Returns:
      the content length that was set or calculated for this Response.

  - ### getContentType

    public String getContentType()
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Returns the content type used for the MIME body sent in this response. The content type proper must have been specified using `ServletResponse.setContentType(String)` before the response is committed. If no content type has been specified, this method returns null. If a content type has been specified and a character encoding has been explicitly or implicitly specified as described in `ServletResponse.getCharacterEncoding()`, the charset parameter is included in the string returned. If no character encoding has been specified, the charset parameter is omitted.
    Specified by:
      `getContentType` in interface `ServletResponse`
    Returns:
      a `String` specifying the content type, for example, `text/html; charset=UTF-8`, or null

  - ### getReporter

    public PrintWriter getReporter() throws IOException
    Return a PrintWriter that can be used to render error messages, regardless of whether a stream or writer has already been acquired.
    Returns:
      Writer which can be used for error reports. If the response is not an error report returned using sendError or triggered by an unexpected exception thrown during the servlet processing (and only in that case), null will be returned if the response stream has already been used.
    Throws:
      `IOException` - if an input/output error occurs

  - ### flushBuffer

    public void flushBuffer() throws IOException
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Forces any content in the buffer to be written to the client. A call to this method automatically commits the response, meaning the status code and headers will be written.
    Specified by:
      `flushBuffer` in interface `ServletResponse`
    Throws:
      `IOException` - if an I/O occurs during the flushing of the response
    See Also:
      - `ServletResponse.setBufferSize(int)`
      - `ServletResponse.getBufferSize()`
      - `ServletResponse.isCommitted()`
      - `ServletResponse.reset()`

  - ### getBufferSize

    public int getBufferSize()
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Returns the actual buffer size used for the response. If no buffering is used, this method returns 0.
    Specified by:
      `getBufferSize` in interface `ServletResponse`
    Returns:
      the actual buffer size used
    See Also:
      - `ServletResponse.setBufferSize(int)`
      - `ServletResponse.flushBuffer()`
      - `ServletResponse.isCommitted()`
      - `ServletResponse.reset()`

  - ### getCharacterEncoding

    public String getCharacterEncoding()
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Returns the name of the character encoding (MIME charset) used for the body sent in this response. The charset for the MIME body response can be specified explicitly or implicitly. The priority order for specifying the response body is:
    1. explicitly per request using `ServletResponse.setCharacterEncoding(String)` and `ServletResponse.setContentType(String)`
    2. implicitly per request using `ServletResponse.setLocale(Locale)`
    3. per web application via the deployment descriptor or `ServletContext.setRequestCharacterEncoding(String)`
    4. container default via vendor specific configuration
    5. ISO-8859-1
    Calls made to `ServletResponse.setCharacterEncoding(String)`, `ServletResponse.setContentType(String)` or `ServletResponse.setLocale(Locale)` after `getWriter` has been called or after the response has been committed have no effect on the character encoding. If no character encoding has been specified, `ISO-8859-1` is returned.

    See RFC 2047 for more information about character encoding and MIME.

    Specified by:
      `getCharacterEncoding` in interface `ServletResponse`
    Returns:
      a `String` specifying the name of the character encoding, for example, `UTF-8`

  - ### getOutputStream

    public ServletOutputStream getOutputStream() throws IOException
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Returns a `ServletOutputStream` suitable for writing binary data in the response. The servlet container does not encode the binary data.

    Calling flush() on the ServletOutputStream commits the response. Either this method or `ServletResponse.getWriter()` may be called to write the body, not both.

    Specified by:
      `getOutputStream` in interface `ServletResponse`
    Returns:
      a `ServletOutputStream` for writing binary data
    Throws:
      `IOException` - if an input or output exception occurred
    See Also:
      - `ServletResponse.getWriter()`

  - ### getLocale

    public Locale getLocale()
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Returns the locale specified for this response using the `ServletResponse.setLocale(Locale)` method. Calls made to `setLocale` after the response is committed have no effect.
    Specified by:
      `getLocale` in interface `ServletResponse`
    Returns:
      The locale specified for this response using the `ServletResponse.setLocale(Locale)` method. If no locale has been specified, the container's default locale is returned.
    See Also:
      - `ServletResponse.setLocale(Locale)`

  - ### getWriter

    public PrintWriter getWriter() throws IOException
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Returns a `PrintWriter` object that can send character text to the client. The `PrintWriter` uses the character encoding returned by `ServletResponse.getCharacterEncoding()`. If the response's character encoding has not been specified as described in `getCharacterEncoding` (i.e., the method just returns the default value `ISO-8859-1`), `getWriter` updates it to `ISO-8859-1`.

