juneau-core/juneau-marshall/src/main/java/org/apache/juneau/http/header/MaxForwards.java

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package org.apache.juneau.http.header;

import java.util.function.*;

import org.apache.juneau.http.annotation.*;

/**
 * Represents a parsed <l>Max-Forwards</l> HTTP request header.
 *
 * <p>
 * Limit the number of times the message can be forwarded through proxies or gateways.
 *
 * <h5 class='figure'>Example</h5>
 * <p class='bcode w800'>
 * 	Max-Forwards: 10
 * </p>
 *
 * <h5 class='topic'>RFC2616 Specification</h5>
 *
 * The Max-Forwards request-header field provides a mechanism with the TRACE (section 9.8) and OPTIONS (section 9.2)
 * methods to limit the number of proxies or gateways that can forward the request to the next inbound server.
 * This can be useful when the client is attempting to trace a request chain which appears to be failing or looping in
 * mid-chain.
 *
 * <p class='bcode w800'>
 * 	Max-Forwards   = "Max-Forwards" ":" 1*DIGIT
 * </p>
 *
 * <p>
 * The Max-Forwards value is a decimal integer indicating the remaining number of times this request message may be
 * forwarded.
 *
 * <p>
 * Each proxy or gateway recipient of a TRACE or OPTIONS request containing a Max-Forwards header field MUST check and
 * update its value prior to forwarding the request.
 * If the received value is zero (0), the recipient MUST NOT forward the request; instead, it MUST respond as the final
 * recipient.
 * If the received Max-Forwards value is greater than zero, then the forwarded message MUST contain an updated
 * Max-Forwards field with a value decremented by one (1).
 *
 * <p>
 * The Max-Forwards header field MAY be ignored for all other methods defined by this specification and for any
 * extension methods for which it is not explicitly referred to as part of that method definition.
 *
 * <ul class='seealso'>
 * 	<li class='extlink'>{@doc ExtRFC2616}
 * </ul>
 */
@Header("Max-Forwards")
public class MaxForwards extends BasicIntegerHeader {

	private static final long serialVersionUID = 1L;
	private static final String NAME = "Max-Forwards";

	/**
	 * Convenience creator.
	 *
	 * @param value
	 * 	The header value.
	 * 	<br>Must be parsable using {@link Integer#parseInt(String)}.
	 * 	<br>Can be <jk>null</jk>.
	 * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
	 */
	public static MaxForwards of(String value) {
		if (value == null)
			return null;
		return new MaxForwards(value);
	}

	/**
	 * Convenience creator.
	 *
	 * @param value
	 * 	The header value.
	 * 	<br>Can be <jk>null</jk>.
	 * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
	 */
	public static MaxForwards of(Integer value) {
		if (value == null)
			return null;
		return new MaxForwards(value);
	}

	/**
	 * Convenience creator with delayed value.
	 *
	 * <p>
	 * Header value is re-evaluated on each call to {@link #getValue()}.
	 *
	 * @param value
	 * 	The supplier of the header value.
	 * 	<br>Can be <jk>null</jk>.
	 * @return A new header bean, or <jk>null</jk> if the value is <jk>null</jk>.
	 */
	public static MaxForwards of(Supplier<Integer> value) {
		if (value == null)
			return null;
		return new MaxForwards(value);
	}

	/**
	 * Constructor.
	 *
	 * @param value
	 * 	The header value.
	 * 	<br>Must be parsable using {@link Integer#parseInt(String)}.
	 * 	<br>Can be <jk>null</jk>.
	 */
	public MaxForwards(String value) {
		super(NAME, value);
	}

	/**
	 * Constructor.
	 *
	 * @param value
	 * 	The header value.
	 * 	<br>Can be <jk>null</jk>.
	 */
	public MaxForwards(Integer value) {
		super(NAME, value);
	}

	/**
	 * Constructor with delayed value.
	 *
	 * <p>
	 * Header value is re-evaluated on each call to {@link #getValue()}.
	 *
	 * @param value
	 * 	The supplier of the header value.
	 * 	<br>Can be <jk>null</jk>.
	 */
	public MaxForwards(Supplier<Integer> value) {
		super(NAME, value);
	}
}