BaseBooleanSubscriber.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.datasource;

/**
 * Base implementation of {@link DataSubscriber} that ensures that the data source is closed when
 * the subscriber has finished with it.
 * <p>
 * Sample usage:
 * <pre>
 * <code>
 * imagePipeline.isInDiskCache(
 * uri,
 * new BaseBooleanSubscriber() {
 *   public void onNewResultImpl(boolean isFound) {
 *     // caller's code here
 *   }
 * });
 * </code>
 * </pre>
 */
public abstract class BaseBooleanSubscriber implements DataSubscriber<Boolean>{
  @Override
  public void onNewResult(DataSource<Boolean> dataSource) {
    try {
      onNewResultImpl(dataSource.getResult());
    } finally {
      dataSource.close();
    }
  }

  @Override
  public void onFailure(DataSource<Boolean> dataSource) {
    try {
      onFailureImpl(dataSource);
    } finally {
      dataSource.close();
    }
  }

  @Override
  public void onCancellation(DataSource<Boolean> dataSource) {
  }

  @Override
  public void onProgressUpdate(DataSource<Boolean> dataSource) {
  }

  protected abstract void onNewResultImpl(boolean isFoundInDisk);

  protected abstract void onFailureImpl(DataSource<Boolean> dataSource);
}