Pair.java

import android.support.annotation.Nullable;

import com.google.auto.value.AutoValue;

/**
 * Copied from {@link android.support.v4.util.Pair} to remove all @Nullable annotations.
 * <p>
 * Container to ease passing around a tuple of two objects.
 */
public abstract class Pair<F, S> {

  public abstract F first();

  public abstract S second();

  public static <A, B> Pair<A, B> create(A first, B second) {
    return new AutoValue_Pair_NonNullPair<>(first, second);
  }

  public static <A, B> Pair<A, B> createNullable(@Nullable A first, @Nullable B second) {
    return new AutoValue_Pair_NullablePair<>(first, second);
  }

  @AutoValue
  abstract static class NonNullPair<F, S> extends Pair<F, S> {
    public abstract F first();

    public abstract S second();
  }

  @AutoValue
  abstract static class NullablePair<F, S> extends Pair<F, S> {
    @Nullable
    public abstract F first();

    @Nullable
    public abstract S second();
  }
}