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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.data;
     18 
     19 import android.net.Uri;
     20 
     21 import java.util.Collections;
     22 import java.util.Comparator;
     23 import java.util.HashMap;
     24 import java.util.LinkedList;
     25 
     26 /**
     27  * Fast access data structure for an ordered LocalData list.
     28  */
     29 public class LocalDataList {
     30     /**
     31      * We use this as a way to compare a Uri to LocalData instances inside a
     32      * LinkedList. A linked list in indexOf does a other.equals(get(i)).
     33      */
     34     private static class UriWrapper {
     35         private final Uri mUri;
     36 
     37         public UriWrapper(Uri uri) {
     38             mUri = uri;
     39         }
     40 
     41         @Override
     42         public boolean equals(Object o) {
     43             if (!(o instanceof LocalData)) {
     44                 return false;
     45             }
     46             return mUri.equals(((LocalData) o).getContentUri());
     47         }
     48     }
     49 
     50     private LinkedList<LocalData> mList = new LinkedList<LocalData>();
     51     private HashMap<Uri, LocalData> mUriMap = new HashMap<Uri, LocalData>();
     52 
     53     public LocalData get(int index) {
     54         return mList.get(index);
     55     }
     56 
     57     public LocalData remove(int index) {
     58         LocalData removedItem = mList.remove(index);
     59         mUriMap.remove(removedItem);
     60         return removedItem;
     61     }
     62 
     63     public LocalData get(Uri uri) {
     64         return mUriMap.get(uri);
     65     }
     66 
     67     public void set(int pos, LocalData data) {
     68         mList.set(pos, data);
     69         mUriMap.put(data.getContentUri(), data);
     70     }
     71 
     72     public void add(LocalData data) {
     73         mList.add(data);
     74         mUriMap.put(data.getContentUri(), data);
     75     }
     76 
     77     public void add(int pos, LocalData data) {
     78         mList.add(pos, data);
     79         mUriMap.put(data.getContentUri(), data);
     80     }
     81 
     82     public int size() {
     83         return mList.size();
     84     }
     85 
     86     public void sort(Comparator<LocalData> comparator) {
     87         Collections.sort(mList, comparator);
     88     }
     89 
     90     /**
     91      * This implementation routes through to LinkedList.indexOf, so performs in
     92      * O(n) but has a fast exit path for when the uri is not contained in the
     93      * list, and immediately returns -1;
     94      */
     95     public int indexOf(Uri uri) {
     96         if (!mUriMap.containsKey(uri)) {
     97             return -1;
     98         }
     99         return mList.indexOf(new UriWrapper(uri));
    100     }
    101 }
    102