javax.servlet.http.PushBuilder Maven / Gradle / Ivy
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package javax.servlet.http;
import java.util.Set;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
* Build a request to be pushed.
*
* According section 8.2 of RFC 7540, a promised request must be cacheable and
* safe without a request body.
*
* A PushBuilder is obtained by calling {@link
* HttpServletRequest#newPushBuilder()}. Each call to this method will
* a new instance of a PushBuilder based off the current {@code
* HttpServletRequest}, or null. Any mutations to the returned PushBuilder are
* not reflected on future returns.
*
* The instance is initialized as follows:
*
*
*
* - The method is initialized to "GET"
*
* - The existing request headers of the current {@link HttpServletRequest}
* are added to the builder, except for:
*
*
* - Conditional headers (defined in RFC 7232)
*
- Range headers
*
- Expect headers
*
- Authorization headers
*
- Referrer headers
*
*
*
*
* - If the request was authenticated, an Authorization header will
* be set with a container generated token that will result in equivalent
* Authorization for the pushed request.
*
* - The session ID will be the value returned from {@link
* HttpServletRequest#getRequestedSessionId()}, unless {@link
* HttpServletRequest#getSession(boolean)} has previously been called to
* create a new {@link HttpSession} prior to the call to create the
* {@code PushBuilder}, in which case the new session ID will be used as
* the PushBuilder's requested session ID. Note that the session ID
* returned from the request can effectively come from one of two
* "sources": a cookie or the URL (as specified in {@link
* HttpServletRequest#isRequestedSessionIdFromCookie} and {@link
* HttpServletRequest#isRequestedSessionIdFromURL}, respectively). The
* session ID for the {@code PushBuilder} will also come from the same
* source as the request.
*
* - The Referer(sic) header will be set to {@link
* HttpServletRequest#getRequestURL()} plus any {@link
* HttpServletRequest#getQueryString()}
*
* - If {@link HttpServletResponse#addCookie(Cookie)} has been called
* on the associated response, then a corresponding Cookie header will be added
* to the PushBuilder, unless the {@link Cookie#getMaxAge()} is <=0, in which
* case the Cookie will be removed from the builder.
*
*
*
* The {@link #path} method must be called on the {@code PushBuilder}
* instance before the call to {@link #push}. Failure to do so must
* cause an exception to be thrown from {@link
* #push}, as specified in that method.
*
* A PushBuilder can be customized by chained calls to mutator
* methods before the {@link #push()} method is called to initiate an
* asynchronous push request with the current state of the builder.
* After the call to {@link #push()}, the builder may be reused for
* another push, however the implementation must make it so the {@link
* #path(String)} and conditional headers (defined in RFC 7232)
* values are cleared before returning from {@link #push}.
* All other values are retained over calls to {@link #push()}.
*
* @since Servlet 4.0
*/
public interface PushBuilder {
/**
*
Set the method to be used for the push.
*
* @throws NullPointerException if the argument is {@code null}
*
* @throws IllegalArgumentException if the argument is the empty String,
* or any non-cacheable or unsafe methods defined in RFC 7231,
* which are POST, PUT, DELETE, CONNECT, OPTIONS and TRACE.
*
* @param method the method to be used for the push.
* @return this builder.
*/
public PushBuilder method(String method);
/**
* Set the query string to be used for the push.
*
* The query string will be appended to any query String included in a call
* to {@link #path(String)}. Any duplicate parameters must be preserved.
* This method should be used instead of a query in {@link #path(String)}
* when multiple {@link #push()} calls are to be made with the same
* query string.
* @param queryString the query string to be used for the push.
* @return this builder.
*/
public PushBuilder queryString(String queryString);
/**
* Set the SessionID to be used for the push.
* The session ID will be set in the same way it was on the associated request (ie
* as a cookie if the associated request used a cookie, or as a url parameter if
* the associated request used a url parameter).
* Defaults to the requested session ID or any newly assigned session id from
* a newly created session.
* @param sessionId the SessionID to be used for the push.
* @return this builder.
*/
public PushBuilder sessionId(String sessionId);
/**
* Set a request header to be used for the push. If the builder has an
* existing header with the same name, its value is overwritten.
*
* @param name The header name to set
* @param value The header value to set
* @return this builder.
*/
public PushBuilder setHeader(String name, String value);
/**
* Add a request header to be used for the push.
* @param name The header name to add
* @param value The header value to add
* @return this builder.
*/
public PushBuilder addHeader(String name, String value);
/**
* Remove the named request header. If the header does not exist, take
* no action.
*
* @param name The name of the header to remove
* @return this builder.
*/
public PushBuilder removeHeader(String name);
/**
* Set the URI path to be used for the push. The path may start
* with "/" in which case it is treated as an absolute path,
* otherwise it is relative to the context path of the associated
* request. There is no path default and {@link #path(String)} must
* be called before every call to {@link #push()}. If a query
* string is present in the argument {@code path}, its contents must
* be merged with the contents previously passed to {@link
* #queryString}, preserving duplicates.
*
* @param path the URI path to be used for the push, which may include a
* query string.
* @return this builder.
*/
public PushBuilder path(String path);
/**
* Push a resource given the current state of the builder,
* the method must be non-blocking.
*
* Push a resource based on the current state of the PushBuilder.
* Calling this method does not guarantee the resource will actually
* be pushed, since it is possible the client can decline acceptance
* of the pushed resource using the underlying HTTP/2 protocol.
*
* If the builder has a session ID, then the pushed request will
* include the session ID either as a Cookie or as a URI parameter
* as appropriate. The builders query string is merged with any
* passed query string.
*
* Before returning from this method, the builder has its path,
* conditional headers (defined in RFC 7232) nulled. All other fields
* are left as is for possible reuse in another push.
*
* @throws IllegalStateException if there was no call to {@link
* #path} on this instance either between its instantiation or the
* last call to {@code push()} that did not throw an
* IllegalStateException.
*/
public void push();
/**
* Return the method to be used for the push.
*
* @return the method to be used for the push.
*/
public String getMethod();
/**
* Return the query string to be used for the push.
*
* @return the query string to be used for the push.
*/
public String getQueryString();
/**
* Return the SessionID to be used for the push.
*
* @return the SessionID to be used for the push.
*/
public String getSessionId();
/**
* Return the set of header to be used for the push.
*
* The returned set is not backed by the {@code PushBuilder} object,
* so changes in the returned set are not reflected in the
* {@code PushBuilder} object, and vice-versa.
*
* @return the set of header to be used for the push.
*/
public Set getHeaderNames();
/**
* Return the header of the given name to be used for the push.
* @param name the name of the header
*
* @return the header of the given name to be used for the push.
*/
public String getHeader(String name);
/**
* Return the URI path to be used for the push.
*
* @return the URI path to be used for the push.
*/
public String getPath();
}