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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 com.android.camera.debug.Log;
     22 import com.android.camera.debug.Log.Tag;
     23 
     24 import java.util.Collections;
     25 import java.util.Comparator;
     26 import java.util.HashMap;
     27 import java.util.LinkedList;
     28 import java.util.List;
     29 
     30 /**
     31  * Fast access data structure for an ordered LocalData list.
     32  */
     33 public class FilmstripItemList {
     34     /**
     35      * We use this as a way to compare a Uri to LocalData instances inside a
     36      * LinkedList. A linked list in indexOf does a other.equals(get(i)).
     37      */
     38     private static class UriWrapper {
     39         private final Uri mUri;
     40 
     41         public UriWrapper(Uri uri) {
     42             mUri = uri;
     43         }
     44 
     45         @Override
     46         public boolean equals(Object o) {
     47             if (!(o instanceof FilmstripItem)) {
     48                 return false;
     49             }
     50             return mUri.equals(((FilmstripItem) o).getData().getUri());
     51         }
     52     }
     53 
     54     private static final Tag TAG = new Tag("LocalDataList");
     55     private final LinkedList<FilmstripItem> mList = new LinkedList<FilmstripItem>();
     56     private final HashMap<Uri, FilmstripItem> mUriMap = new HashMap<Uri, FilmstripItem>();
     57 
     58     public FilmstripItem get(int index) {
     59         return mList.get(index);
     60     }
     61 
     62     /**
     63      * Removes the item at the given index.
     64      *
     65      * @param index the item to delete
     66      * @return If the item was found and deleted, it is returned. If the item
     67      *         was not found, null is returned.
     68      */
     69     public synchronized FilmstripItem remove(int index) {
     70         try {
     71             FilmstripItem removedItem = mList.remove(index);
     72             mUriMap.remove(removedItem);
     73             return removedItem;
     74         } catch (IndexOutOfBoundsException ex) {
     75             Log.w(TAG, "Could not remove item. Not found: " + index, ex);
     76             return null;
     77         }
     78     }
     79 
     80     public FilmstripItem get(Uri uri) {
     81         return mUriMap.get(uri);
     82     }
     83 
     84     public void set(int pos, FilmstripItem data) {
     85         mList.set(pos, data);
     86         mUriMap.put(data.getData().getUri(), data);
     87     }
     88 
     89     public void add(FilmstripItem data) {
     90         mList.add(data);
     91         mUriMap.put(data.getData().getUri(), data);
     92     }
     93 
     94     public void add(int pos, FilmstripItem data) {
     95         mList.add(pos, data);
     96         mUriMap.put(data.getData().getUri(), data);
     97     }
     98 
     99     public void addAll(List<? extends FilmstripItem> filmstripItemList) {
    100         for (FilmstripItem filmstripItem : filmstripItemList) {
    101             add(filmstripItem);
    102         }
    103     }
    104 
    105     public int size() {
    106         return mList.size();
    107     }
    108 
    109     public void sort(Comparator<FilmstripItem> comparator) {
    110         Collections.sort(mList, comparator);
    111     }
    112 
    113     /**
    114      * This implementation routes through to LinkedList.indexOf, so performs in
    115      * O(n) but has a fast exit path for when the uri is not contained in the
    116      * list, and immediately returns -1;
    117      */
    118     public int indexOf(Uri uri) {
    119         if (!mUriMap.containsKey(uri)) {
    120             return -1;
    121         }
    122         return mList.indexOf(new UriWrapper(uri));
    123     }
    124 }
    125