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/*
* Copyright (c) 1997, 2020 Oracle and/or its affiliates and others.
* All rights reserved.
* Copyright 2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package jakarta.servlet.http;
import jakarta.servlet.ServletResponse;
import java.io.IOException;
import java.util.Collection;
import java.util.Map;
import java.util.function.Supplier;
/**
*
* Extends the {@link ServletResponse} interface to provide HTTP-specific functionality in sending a response. For
* example, it has methods to access HTTP headers and cookies.
*
*
* The servlet container creates an HttpServletResponse
object and passes it as an argument to the
* servlet's service methods (doGet
, doPost
, etc).
*
*
* @author Various
*
* @see jakarta.servlet.ServletResponse
*
*/
public interface HttpServletResponse extends ServletResponse {
/**
* Adds the specified cookie to the response. This method can be called multiple times to set more than one cookie.
*
* @param cookie the Cookie to return to the client
*
*/
public void addCookie(Cookie cookie);
/**
* Returns a boolean indicating whether the named response header has already been set.
*
* @param name the header name
* @return true
if the named response header has already been set; false
otherwise
*/
public boolean containsHeader(String name);
/**
* 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.
*
* @param url the url to be encoded.
* @return the encoded URL if encoding is needed; the unchanged URL otherwise.
* @exception IllegalArgumentException if the url is not valid
*/
public String encodeURL(String url);
/**
* 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.
*
* @param url the url to be encoded.
* @return the encoded URL if encoding is needed; the unchanged URL otherwise.
* @exception IllegalArgumentException if the url is not valid
*
* @see #sendRedirect
* @see #encodeUrl
*/
public String encodeRedirectURL(String url);
/**
* @deprecated As of version 2.1, use encodeURL(String url) instead
*
* @param url the url to be encoded.
* @return the encoded URL if encoding is needed; the unchanged URL otherwise.
* @exception IllegalArgumentException if the url is not valid
*/
@Deprecated
public String encodeUrl(String url);
/**
* @deprecated As of version 2.1, use encodeRedirectURL(String url) instead
*
* @param url the url to be encoded.
* @return the encoded URL if encoding is needed; the unchanged URL otherwise.
* @exception IllegalArgumentException if the url is not valid
*/
@Deprecated
public String encodeRedirectUrl(String url);
/**
*
* 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 caller is not responsible for escaping or re-encoding the message
* to ensure it is safe with respect to the current response encoding and content type. This aspect of safety is the
* responsibility of the container, as it is generating the error page containing the message. 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.
*
* @param sc the error status code
* @param msg the descriptive message
* @exception IOException If an input or output exception occurs
* @exception IllegalStateException If the response was committed
*/
public void sendError(int sc, String msg) throws IOException;
/**
* 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.
*
* @param sc the error status code
* @exception IOException If an input or output exception occurs
* @exception IllegalStateException If the response was committed before this method call
*/
public void sendError(int sc) throws IOException;
/**
* 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
* {@link #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.
*
* @param location the redirect location URL
* @exception IOException If an input or output exception occurs
* @exception IllegalStateException If the response was committed or if a partial URL is given and cannot be converted
* into a valid URL
*/
public void sendRedirect(String location) throws IOException;
/**
*
* 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.
*
* @param name the name of the header to set
* @param date the assigned date value
*
* @see #containsHeader
* @see #addDateHeader
*/
public void setDateHeader(String name, long date);
/**
*
* 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.
*
* @param name the name of the header to set
* @param date the additional date value
*
* @see #setDateHeader
*/
public void addDateHeader(String name, long date);
/**
*
* 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.
*
* @param name the name of the header
* @param 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 #containsHeader
* @see #addHeader
*/
public void setHeader(String name, String value);
/**
* Adds a response header with the given name and value. This method allows response headers to have multiple values.
*
* @param name the name of the header
* @param 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 #setHeader
*/
public void addHeader(String name, String value);
/**
* 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.
*
* @param name the name of the header
* @param value the assigned integer value
*
* @see #containsHeader
* @see #addIntHeader
*/
public void setIntHeader(String name, int value);
/**
* Adds a response header with the given name and integer value. This method allows response headers to have multiple
* values.
*
* @param name the name of the header
* @param value the assigned integer value
*
* @see #setIntHeader
*/
public void addIntHeader(String name, int value);
/**
* 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
* {@link #sendError} 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.
*
* @param sc the status code
*
* @see #sendError
*/
public void setStatus(int sc);
/**
* @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.
*
* @param sc the status code
* @param sm the status message
*/
@Deprecated
public void setStatus(int sc, String sm);
/**
* Gets the current status code of this response.
*
* @return the current status code of this response
*
* @since Servlet 3.0
*/
public int getStatus();
/**
* 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 {@link #setHeader}, {@link #addHeader},
* {@link #setDateHeader}, {@link #addDateHeader}, {@link #setIntHeader}, or {@link #addIntHeader}, respectively.
*
* @param name the name of the response header whose value to return
*
* @return 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
*
* @since Servlet 3.0
*/
public String getHeader(String name);
/**
* Gets the values of the response header with the given name.
*
*
* This method considers only response headers set or added via {@link #setHeader}, {@link #addHeader},
* {@link #setDateHeader}, {@link #addDateHeader}, {@link #setIntHeader}, or {@link #addIntHeader}, respectively.
*
*
* Any changes to the returned Collection
must not affect this HttpServletResponse
.
*
* @param name the name of the response header whose values to return
*
* @return a (possibly empty) Collection
of the values of the response header with the given name
*
* @since Servlet 3.0
*/
public Collection getHeaders(String name);
/**
* Gets the names of the headers of this response.
*
*
* This method considers only response headers set or added via {@link #setHeader}, {@link #addHeader},
* {@link #setDateHeader}, {@link #addDateHeader}, {@link #setIntHeader}, or {@link #addIntHeader}, respectively.
*
*
* Any changes to the returned Collection
must not affect this HttpServletResponse
.
*
* @return a (possibly empty) Collection
of the names of the headers of this response
*
* @since Servlet 3.0
*/
public Collection getHeaderNames();
/**
* Sets the supplier of trailer headers.
*
*
* The trailer header field value is defined as a comma-separated list (see Section 3.2.2 and Section 4.1.2 of RFC
* 7230).
*
*
*
* The supplier will be called within the scope of whatever thread/call causes the response content to be completed.
* Typically this will be any thread calling close() on the output stream or writer.
*
*
*
* The trailers that run afoul of the provisions of section 4.1.2 of RFC 7230 are ignored.
*
*
*
* The RFC requires the name of every key that is to be in the supplied Map is included in the comma separated list that
* is the value of the "Trailer" response header. The application is responsible for ensuring this requirement is met.
* Failure to do so may lead to interoperability failures.
*
*
* @implSpec The default implementation is a no-op.
*
* @param supplier the supplier of trailer headers
*
* @exception IllegalStateException if it is invoked after the response has has been committed, or the trailer is not
* supported in the request, for instance, the underlying protocol is HTTP 1.0, or the response is not in chunked
* encoding in HTTP 1.1.
*
* @since Servlet 4.0
*/
default public void setTrailerFields(Supplier