https://github.com/eclipse-ee4j/jaxrs-api: Jakarta RESTful Web Services (Eclipse Foundation) 
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 * Copyright (c) 2010, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package jakarta.ws.rs.core;

import java.util.Date;
import java.util.List;

import jakarta.ws.rs.core.Response.ResponseBuilder;


An injectable helper for request processing, all methods throw an IllegalStateException if called outside the scope of a request (e.g. from a provider constructor). Precondition processing (see the evaluatePreconditions methods) can result in either a null return value to indicate that preconditions have been met and that the request should continue, or a non-null return value to indicate that preconditions were not met. In the event that preconditions were not met, the returned ResponseBuilder instance will have an appropriate status and will also include a Vary header if the selectVariant(List<Variant>) method was called prior to to calling evaluatePreconditions. It is the responsibility of the caller to check the status and add additional metadata if required. E.g., see HTTP/1.1, section 10.3.5 for details of the headers that are expected to accompany a 304 Not Modified response. 
Author:Paul Sandoz, Marc Hadley, Marek Potociar
Since:1.0
/**
 * An injectable helper for request processing, all methods throw an {@link IllegalStateException} if called outside the
 * scope of a request (e.g. from a provider constructor).
 *
 * Precondition processing (see the {@code evaluatePreconditions} methods) can result in either a {@code null} return
 * value to indicate that preconditions have been met and that the request should continue, or a non-{@code null} return
 * value to indicate that preconditions were not met. In the event that preconditions were not met, the returned
 * {@code ResponseBuilder} instance will have an appropriate status and will also include a {@code Vary} header if the
 * {@link #selectVariant(List)} method was called prior to to calling {@code evaluatePreconditions}. It is the
 * responsibility of the caller to check the status and add additional metadata if required. E.g., see
 * <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.3.5">HTTP/1.1, section 10.3.5</a> for details
 * of the headers that are expected to accompany a {@code 304 Not Modified} response.
 *
 * @author Paul Sandoz
 * @author Marc Hadley
 * @author Marek Potociar
 * @since 1.0
 */
public interface Request {

    
Get the request method, e.g. GET, POST, etc.

See Also:
Returns:the request method.
/**
     * Get the request method, e.g. GET, POST, etc.
     *
     * @return the request method.
     * @see jakarta.ws.rs.HttpMethod
     */
    public String getMethod();

    
Select the representation variant that best matches the request. Returns null in case there is no matching variant in the list. 

More explicit variants are chosen ahead of less explicit ones. A vary header is computed from the supplied list and
automatically added to the response.



Params:
  • variants – a list of Variant that describe all of the available representation variants.
Throws:
See Also:
Returns:the variant that best matches the request or null if there's no match.
/**
     * Select the representation variant that best matches the request. Returns {@code null} in case there is no matching
     * variant in the list.
     * <p>
     * More explicit variants are chosen ahead of less explicit ones. A vary header is computed from the supplied list and
     * automatically added to the response.
     * </p>
     *
     * @param variants a list of Variant that describe all of the available representation variants.
     * @return the variant that best matches the request or {@code null} if there's no match.
     * @throws java.lang.IllegalArgumentException if variants is empty or {@code null}.
     * @throws java.lang.IllegalStateException if called outside the scope of a request.
     * @see Variant.VariantListBuilder
     */
    public Variant selectVariant(List<Variant> variants);

    
Evaluate request preconditions based on the passed in value.

Params:
  • eTag – an ETag for the current state of the resource
Throws:
Returns:null if the preconditions are met or a ResponseBuilder set with the appropriate status if the preconditions are not met. A returned ResponseBuilder will include an ETag header set with the value of eTag, provided none of the precondition evaluation has failed, in which case the ETag header would not be included and the status code of the returned ResponseBuilder would be set to Status.PRECONDITION_FAILED.
/**
     * Evaluate request preconditions based on the passed in value.
     *
     * @param eTag an ETag for the current state of the resource
     * @return {@code null} if the preconditions are met or a {@code ResponseBuilder} set with the appropriate status if the
     * preconditions are not met. A returned {@code ResponseBuilder} will include an ETag header set with the value of eTag,
     * provided none of the precondition evaluation has failed, in which case the ETag header would not be included and the
     * status code of the returned {@code ResponseBuilder} would be set to {@link Response.Status#PRECONDITION_FAILED}.
     * @throws java.lang.IllegalArgumentException if eTag is {@code null}.
     * @throws java.lang.IllegalStateException if called outside the scope of a request.
     */
    public ResponseBuilder evaluatePreconditions(EntityTag eTag);

    
Evaluate request preconditions based on the passed in value.

