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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.camera.processing.imagebackend;
     18 
     19 import java.util.Set;
     20 import java.util.concurrent.Executor;
     21 
     22 /**
     23  * The interface by which Task derived off of TaskImageContainer can describe
     24  * its task dependencies and manage its image references.
     25  *
     26  */
     27 public interface ImageTaskManager {
     28 
     29     /**
     30      * Spawns dependent tasks from internal implementation of set of tasks. If a
     31      * dependent task does NOT require the image reference, it should be passed
     32      * a null pointer as an image reference. In general, this method should be
     33      * called after the task has completed its own computations, but before it
     34      * has released its own image reference (via the releaseSemaphoreReference
     35      * call).
     36      *
     37      * @param tasks The set of tasks to be run
     38      * @return whether tasks are successfully submitted.
     39      */
     40     public boolean appendTasks(ImageToProcess img, Set<TaskImageContainer> tasks);
     41 
     42     /**
     43      * Spawns a single dependent task from internal implementation of a task.
     44      *
     45      * @param task The task to be run
     46      * @return whether tasks are successfully submitted.
     47      */
     48     public boolean appendTasks(ImageToProcess img, TaskImageContainer task);
     49 
     50     /**
     51      * Signals the ImageTaskManager that a task has released a reference to the
     52      * image. ImageTaskManager determines whether all references have been
     53      * released and applies its specified release protocol of closing image
     54      * and/or unblocking the caller. Should ONLY be called by the tasks running
     55      * on this manager.
     56      *
     57      * @param img the image to be released by the task.
     58      * @param executor the executor on which the image close is run. if null,
     59      *            image close is run by the calling thread (usually the main
     60      *            task thread).
     61      */
     62     public void releaseSemaphoreReference(final ImageToProcess img, Executor executor);
     63 
     64     /**
     65      * Simple getter for the associated listener object associated with this
     66      * instance that handles registration of event listeners.
     67      *
     68      * @return listener proxy that handles events messaging for this object.
     69      */
     70     public ImageProcessorProxyListener getProxyListener();
     71 }
     72