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      1 /*
      2  * Copyright (C) 2009 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 com.android.quicksearchbox.util.QuietlyCloseable;
     19 
     20 import android.database.DataSetObserver;
     21 
     22 import java.util.Collection;
     23 
     24 /**
     25  * A sequence of suggestions, with a current position.
     26  */
     27 public interface SuggestionCursor extends Suggestion, QuietlyCloseable {
     28 
     29     /**
     30      * Gets the query that the user typed to get this suggestion.
     31      */
     32     String getUserQuery();
     33 
     34     /**
     35      * Gets the number of suggestions in this result.
     36      *
     37      * @return The number of suggestions, or {@code 0} if this result represents a failed query.
     38      */
     39     int getCount();
     40 
     41     /**
     42      * Moves to a given suggestion.
     43      *
     44      * @param pos The position to move to.
     45      * @throws IndexOutOfBoundsException if {@code pos < 0} or {@code pos >= getCount()}.
     46      */
     47     void moveTo(int pos);
     48 
     49     /**
     50      * Moves to the next suggestion, if there is one.
     51      *
     52      * @return {@code false} if there is no next suggestion.
     53      */
     54     boolean moveToNext();
     55 
     56     /**
     57      * Gets the current position within the cursor.
     58      */
     59     int getPosition();
     60 
     61     /**
     62      * Frees any resources used by this cursor.
     63      */
     64     @Override
     65     void close();
     66 
     67     /**
     68      * Register an observer that is called when changes happen to this data set.
     69      *
     70      * @param observer gets notified when the data set changes.
     71      */
     72     void registerDataSetObserver(DataSetObserver observer);
     73 
     74     /**
     75      * Unregister an observer that has previously been registered with
     76      * {@link #registerDataSetObserver(DataSetObserver)}
     77      *
     78      * @param observer the observer to unregister.
     79      */
     80     void unregisterDataSetObserver(DataSetObserver observer);
     81 
     82     /**
     83      * Return the extra columns present in this cursor, or null if none exist.
     84      */
     85     Collection<String> getExtraColumns();
     86 }
     87