    Calling flush() on the `PrintWriter` commits the response.

    Either this method or `ServletResponse.getOutputStream()` may be called to write the body, not both.

    Specified by:
      `getWriter` in interface `ServletResponse`
    Returns:
      a `PrintWriter` object that can return character data to the client
    Throws:
      `IOException` - if an input or output exception occurred
    See Also:
      - `ServletResponse.getOutputStream()`
      - `ServletResponse.setCharacterEncoding(String)`

  - ### isCommitted

    public boolean isCommitted()
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Returns a boolean indicating if the response has been committed. A committed response has already had its status code and headers written.
    Specified by:
      `isCommitted` in interface `ServletResponse`
    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 interface: `jakarta.servlet.ServletResponse`
    Clears any data that exists in the buffer as well as the status code and headers. If the response has been committed, this method throws an `IllegalStateException`.
    Specified by:
      `reset` in interface `ServletResponse`
    See Also:
      - `ServletResponse.setBufferSize(int)`
      - `ServletResponse.getBufferSize()`
      - `ServletResponse.flushBuffer()`
      - `ServletResponse.isCommitted()`

  - ### resetBuffer

    public void resetBuffer()
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Clears the content of the underlying buffer in the response without clearing headers or status code. If the response has been committed, this method throws an `IllegalStateException`.
    Specified by:
      `resetBuffer` in interface `ServletResponse`
    See Also:
      - `ServletResponse.setBufferSize(int)`
      - `ServletResponse.getBufferSize()`
      - `ServletResponse.isCommitted()`
      - `ServletResponse.reset()`

  - ### resetBuffer

    public void resetBuffer(boolean resetWriterStreamFlags)
    Reset the data buffer and the using Writer/Stream flags but not any status or header information.
    Parameters:
      `resetWriterStreamFlags` - `true` if the internal `usingWriter`, `usingOutputStream`, `isCharacterEncodingSet` flags should also be reset
    Throws:
      `IllegalStateException` - if the response has already been committed

  - ### setBufferSize

    public void setBufferSize(int size)
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Sets the preferred buffer size for the body of the response. The servlet container will use a buffer at least as large as the size requested. The actual buffer size used can be found using `getBufferSize`.

    A larger buffer allows more content to be written before anything is actually sent, thus providing the servlet with more time to set appropriate status codes and headers. A smaller buffer decreases server memory load and allows the client to start receiving data more quickly.

    This method must be called before any response body content is written; if content has been written or the response object has been committed, this method throws an `IllegalStateException`.

    Specified by:
      `setBufferSize` in interface `ServletResponse`
    Parameters:
      `size` - the preferred buffer size
    See Also:
      - `ServletResponse.getBufferSize()`
      - `ServletResponse.flushBuffer()`
      - `ServletResponse.isCommitted()`
      - `ServletResponse.reset()`

  - ### setContentLength

    public void setContentLength(int length)
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Sets the length of the content body in the response In HTTP servlets, this method sets the HTTP Content-Length header.
    Specified by:
      `setContentLength` in interface `ServletResponse`
    Parameters:
      `length` - an integer specifying the length of the content being returned to the client; sets the Content-Length header

  - ### setContentLengthLong

    public void setContentLengthLong(long length)
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Sets the length of the content body in the response In HTTP servlets, this method sets the HTTP Content-Length header.
    Specified by:
      `setContentLengthLong` in interface `ServletResponse`
    Parameters:
      `length` - 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 interface: `jakarta.servlet.ServletResponse`
    Sets the content type of the response being sent to the client, if the response has not been committed yet. The given content type may include a character encoding specification, for example, `text/html;charset=UTF-8`. The response's character encoding is only set from the given content type if this method is called before `getWriter` is called.

    This method may be called repeatedly to change content type and character encoding. This method has no effect if called after the response has been committed. It does not set the response's character encoding if it is called after `getWriter` has been called or after the response has been committed.

    Containers must communicate the content type and the character encoding used for the servlet response's writer to the client if the protocol provides a way for doing so. In the case of HTTP, the `Content-Type` header is used.

