ForwardingControllerListener.java

/*
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

package com.facebook.drawee.controller;

import javax.annotation.Nullable;
import javax.annotation.concurrent.ThreadSafe;

import java.util.List;

import android.graphics.drawable.Animatable;
import android.util.Log;

import com.facebook.common.internal.Lists;

/**
 * Listener that forwards controller events to multiple listeners.
 */
@ThreadSafe
public class ForwardingControllerListener<INFO> implements ControllerListener<INFO> {
  private static final String TAG = "ForwardingControllerListener";

  private final List<ControllerListener<? super INFO>> mListeners
      = Lists.newArrayListWithCapacity(2);

  public ForwardingControllerListener() {
  }

  public static <INFO> ForwardingControllerListener<INFO> create() {
    return new ForwardingControllerListener<INFO>();
  }

  public static <INFO> ForwardingControllerListener<INFO> of(
      ControllerListener<? super INFO> listener) {
    ForwardingControllerListener<INFO> forwarder = create();
    forwarder.addListener(listener);
    return forwarder;
  }

  public static <INFO> ForwardingControllerListener<INFO> of(
      ControllerListener<? super INFO> listener1,
      ControllerListener<? super INFO> listener2) {
    ForwardingControllerListener<INFO> forwarder = create();
    forwarder.addListener(listener1);
    forwarder.addListener(listener2);
    return forwarder;
  }

  public synchronized void addListener(ControllerListener<? super INFO> listener) {
    mListeners.add(listener);
  }

  public synchronized void removeListener(ControllerListener<? super INFO> listener) {
    mListeners.remove(listener);
  }

  public synchronized void clearListeners() {
    mListeners.clear();
  }

  private synchronized void onException(String message, Throwable t) {
    Log.e(TAG, message, t);
  }

  @Override
  public synchronized void onSubmit(String id, Object callerContext) {
    final int numberOfListeners = mListeners.size();
    for (int i = 0; i < numberOfListeners; ++i) {
      ControllerListener<? super INFO> listener = mListeners.get(i);
      try {
        listener.onSubmit(id, callerContext);
      } catch (Exception exception) {
        // Don't punish the other listeners if we're given a bad one.
        onException("InternalListener exception in onSubmit", exception);
      }
    }
  }

  @Override
  public synchronized void onFinalImageSet(
      String id,
      @Nullable INFO imageInfo,
      @Nullable Animatable animatable) {
    final int numberOfListeners = mListeners.size();
    for (int i = 0; i < numberOfListeners; ++i) {
      ControllerListener<? super INFO> listener = mListeners.get(i);
      try {
        listener.onFinalImageSet(id, imageInfo, animatable);
      } catch (Exception exception) {
        // Don't punish the other listeners if we're given a bad one.
        onException("InternalListener exception in onFinalImageSet", exception);
      }
    }
  }

  @Override
  public void onIntermediateImageSet(String id, @Nullable INFO imageInfo) {
    final int numberOfListeners = mListeners.size();
    for (int i = 0; i < numberOfListeners; ++i) {
      ControllerListener<? super INFO> listener = mListeners.get(i);
      try {
        listener.onIntermediateImageSet(id, imageInfo);
      } catch (Exception exception) {
        // Don't punish the other listeners if we're given a bad one.
        onException("InternalListener exception in onIntermediateImageSet", exception);
      }
    }
  }

  @Override
  public void onIntermediateImageFailed(String id, Throwable throwable) {
    final int numberOfListeners = mListeners.size();
    for (int i = 0; i < numberOfListeners; ++i) {
      ControllerListener<? super INFO> listener = mListeners.get(i);
      try {
        listener.onIntermediateImageFailed(id, throwable);
      } catch (Exception exception) {
        // Don't punish the other listeners if we're given a bad one.
        onException("InternalListener exception in onIntermediateImageFailed", exception);
      }
    }
  }

  @Override
  public synchronized void onFailure(String id, Throwable throwable) {
    final int numberOfListeners = mListeners.size();
    for (int i = 0; i < numberOfListeners; ++i) {
      ControllerListener<? super INFO> listener = mListeners.get(i);
      try {
        listener.onFailure(id, throwable);
      } catch (Exception exception) {
        // Don't punish the other listeners if we're given a bad one.
        onException("InternalListener exception in onFailure", exception);
      }
    }
  }

  @Override
  public synchronized void onRelease(String id) {
    final int numberOfListeners = mListeners.size();
    for (int i = 0; i < numberOfListeners; ++i) {
      ControllerListener<? super INFO> listener = mListeners.get(i);
      try {
        listener.onRelease(id);
      } catch (Exception exception) {
        // Don't punish the other listeners if we're given a bad one.
        onException("InternalListener exception in onRelease", exception);
      }
    }
  }
}