juneau-rest/juneau-rest-client/src/main/java/org/apache/juneau/rest/client/RetryOn.java

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package org.apache.juneau.rest.client;

import org.apache.http.*;

/**
 * Used to determine whether a request should be retried based on the HTTP response code.
 *
 * <p>
 * Subclasses should override either the {@link #onCode(int)} method (if you only care about the HTTP status code)
 * or {@link #onResponse(HttpResponse)} (if you want full access to the HTTP response object.
 */
public abstract class RetryOn {

	/**
	 * Default RetryOn that returns <jk>true</jk> of any HTTP response &gt;= 400 is received.
	 */
	public static final RetryOn DEFAULT = new RetryOn() {
		@Override /* RetryOn */
		public boolean onCode(int httpResponseCode) {
			return httpResponseCode <= 0 || httpResponseCode >= 400;
		}
	};

	/**
	 * Default RetryOn that returns <jk>true</jk> if the HTTP connection could not be made.
	 */
	public static final RetryOn CONNECTION_LOST = new RetryOn() {
		@Override /* RetryOn */
		public boolean onCode(int httpResponseCode) {
			return httpResponseCode <= 0;
		}
	};

	/**
	 * Subclasses should override this method to determine whether the HTTP response is retryable.
	 *
	 * @param response The HTTP response object.  May be <jk>null</jk> if a connection could not be made.
	 * @return <jk>true</jk> if the specified response code is retryable.
	 */
	protected boolean onResponse(HttpResponse response) {
		return onCode(response == null || response.getStatusLine() == null ? -1 : response.getStatusLine().getStatusCode());
	}

	/**
	 * Subclasses should override this method to determine whether the HTTP response is retryable.
	 *
	 * @param httpResponseCode The HTTP response code.  <c>-1</c> if a connection could not be made.
	 * @return <jk>true</jk> if the specified response code is retryable.
	 */
	protected boolean onCode(int httpResponseCode) {
		return false;
	}
}