library/src/main/java/com/bumptech/glide/request/FutureTarget.java

package com.bumptech.glide.request;

import com.bumptech.glide.request.target.Target;

import java.util.concurrent.Future;

/**
 * An interface for an object that is both a {@link com.bumptech.glide.request.target.Target} and a
 * {@link java.util.concurrent.Future}. For example:
 * <pre>
 * {@code
 * FutureTarget<Bitmap> futureTarget = Glide.with(fragment)
 *                                       .load("http://goo.gl/1asf12")
 *                                       .asBitmap()
 *                                       .into(250, 250);
 * Bitmap myBitmap = futureTarget.get();
 * ... // do things with bitmap and then release when finished:
 * Glide.clear(futureTarget);
 * }
 * </pre>
 *
 * <p>
 *     Note - {@link #get()} and {@link #get(long, java.util.concurrent.TimeUnit)} must be called
 *     off of the main thread or they will block forever.
 * </p>
 *
 * @param <R> The type of resource this FutureTarget will retrieve.
 */
public interface FutureTarget<R> extends Future<R>, Target<R>  {

    /**
     * Safely clears the target from a background thread to release its resources.
     */
    void clear();
}