ValueFuture.java

package io.trane.future;

import java.time.Duration;
import java.util.function.BiFunction;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.logging.Level;
import java.util.logging.Logger;

final class ValueFuture<T> implements SatisfiedFuture<T> {

  private static final Logger logger = Logger.getLogger(ExceptionFuture.class.getName());

  final T value;

  protected ValueFuture(final T value) {
    this.value = value;
  }

  @Override
  public final <R> Future<R> map(final Function<? super T, ? extends R> f) {
    try {
      return new ValueFuture<>(f.apply(value));
    } catch (final Throwable ex) {
      return new ExceptionFuture<>(ex);
    }
  }

  @Override
  public final <R> Future<R> flatMap(final Function<? super T, ? extends Future<R>> f) {
    try {
      return f.apply(value);
    } catch (final Throwable ex) {
      return new ExceptionFuture<>(ex);
    }
  }

  @Override
  public <R> Future<R> transform(final Transformer<? super T, ? extends R> t) {
    try {
      return new ValueFuture<>(t.onValue(value));
    } catch (final Throwable ex) {
      return new ExceptionFuture<>(ex);
    }
  }

  @Override
  public <R> Future<R> transformWith(final Transformer<? super T, ? extends Future<R>> t) {
    try {
      return t.onValue(value);
    } catch (final Throwable ex) {
      return new ExceptionFuture<>(ex);
    }
  }

  @Override
  public <U, R> Future<R> biMap(final Future<U> other, final BiFunction<? super T, ? super U, ? extends R> f) {
    return other.map(u -> f.apply(value, u));
  }

  @Override
  public <U, R> Future<R> biFlatMap(final Future<U> other,
      final BiFunction<? super T, ? super U, ? extends Future<R>> f) {
    return other.flatMap(u -> f.apply(value, u));
  }

  @Override
  public final Future<T> onSuccess(final Consumer<? super T> c) {
    try {
      c.accept(value);
    } catch (final Throwable ex) {
      logger.log(Level.WARNING, "Error executing `onSuccess` callback " + c + "for" + this, ex);
      NonFatalException.verify(ex);
    }
    return this;
  }

  @Override
  public final Future<T> onFailure(final Consumer<Throwable> c) {
    return this;
  }

  @Override
  public final Future<T> respond(final Responder<? super T> r) {
    try {
      r.onValue(value);
    } catch (final Throwable ex) {
      logger.log(Level.WARNING, "Error when executing `respond` callback " + r + "for" + this, ex);
      NonFatalException.verify(ex);
    }
    return this;
  }

  @Override
  public final Future<T> rescue(final Function<Throwable, ? extends Future<T>> f) {
    return this;
  }

  @Override
  public final Future<Void> voided() {
    return VOID;
  }

  @Override
  public final T get(final Duration timeout) {
    return value;
  }

  @Override
  public final String toString() {
    return String.format("ValueFuture(%s)", value);
  }

  @Override
  public final int hashCode() {
    return (value == null) ? 0 : value.hashCode();
  }

  @Override
  public final boolean equals(final Object obj) {
    if (this == obj)
      return true;
    if (obj == null)
      return false;
    if (getClass() != obj.getClass())
      return false;
    final ValueFuture<?> other = (ValueFuture<?>) obj;
    if (value == null) {
      if (other.value != null)
        return false;
    } else if (!value.equals(other.value))
      return false;
    return true;
  }
}