content: /*
   * Copyright 2010 Proofpoint, Inc.
   *
   * 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 io.airlift.bootstrap;
  
  import com.google.common.collect.ImmutableList;
  
  import java.util.ArrayList;
  import java.util.Arrays;
  import java.util.Collection;
  import java.util.LinkedHashSet;
  import java.util.List;
  
  import static com.google.common.base.Preconditions.checkArgument;
  import static com.google.common.base.Strings.repeat;
  import static java.lang.Math.max;
  import static java.util.stream.Collectors.toCollection;
  
  /**
   * A utility for outputting columnar text
   */
  class ColumnPrinter
  {
      private static final int DEFAULT_MARGIN = 2;
  
      private final Collection<List<String>> data = new LinkedHashSet<>();
      private final List<String> columnNames;
      private final List<Integer> columnWidths;
      private final int margin;
  
      public ColumnPrinter(String... columnNames)
      {
          this(DEFAULT_MARGIN, columnNames);
      }
  
      public ColumnPrinter(int margin, String... columnNames)
      {
          this.margin = margin;
          this.columnNames = ImmutableList.copyOf(columnNames);
          this.columnWidths = Arrays.stream(columnNames)
                  .map(String::length)
                  .collect(toCollection(ArrayList::new));
      }
  
      public void addValues(String... values)
      {
          checkArgument(values.length == columnNames.size(), "wrong value count");
          for (int i = 0; i < values.length; i++) {
              columnWidths.set(i, max(values[i].length(), columnWidths.get(i)));
          }
          data.add(ImmutableList.copyOf(values));
      }
  
      public List<String> generateOutput()
      {
          List<String> lines = new ArrayList<>();
          lines.add(printRow(columnNames));
          for (List<String> row : data) {
              lines.add(printRow(row));
          }
          return lines;
      }
  
      private String printRow(List<String> values)
      {
          StringBuilder sb = new StringBuilder();
          for (int i = 0; i < values.size(); i++) {
              sb.append(value(values.get(i), columnWidths.get(i) + margin));
          }
          return sb.toString().trim();
      }
  
      private static String value(String value, int width)
      {
          return value + repeat(" ", width - value.length());
      }
  }
  