    Specified by:
      `setContentType` in interface `ServletResponse`
    Parameters:
      `type` - a `String` specifying the MIME type of the content
    See Also:
      - `ServletResponse.setLocale(Locale)`
      - `ServletResponse.setCharacterEncoding(String)`
      - `ServletResponse.getOutputStream()`
      - `ServletResponse.getWriter()`

  - ### setCharacterEncoding

    public void setCharacterEncoding(String encoding)
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Sets the character encoding (MIME charset) of the response being sent to the client, for example, to UTF-8. If the character encoding has already been set by container default, ServletContext default, `ServletResponse.setCharacterEncoding(Charset)`, `ServletResponse.setContentType(String)` or `ServletResponse.setLocale(Locale)`, this method overrides it. Calling `ServletResponse.setContentType(String)` with the `String` of `text/html` and calling this method with the `String` of `UTF-8` is equivalent with calling `setContentType` with the `String` of `text/html; charset=UTF-8`.

    This method can be called repeatedly to change the character encoding. This method has no effect if it is called after `getWriter` has been called or after the response has been committed.

    Containers must communicate the character encoding used for the servlet response's writer to the client if the protocol provides a way for doing so. In the case of HTTP, the character encoding is communicated as part of the `Content-Type` header for text media types. Note that the character encoding cannot be communicated via HTTP headers if the servlet does not specify a content type; however, it is still used to encode text written via the servlet response's writer.

    Specified by:
      `setCharacterEncoding` in interface `ServletResponse`
    Parameters:
      `encoding` - a String specifying only the character set defined by IANA Character Sets
    See Also:
      - #setLocale
      - `ServletResponse.setCharacterEncoding(Charset)`

  - ### setCharacterEncoding

    public void setCharacterEncoding(Charset charset)
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Sets the character encoding (MIME charset) of the response being sent to the client, for example, to UTF-8. If the character encoding has already been set by container default, ServletContext default, `ServletResponse.setCharacterEncoding(String)`, `ServletResponse.setContentType(String)` or `ServletResponse.setLocale(Locale)`, this method overrides it. Calling `ServletResponse.setContentType(String)` with the `String` of `text/html` and calling this method with the `StandardCharsets.UTF-8` is equivalent with calling `setContentType` with the `String` of `text/html; charset=UTF-8`.

    This method can be called repeatedly to change the character encoding. This method has no effect if it is called after `getWriter` has been called or after the response has been committed.

    Containers must communicate the character encoding used for the servlet response's writer to the client if the protocol provides a way for doing so. In the case of HTTP, the character encoding is communicated as part of the `Content-Type` header for text media types. Note that the character encoding cannot be communicated via HTTP headers if the servlet does not specify a content type; however, it is still used to encode text written via the servlet response's writer.

    Specified by:
      `setCharacterEncoding` in interface `ServletResponse`
    Parameters:
      `charset` - The encoding to use or `null`
    See Also:
      - #setLocale
      - `ServletResponse.setCharacterEncoding(String)`

  - ### setLocale

    public void setLocale(Locale locale)
    Description copied from interface: `jakarta.servlet.ServletResponse`
    Sets the locale of the response, if the response has not been committed yet. It also sets the response's character encoding appropriately for the locale, if the character encoding has not been explicitly set using `ServletResponse.setContentType(String)`, `ServletResponse.setCharacterEncoding(String)` or `ServletResponse.setCharacterEncoding(Charset)`, `getWriter` hasn't been called yet, and the response hasn't been committed yet. If the deployment descriptor contains a `locale-encoding-mapping-list` element, and that element provides a mapping for the given locale, that mapping is used. Otherwise, the mapping from locale to character encoding is container dependent.

    This method may be called repeatedly to change locale and character encoding. The method has no effect if called after the response has been committed. It does not set the response's character encoding if it is called after `ServletResponse.setContentType(String)` has been called with a charset specification, after `ServletResponse.setCharacterEncoding(String)` has been called, after `getWriter` has been called, or after the response has been committed.

    Containers must communicate the locale and the character encoding used for the servlet response's writer to the client if the protocol provides a way for doing so. In the case of HTTP, the locale is communicated via the `Content-Language` header, the character encoding as part of the `Content-Type` header for text media types. Note that the character encoding cannot be communicated via HTTP headers if the servlet does not specify a content type; however, it is still used to encode text written via the servlet response's writer.

