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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.one.v2.core;
     18 
     19 import android.hardware.camera2.CameraAccessException;
     20 
     21 import com.android.camera.async.SafeCloseable;
     22 import com.android.camera.one.v2.camera2proxy.CameraCaptureSessionClosedException;
     23 
     24 import java.util.List;
     25 
     26 import javax.annotation.Nonnull;
     27 import javax.annotation.Nullable;
     28 import javax.annotation.concurrent.ThreadSafe;
     29 
     30 /**
     31  * Provides thread-safe access to a camera.
     32  */
     33 @ThreadSafe
     34 public interface FrameServer {
     35     /**
     36      * A Session enables submitting multiple Requests for frames.
     37      */
     38     @ThreadSafe
     39     public interface Session extends SafeCloseable {
     40         /**
     41          * Submits the given request, blocking until resources are allocated for
     42          * the request.
     43          *
     44          * @param burstRequests The request to submit to the camera device.
     45          * @throws java.lang.InterruptedException if interrupted before the
     46          *             request is be submitted.
     47          */
     48         public void submitRequest(List<Request> burstRequests, RequestType type)
     49                 throws CameraAccessException, InterruptedException,
     50                 CameraCaptureSessionClosedException, ResourceAcquisitionFailedException;
     51 
     52         @Override
     53         public void close();
     54     }
     55 
     56     /**
     57      * Indicates that a session has been closed already, via
     58      * {@link FrameServer.Session#close} and no more requests may be submitted.
     59      */
     60     public static class SessionClosedException extends RuntimeException {
     61     }
     62 
     63     public static enum RequestType {
     64         REPEATING, NON_REPEATING
     65     }
     66 
     67     /**
     68      * Creates an exclusive session. Blocks, if necessary, until any existing
     69      * exclusive session is closed.
     70      *
     71      * @return A new session which may be used to interact with the underlying
     72      *         camera.
     73      */
     74     @Nonnull
     75     public Session createExclusiveSession() throws InterruptedException;
     76 
     77     /**
     78      * Like {@link #createExclusiveSession}, but returns null instead of
     79      * blocking if the session cannot be created immediately.
     80      */
     81     @Nullable
     82     public Session tryCreateExclusiveSession();
     83 }
     84