com.spotify.flo.context.PrintUtils Maven / Gradle / Ivy

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/*-
 * -\-\-
 * flo runner
 * --
 * Copyright (C) 2016 Spotify AB
 * --
 * 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
 * 
 *      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 com.spotify.flo.context;

import static java.util.stream.Collectors.joining;

import com.spotify.flo.TaskId;
import com.spotify.flo.TaskInfo;
import java.util.ArrayList;
import java.util.List;
import java.util.Stack;
import java.util.function.BiConsumer;

/**
 * Utilities for printing the task tree
 */
final class PrintUtils {

  private PrintUtils() {
  }

  static List tree(TaskInfo taskInfo) {
    final List lines = new ArrayList<>();
    traverseTree(taskInfo, (taskId, s) -> lines.add(s));
    return lines;
  }

  static void traverseTree(TaskInfo taskInfo, BiConsumer consumer) {
    consumer.accept(taskInfo.id(), taskInfo.id().toString());
    popSubTree(taskInfo.inputs(), consumer, new Stack<>());
  }

  private static void popSubTree(List inputs, BiConsumer consumer, Stack indents) {
    for (int i = 0; i < inputs.size(); i++) {
      final TaskInfo taskInfo = inputs.get(i);
      final String indent = indents.stream()
          .map(b -> b ? "   " : "│  ")
          .collect(joining());
      final String branch = (i < inputs.size() - 1) ? "├" : "└";
      final String prefix = indent + branch + "▸ ";
      final String refArrow = taskInfo.isReference()
          ? " ⤴"
          : "";

      consumer.accept(taskInfo.id(), prefix + taskInfo.id() + refArrow);

      indents.push(i == inputs.size() - 1);
      popSubTree(taskInfo.inputs(), consumer, indents);
      indents.pop();
    }
  }
}