com.spotify.mobius.extras.Program Maven / Gradle / Ivy

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/*
 * -\-\-
 * Mobius
 * --
 * Copyright (c) 2017-2020 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.mobius.extras;

import com.google.auto.value.AutoValue;
import com.spotify.mobius.Connectable;
import com.spotify.mobius.EventSource;
import com.spotify.mobius.Init;
import com.spotify.mobius.Mobius;
import com.spotify.mobius.MobiusLoop;
import com.spotify.mobius.Update;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;

/**
 * This class defines a Mobius program. It holds you your {@link Init}, {@link Update}, {@link
 * EventSource}, and {@link Connectable} definitions, as well as the tag you would like to use for
 * identifying your program in logs. It is primarily meant to be used for composing programs, in
 * most cases you should prefer to use {@link Mobius#loop(Update, Connectable)}.
 */
@AutoValue
public abstract class Program {

  @Nonnull
  public abstract Update update();

  @Nonnull
  public abstract Connectable effectHandler();

  @Nullable
  public abstract Init init();

  @Nullable
  public abstract EventSource eventSource();

  @Nullable
  public abstract String loggingTag();

  /** Returns a {@link MobiusLoop.Builder} based on this program */
  public MobiusLoop.Builder createLoop() {
    MobiusLoop.Builder builder = Mobius.loop(update(), effectHandler());

    Init init = init();
    if (init != null) {
      builder = builder.init(init);
    }

    EventSource eventSource = eventSource();
    if (eventSource != null) {
      builder = builder.eventSource(eventSource);
    }

    String loggingTag = loggingTag();
    if (loggingTag != null) {
      builder = builder.logger(SLF4JLogger.withTag(loggingTag));
    }

    return builder;
  }

  public static  Builder builder() {
    return new AutoValue_Program.Builder<>();
  }

  @AutoValue.Builder
  public abstract static class Builder {
    public abstract Builder update(Update update);

    public abstract Builder effectHandler(Connectable effectHandler);

    public abstract Builder init(Init init);

    public abstract Builder eventSource(EventSource eventSource);

    public abstract Builder loggingTag(String loggingTag);

    public abstract Program build();
  }
}