    Specified by:
      `setLocale` in interface `ServletResponse`
    Parameters:
      `locale` - the locale of the response
    See Also:
      - `ServletResponse.getLocale()`
      - `ServletResponse.setContentType(String)`
      - `ServletResponse.setCharacterEncoding(String)`
      - `ServletResponse.setCharacterEncoding(Charset)`

  - ### getHeader

    public String getHeader(String name)
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Return the value for the specified header, or `null` if this header has not been set. If more than one value was added for this name, only the first is returned; use `HttpServletResponse.getHeaders(String)` to retrieve all of them.
    Specified by:
      `getHeader` in interface `HttpServletResponse`
    Parameters:
      `name` - Header name to look up
    Returns:
      The first value for the specified header. This is the raw value so if multiple values are specified in the first header then they will be returned as a single header value .

  - ### getHeaderNames

    public Collection<String> getHeaderNames()
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Get the header names set for this HTTP response.
    Specified by:
      `getHeaderNames` in interface `HttpServletResponse`
    Returns:
      The header names set for this HTTP response.

  - ### getHeaders

    public Collection<String> getHeaders(String name)
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Return a Collection of all the header values associated with the specified header name.
    Specified by:
      `getHeaders` in interface `HttpServletResponse`
    Parameters:
      `name` - Header name to look up
    Returns:
      The values for the specified header. These are the raw values so if multiple values are specified in a single header that will be returned as a single header value.

  - ### getMessage

    public String getMessage()
    Returns:
      the error message that was set with `sendError()` for this Response.

  - ### getStatus

    public int getStatus()
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Get the HTTP status code for this Response.
    Specified by:
      `getStatus` in interface `HttpServletResponse`
    Returns:
      The HTTP status code for this Response

  - ### addCookie

    public void addCookie(Cookie cookie)
    Add the specified Cookie to those that will be included with this Response.
    Specified by:
      `addCookie` in interface `HttpServletResponse`
    Parameters:
      `cookie` - Cookie to be added

  - ### addSessionCookieInternal

    public void addSessionCookieInternal(Cookie cookie)
    Special method for adding a session cookie as we should be overriding any previous.
    Parameters:
      `cookie` - The new session cookie to add the response

  - ### generateCookieString

    public String generateCookieString(Cookie cookie)

  - ### addDateHeader

    public void addDateHeader(String name, long value)
    Description copied from interface: `jakarta.servlet.http.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
      `value` - the additional date value
    See Also:
      - `HttpServletResponse.setDateHeader(String, long)`

  - ### addHeader

    public void addHeader(String name, String value)
    Description copied from interface: `jakarta.servlet.http.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
    See Also:
      - `HttpServletResponse.setHeader(String, String)`

  - ### addIntHeader

    public void addIntHeader(String name, int value)
    Description copied from interface: `jakarta.servlet.http.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(String, int)`

  - ### containsHeader

    public boolean containsHeader(String name)
    Description copied from interface: `jakarta.servlet.http.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

  - ### setTrailerFields

    public void setTrailerFields(Supplier<Map<String,String>> supplier)
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Configure the supplier of the trailer headers. The supplier will be called in the scope of the thread that completes the response.
    Trailers that don't meet the requirements of RFC 7230, section 4.1.2 will be ignored.
    The default implementation is a NO-OP.
    Specified by:
      `setTrailerFields` in interface `HttpServletResponse`
    Parameters:
      `supplier` - The supplier for the trailer headers

  - ### getTrailerFields

    public Supplier<Map<String,String>> getTrailerFields()
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Obtain the supplier of the trailer headers.
    The default implementation returns null.
    Specified by:
      `getTrailerFields` in interface `HttpServletResponse`
    Returns:
      The supplier for the trailer headers

  - ### encodeRedirectURL

    public String encodeRedirectURL(String url)
    Description copied from interface: `jakarta.servlet.http.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. 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.

    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(String)`

  - ### encodeURL

    public String encodeURL(String url)
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Encodes the specified URL by including the session ID in it, 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.

    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.

  - ### sendAcknowledgement

    public void sendAcknowledgement(ContinueResponseTiming continueResponseTiming)
    Send an acknowledgement of a request.
    Parameters:
      `continueResponseTiming` - Indicates when the request for the ACK originated so it can be compared with the configured timing for ACK responses.

  - ### sendEarlyHints

    public void sendEarlyHints()

  - ### sendError

    public void sendError(int status) throws IOException
    Sends an error response to the client using the specified status code and clears the buffer. This is equivalent to calling `HttpServletResponse.sendError(int, String)` with the same status code and `null` for the message.

    Calling `sendError` with a status code of 103 differs from the usual behavior. Sending 103 will trigger the container to send a "103 Early Hints" informational response including all current headers. The application can continue to use the request and response after calling sendError with a 103 status code, including triggering a more typical response of any type.

