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Mobius Core Library

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/*
 * -\-\-
 * Mobius
 * --
 * Copyright (c) 2017-2018 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;

import static com.spotify.mobius.internal_util.Preconditions.checkNotNull;

import com.spotify.mobius.disposables.Disposable;
import com.spotify.mobius.functions.Consumer;
import com.spotify.mobius.runners.WorkRunner;
import javax.annotation.Nonnull;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Dispatches messages to a given runner.
 *
 * @param  message type (typically a model, event, or effect descriptor type)
 */
class MessageDispatcher implements Consumer, Disposable {

  private static final Logger LOGGER = LoggerFactory.getLogger(MessageDispatcher.class);

  @Nonnull private final WorkRunner runner;
  @Nonnull private final Consumer consumer;

  private volatile boolean disabled = false;

  MessageDispatcher(WorkRunner runner, Consumer consumer) {
    this.runner = checkNotNull(runner);
    this.consumer = checkNotNull(consumer);
  }

  @Override
  public void accept(final M message) {
    runner.post(
        new Runnable() {
          @Override
          public void run() {
            if (disabled) {
              LOGGER.warn("Message ignored because the dispatcher is disabled: {}", message);

            } else {
              try {
                consumer.accept(message);

              } catch (Throwable throwable) {
                LOGGER.error(
                    "Consumer threw an exception when accepting message: {}", message, throwable);
              }
            }
          }
        });
  }

  @Override
  public void dispose() {
    runner.dispose();
  }

  void disable() {
    disabled = true;
  }
}