Params:
  • lastModified – a date that specifies the modification date of the resource
Throws:
Returns:null if the preconditions are met or a ResponseBuilder set with the appropriate status if the preconditions are not met.
/**
     * Evaluate request preconditions based on the passed in value.
     *
     * @param lastModified a date that specifies the modification date of the resource
     * @return {@code null} if the preconditions are met or a {@code ResponseBuilder} set with the appropriate status if the
     * preconditions are not met.
     * @throws java.lang.IllegalArgumentException if lastModified is {@code null}.
     * @throws java.lang.IllegalStateException if called outside the scope of a request.
     */
    public ResponseBuilder evaluatePreconditions(Date lastModified);

    
Evaluate request preconditions based on the passed in value.

Params:
  • lastModified – a date that specifies the modification date of the resource
  • eTag – an ETag for the current state of the resource
Throws:
Returns:null if the preconditions are met or a ResponseBuilder set with the appropriate status if the preconditions are not met. A returned ResponseBuilder will include an ETag header set with the value of eTag, provided none of the precondition evaluation has failed, in which case the ETag header would not be included and the status code of the returned ResponseBuilder would be set to Status.PRECONDITION_FAILED.
/**
     * Evaluate request preconditions based on the passed in value.
     *
     * @param lastModified a date that specifies the modification date of the resource
     * @param eTag an ETag for the current state of the resource
     * @return {@code null} if the preconditions are met or a {@code ResponseBuilder} set with the appropriate status if the
     * preconditions are not met. A returned {@code ResponseBuilder} will include an ETag header set with the value of eTag,
     * provided none of the precondition evaluation has failed, in which case the ETag header would not be included and the
     * status code of the returned {@code ResponseBuilder} would be set to {@link Response.Status#PRECONDITION_FAILED}.
     * @throws java.lang.IllegalArgumentException if lastModified or eTag is {@code null}.
     * @throws java.lang.IllegalStateException if called outside the scope of a request.
     */
    public ResponseBuilder evaluatePreconditions(Date lastModified, EntityTag eTag);

    
Evaluate request preconditions for a resource that does not currently exist. The primary use of this method is to
support the  If-Match: * and
 If-None-Match: * preconditions.

 Note that both preconditions If-None-Match: * and If-None-Match: something will always be considered to have been met and it is the applications responsibility to enforce any additional method-specific semantics. E.g. a PUT on a resource that does not exist might succeed whereas a GET on a resource that does not exist would likely result in a 404 response. It would be the responsibility of the application to generate the 404 response. 


Throws:
Returns:null if the preconditions are met or a ResponseBuilder set with the appropriate status if the preconditions are not met.
Since:1.1
/**
     * Evaluate request preconditions for a resource that does not currently exist. The primary use of this method is to
     * support the <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.24"> If-Match: *</a> and
     * <a href="http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.26"> If-None-Match: *</a> preconditions.
     *
     * <p>
     * Note that both preconditions {@code If-None-Match: *} and <code>If-None-Match: <i>something</i></code> will always be
     * considered to have been met and it is the applications responsibility to enforce any additional method-specific
     * semantics. E.g. a {@code PUT} on a resource that does not exist might succeed whereas a {@code GET} on a resource
     * that does not exist would likely result in a 404 response. It would be the responsibility of the application to
     * generate the 404 response.
     * </p>
     *
     * @return {@code null} if the preconditions are met or a {@code ResponseBuilder} set with the appropriate status if the
     * preconditions are not met.
     * @throws IllegalStateException if called outside the scope of a request.
     * @since 1.1
     */
    public ResponseBuilder evaluatePreconditions();

}