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      1 /*
      2  * Copyright (C) 2013 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.app;
     18 
     19 import java.util.HashMap;
     20 
     21 /**
     22  * Keeps track of memory used by the app and informs modules and services if
     23  * memory gets low.
     24  */
     25 public interface MemoryManager {
     26     /**
     27      * Classes implementing this interface will be able to get updates about
     28      * memory status changes.
     29      */
     30     public static interface MemoryListener {
     31         /**
     32          * Called when the app is experiencing a change in memory state. Modules
     33          * should listen to these to not exceed the available memory.
     34          *
     35          * @param state the new state, one of {@link MemoryManager#STATE_OK},
     36          *            {@link MemoryManager#STATE_LOW_MEMORY},
     37          */
     38         public void onMemoryStateChanged(int state);
     39 
     40         /**
     41          * Called when the system is about to kill our app due to high memory
     42          * load.
     43          */
     44         public void onLowMemory();
     45     }
     46 
     47     /** The memory status is OK. The app can function as normal. */
     48     public static final int STATE_OK = 0;
     49 
     50     /** The memory is running low. E.g. no new media should be captured. */
     51     public static final int STATE_LOW_MEMORY = 1;
     52 
     53     /**
     54      * Add a new listener that is informed about upcoming memory events.
     55      */
     56     public void addListener(MemoryListener listener);
     57 
     58     /**
     59      * Removes an already registered listener.
     60      */
     61     public void removeListener(MemoryListener listener);
     62 
     63     /**
     64      * Returns the maximum amount of memory allowed to be allocated in native
     65      * code by our app (in megabytes).
     66      */
     67     public int getMaxAllowedNativeMemoryAllocation();
     68 
     69     /**
     70      * Queries the memory consumed, total memory, and memory thresholds for this app.
     71      *
     72      * @return HashMap containing memory metrics keyed by string labels
     73      *     defined in {@link MemoryQuery}.
     74      */
     75     public HashMap queryMemory();
     76 }
     77