com.codepoetics.fluvius.api.Flow Maven / Gradle / Ivy

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package com.codepoetics.fluvius.api;

import com.codepoetics.fluvius.api.scratchpad.Key;

import java.io.Serializable;
import java.util.List;
import java.util.Set;
import java.util.UUID;

/**
 * A Flow which takes values from a Scratchpad, and provides a new value to be written into the Scratchpad.
 *
 * @param  The type of value returned by the flow.
 */
public interface Flow extends Serializable {

  /**
   * Get the unique identifier of this flow.
   * @return The unique identifier of this flow.
   */
  UUID getStepId();

  /**
   * Get the required Keys that this Flow expects to find in the Scratchpad.
   *
   * @return The required Keys that this Flow expects to find in the Scratchpad.
   */
  Set> getRequiredKeys();

  /**
   * Get the Key that this Flow will write into the Scratchpad.
   *
   * @return The key that this Flow will write into the Scratchpad.
   */
  Key getProvidedKey();

  /**
   * Convert this Flow into a value of some kind (e.g. an Action) by visiting it (and all of its sub-flows) with the supplied FlowVisitor.
   *
   * @param visitor The FlowVisitor to visit this Flow (and all of its sub-flows) with.
   * @param      The type of the value constructed by the FlowVisitor.
   * @return The value constructed by the FlowVisitor.
   */
   V visit(FlowVisitor visitor);

  /**
   * Combine this Flow with a subsequent Flow to create a sequence of Flows.
   *
   * @param next The Flow to run after this Flow.
   * @param   The type of value returned by the next Flow in the sequence (and hence the type of the new sequence of Flows).
   * @return The constructed Flow.
   */
   Flow then(Flow next);

  /**
   * Create a branching Flow, with this Flow as the default branch and the supplied Condition and Flow as the first conditional branch.
   * If this Flow is already a branching Flow, then the supplied Condition and Flow are used to add another conditional branch to it.
   *
   * @param condition The Condition to test to determine whether to execute the supplied Flow.
   * @param ifTrue    The Flow to execute if the Condition is met.
   * @return The constructed Flow.
   */
  Flow orIf(Condition condition, Flow ifTrue);

  /**
   * Flatten this flow into a list of flows.
   * @return A list of flows containing either this flow, or (if this flow is a sequence) all of the flows in this flow.
   */
  List> getAllFlows();
}