    Starting with Tomcat 12, applications should use `sendEarlyHints()`.

    Specified by:
      `sendError` in interface `HttpServletResponse`
    Parameters:
      `status` - the error status code
    Throws:
      `IOException` - If an input or output exception occurs

  - ### sendError

    public void sendError(int status, String message) throws IOException
    Sends an error response to the client using the specified status code and clears the output 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", leaving cookies and other headers unmodified. 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.

    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.

    Calling `sendError` with a status code of 103 differs from the usual behavior. Sending 103 will trigger the container to send a "103 Early Hints" informational response including all current headers. The application can continue to use the request and response after calling sendError with a 103 status code, including triggering a more typical response of any type.

    Starting with Tomcat 12, applications should use `sendEarlyHints()`.

    Specified by:
      `sendError` in interface `HttpServletResponse`
    Parameters:
      `status` - the error status code
      `message` - the descriptive message
    Throws:
      `IOException` - If an input or output exception occurs

  - ### sendRedirect

    public void sendRedirect(String location, int status, boolean clearBuffer) throws IOException
    Description copied from interface: `jakarta.servlet.http.HttpServletResponse`
    Sends a redirect response to the client using the specified redirect location URL and status code, optionally clears the response buffer and commits the response. If the response buffer is cleared, it will be replaced with a short hypertext note as per RFC 9110.

    This method has no effect if called from an include.

    This method accepts both relative and absolute URLs. Absolute URLs passed to this method are used as provided as the redirect location URL. Relative URLs are converted to absolute URLs unless a container specific feature/option is provided that controls whether relative URLs passed to this method are converted to absolute URLs or used as provided for the redirect location URL. If converting a relative URL to an absolute URL then:

    - 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 (can be absolute or relative)
      `status` - the status code to use for the redirect
      `clearBuffer` - if `true`, clear the buffer and replace it with the data set by this method otherwise retain the existing buffer
    Throws:
      `IOException` - If an input or output exception occurs

  - ### setDateHeader

    public void setDateHeader(String name, long value)
    Description copied from interface: `jakarta.servlet.http.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
      `value` - the assigned date value
    See Also:
      - `HttpServletResponse.containsHeader(String)`
      - `HttpServletResponse.addDateHeader(String, long)`

  - ### setHeader

    public void setHeader(String name, String value)
    Description copied from interface: `jakarta.servlet.http.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
    See Also:
      - `HttpServletResponse.containsHeader(String)`
      - `HttpServletResponse.addHeader(String, String)`

  - ### setIntHeader

    public void setIntHeader(String name, int value)
    Description copied from interface: `jakarta.servlet.http.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(String)`
      - `HttpServletResponse.addIntHeader(String, int)`

  - ### setStatus

    public void setStatus(int status)
    Description copied from interface: `jakarta.servlet.http.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 status codes SC_OK or SC_MOVED_TEMPORARILY). If there is an error, and the caller wishes to invoke an error-page defined in the web application, the `sendError` method should be used instead.

    The container clears the buffer and sets the Location header, preserving cookies and other headers.

    Specified by:
      `setStatus` in interface `HttpServletResponse`
    Parameters:
      `status` - the status code
    See Also:
      - `HttpServletResponse.sendError(int, String)`

  - ### isEncodeable

    protected boolean isEncodeable(String location)
    Return `true` if the specified URL should be encoded with a session identifier. This will be true if all of the following conditions are met:
    - The request we are responding to asked for a valid session
    - The requested session ID was not received via a cookie
    - The specified URL points back to somewhere within the web application that is responding to this request
    Parameters:
      `location` - Absolute URL to be validated
    Returns:
      `true` if the URL should be encoded

  - ### toAbsolute

    protected String toAbsolute(String location)
    Convert (if necessary) and return the absolute URL that represents the resource referenced by this possibly relative URL. If this URL is already absolute, return it unchanged.
    Parameters:
      `location` - URL to be (possibly) converted and then returned
    Returns:
      the encoded URL
    Throws:
      `IllegalArgumentException` - if a MalformedURLException is thrown when converting the relative URL to an absolute one

  - ### toEncoded

    protected String toEncoded(String url, String sessionId)
    Return the specified URL with the specified session identifier suitably encoded.
    Parameters:
      `url` - URL to be encoded with the session id
      `sessionId` - Session id to be included in the encoded URL
    Returns:
      the encoded URL