}

  @Override
  public C first() {
    // requireNonNull is safe because we checked the range is not empty in ContiguousSet.create.
    return requireNonNull(range.lowerBound.leastValueAbove(domain));
  }

  @Override
  public C last() {
    // requireNonNull is safe because we checked the range is not empty in ContiguousSet.create.
    return requireNonNull(range.upperBound.greatestValueBelow(domain));
  }

 */

package com.google.common.graph;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;
import static java.util.Objects.requireNonNull;

import java.util.Collections;
import java.util.Map;
import java.util.Set;
import javax.annotation.CheckForNull;

/**
 * A base implementation of {@link NetworkConnections} for undirected networks.
 *

      C columnKey = cell.getColumnKey();
      V value = cell.getValue();

      /*
       * These requireNonNull calls are safe because we construct the maps to hold all the provided
       * cells.
       */
      cellRowIndices[i] = requireNonNull(rowIndex.get(rowKey));
      Map<C, V> thisRow = requireNonNull(rows.get(rowKey));
      cellColumnInRowIndices[i] = thisRow.size();
      V oldValue = thisRow.put(columnKey, value);

    }
  }

  private boolean hasRemaining() {
    return remaining() > 0;
  }

  private int remaining() {
    requireNonNull(seq); // safe as long as we call this only after checkOpen
    return seq.length() - pos;
  }

  /*
   * To avoid the need to call requireNonNull so much, we could consider more clever approaches,
   * such as:
   *

    }
  }

  private boolean hasRemaining() {
    return remaining() > 0;
  }

  private int remaining() {
    requireNonNull(seq); // safe as long as we call this only after checkOpen
    return seq.length() - pos;
  }

  /*
   * To avoid the need to call requireNonNull so much, we could consider more clever approaches,
   * such as:
   *

          submittingTaskQueue.nextTask = task;
          // requireNonNull(delegate) is safe for reasons similar to requireNonNull(sequencer).
          submittingTaskQueue.nextExecutor = requireNonNull(delegate);
          delegate = null;
        } else {
          // requireNonNull(delegate) is safe for reasons similar to requireNonNull(sequencer).
          Executor localDelegate = requireNonNull(delegate);
          delegate = null;

    // be deleted.
    Map<K, @Nullable V> duplicates = null;
    int dupCount = 0;
    for (int i = 0; i < n; i++) {
      // requireNonNull is safe because the first `n` elements have been filled in.
      entryArray[i] = makeImmutable(requireNonNull(entryArray[i]));
      K key = entryArray[i].getKey();
      V value = entryArray[i].getValue();
      V oldValue = delegateMap.put(key, value);

    public Metadata read(File input, Map<String, ?> options) throws IOException {
        Objects.requireNonNull(input, "input cannot be null");

        return read(Files.newInputStream(input.toPath()), options);
    }

    public Metadata read(Reader input, Map<String, ?> options) throws IOException {
        Objects.requireNonNull(input, "input cannot be null");

        try (Reader in = input) {

        return modelIds;
    }

    public DefaultModelBuildingResult addModelId(String modelId) {
        // Intentionally notNull because Super POM may not contain a modelId
        Objects.requireNonNull(modelId, "modelId cannot null");

        modelIds.add(modelId);

        return this;
    }

    @Override
    public Model getRawModel() {
        return rawModels.get(modelIds.get(0));

    // requireNonNull is safe because we use indexes that were populated by the constructor.
    V value = requireNonNull(values[rowIndex][columnIndex]);
    return cellOf(rowKey, columnKey, value);
  }

  @Override
  V getValue(int index) {
    // requireNonNull is safe because we use indexes that were populated by the constructor.