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;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;


Binds the value(s) of a HTTP header to a resource method parameter, resource class field, or resource class bean property. A default value can be specified using the DefaultValue annotation. The type T of the annotated parameter, field or property must either: 
    

  1. Be a primitive type
    2. 

  2. Have a constructor that accepts a single String argument
    3. 

  3. Have a static method named valueOf or fromString that accepts a single String argument (see, for example, Integer.valueOf(String))
    4. 

  4. Have a registered implementation of ParamConverterProvider JAX-RS extension SPI that returns a ParamConverter instance capable of a "from string" conversion for the type.
    5. 

  5. Be List<T>, Set<T> or SortedSet<T>, where T satisfies 2, 3 or 4 above. The resulting collection is read-only.
    6. 




If the type is not one of the collection types listed in 5 above and the header parameter is represented by multiple
values then the first value (lexically) of the parameter is used.




Because injection occurs at object creation time, use of this annotation on resource class fields and bean properties
is only supported for the default per-request resource class lifecycle. Resource classes using other lifecycles
should only use this annotation on resource method parameters.



Author:Paul Sandoz, Marc Hadley
See Also:
Since:1.0
/**
 * Binds the value(s) of a HTTP header to a resource method parameter, resource class field, or resource class bean
 * property. A default value can be specified using the {@link DefaultValue} annotation.
 *
 * The type {@code T} of the annotated parameter, field or property must either:
 * <ol>
 * <li>Be a primitive type</li>
 * <li>Have a constructor that accepts a single {@code String} argument</li>
 * <li>Have a static method named {@code valueOf} or {@code fromString} that accepts a single {@code String} argument
 * (see, for example, {@link Integer#valueOf(String)})</li>
 * <li>Have a registered implementation of {@link jakarta.ws.rs.ext.ParamConverterProvider} JAX-RS extension SPI that
 * returns a {@link jakarta.ws.rs.ext.ParamConverter} instance capable of a "from string" conversion for the type.</li>
 * <li>Be {@code List<T>}, {@code Set<T>} or {@code SortedSet<T>}, where {@code T} satisfies 2, 3 or 4 above. The
 * resulting collection is read-only.</li>
 * </ol>
 *
 * <p>
 * If the type is not one of the collection types listed in 5 above and the header parameter is represented by multiple
 * values then the first value (lexically) of the parameter is used.
 * </p>
 *
 * <p>
 * Because injection occurs at object creation time, use of this annotation on resource class fields and bean properties
 * is only supported for the default per-request resource class lifecycle. Resource classes using other lifecycles
 * should only use this annotation on resource method parameters.
 * </p>
 *
 * @author Paul Sandoz
 * @author Marc Hadley
 * @see DefaultValue
 * @see jakarta.ws.rs.core.HttpHeaders
 * @since 1.0
 */
@Target({ ElementType.PARAMETER, ElementType.METHOD, ElementType.FIELD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface HeaderParam {

    
Defines the name of the HTTP header whose value will be used to initialize the value of the annotated method
argument, class field or bean property. Case insensitive.

Returns:HTTP header name.
/**
     * Defines the name of the HTTP header whose value will be used to initialize the value of the annotated method
     * argument, class field or bean property. Case insensitive.
     *
     * @return HTTP header name.
     */
    String value();
}