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Async Flow based on Promise API
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/*
 *  Copyright 2022 Red Hat
 *
 *  Licensed 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
 *
 *      https://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.jboss.hal.flow;

import java.util.List;

import static org.jboss.hal.flow.SequenceImpl.Mode.PARALLEL;
import static org.jboss.hal.flow.SequenceImpl.Mode.SEQUENTIAL;

/**
 * An interface to execute a list of {@linkplain Task asynchronous tasks} in parallel or sequentially, or to execute a single
 * {@linkplain Task task} {@linkplain #repeat(FlowContext, Task) repeatedly} as long as certain conditions are met.
 * 
 * The {@linkplain Task tasks} share a {@linkplain FlowContext context} that can be used to store data in a map or on a stack.
 */
public interface Flow {

    /**
     * Executes a list of {@linkplain Task asynchronous tasks} in parallel (all at once).
     *
     * @param context the context shared between tasks
     * @param tasks the list of tasks to execute in parallel
     * @param  the type of the shared context
     * @return an interface to control whether the execution of the tasks should fail fast or fail last
     */
    static  Sequence parallel(C context, List> tasks) {
        return new SequenceImpl<>(PARALLEL, context, tasks);
    }

    /**
     * Executes a list of {@linkplain Task asynchronous tasks} in sequence (one after the other).
     *
     * @param context the context shared between tasks
     * @param tasks the list of tasks to execute in order
     * @param  the type of the shared context
     * @return an interface to control whether the execution of the tasks should fail fast or fail last
     */
    static  Sequence sequential(C context, List> tasks) {
        return new SequenceImpl<>(SEQUENTIAL, context, tasks);
    }

    /**
     * Executes the given {@linkplain Task task} repeatedly as long as the conditions defined by {@link Repeat} are met.
     *
     * @param context the context shared between the iterations
     * @param task the task to execute while the predicate evaluates to {@code true}
     * @param  the type of the shared context
     * @return an interface to control the interval, timeout and fail fast behaviour
     */
    static  Repeat repeat(C context, Task task) {
        return new RepeatImpl<>(context, task);
    }
}