/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.pulsar.client.impl.auth.oauth2;

import org.apache.pulsar.client.impl.auth.oauth2.protocol.TokenResult;
import java.io.Serializable;
import org.apache.pulsar.client.api.PulsarClientException;

/**
 * An OAuth 2.0 authorization flow.
 */
interface Flow extends Serializable, AutoCloseable {

    /**
     * Initializes the authorization flow.
     * @throws PulsarClientException if the flow could not be initialized.
     */
    void initialize() throws PulsarClientException;

    /**
     * Acquires an access token from the OAuth 2.0 authorization server.
     * @return a token result including an access token and optionally a refresh token.
     * @throws PulsarClientException if authentication failed.
     */
    TokenResult authenticate() throws PulsarClientException;

    /**
     * Closes the authorization flow.
     */
    void close() throws Exception;
}
