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      1 /*
      2  * Copyright (C) 2010 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 package com.android.quicksearchbox;
     17 
     18 import android.database.Cursor;
     19 import android.util.Log;
     20 
     21 import java.util.ArrayList;
     22 import java.util.Arrays;
     23 import java.util.HashSet;
     24 import java.util.List;
     25 
     26 /**
     27  * SuggestionExtras taking values from the extra columns in a suggestion cursor.
     28  */
     29 public class CursorBackedSuggestionExtras extends AbstractSuggestionExtras {
     30     private static final String TAG = "QSB.CursorBackedSuggestionExtras";
     31 
     32     private static final HashSet<String> DEFAULT_COLUMNS = new HashSet<String>();
     33     static {
     34         DEFAULT_COLUMNS.addAll(Arrays.asList(SuggestionCursorBackedCursor.COLUMNS));
     35     }
     36 
     37     private final Cursor mCursor;
     38     private final int mCursorPosition;
     39     private final List<String> mExtraColumns;
     40 
     41     static CursorBackedSuggestionExtras createExtrasIfNecessary(Cursor cursor, int position) {
     42         List<String> extraColumns = getExtraColumns(cursor);
     43         if (extraColumns != null) {
     44             return new CursorBackedSuggestionExtras(cursor, position, extraColumns);
     45         } else {
     46             return null;
     47         }
     48     }
     49 
     50     static String[] getCursorColumns(Cursor cursor) {
     51         try {
     52             return cursor.getColumnNames();
     53         } catch (RuntimeException ex) {
     54             // all operations on cross-process cursors can throw random exceptions
     55             Log.e(TAG, "getColumnNames() failed, ", ex);
     56             return null;
     57         }
     58     }
     59 
     60     static boolean cursorContainsExtras(Cursor cursor) {
     61         String[] columns = getCursorColumns(cursor);
     62         for (String cursorColumn : columns) {
     63             if (!DEFAULT_COLUMNS.contains(cursorColumn)) {
     64                 return true;
     65             }
     66         }
     67         return false;
     68     }
     69 
     70     static List<String> getExtraColumns(Cursor cursor) {
     71         String[] columns = getCursorColumns(cursor);
     72         if (columns == null) return null;
     73         List<String> extraColumns = null;
     74         for (String cursorColumn : columns) {
     75             if (!DEFAULT_COLUMNS.contains(cursorColumn)) {
     76                 if (extraColumns == null) {
     77                     extraColumns = new ArrayList<String>();
     78                 }
     79                 extraColumns.add(cursorColumn);
     80             }
     81         }
     82         return extraColumns;
     83     }
     84 
     85     private CursorBackedSuggestionExtras(Cursor cursor, int position, List<String> extraColumns) {
     86         super(null);
     87         mCursor = cursor;
     88         mCursorPosition = position;
     89         mExtraColumns = extraColumns;
     90     }
     91 
     92     @Override
     93     public String doGetExtra(String columnName) {
     94         try {
     95             mCursor.moveToPosition(mCursorPosition);
     96             int columnIdx = mCursor.getColumnIndex(columnName);
     97             if (columnIdx < 0) return null;
     98             return mCursor.getString(columnIdx);
     99         } catch (RuntimeException ex) {
    100             // all operations on cross-process cursors can throw random exceptions
    101             Log.e(TAG, "getExtra(" + columnName + ") failed, ", ex);
    102             return null;
    103         }
    104     }
    105 
    106     @Override
    107     public List<String> doGetExtraColumnNames() {
    108         return mExtraColumns;
    109     }
    110 
    111 }
    112