SuggestionCursor.java revision 5229b06f00d20aac76cd8519b37f2a579d61c54f 
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 */
16package com.android.quicksearchbox;
17
18import com.android.quicksearchbox.util.QuietlyCloseable;
19
20import android.database.DataSetObserver;
21
22import java.util.Collection;
23
24/**
25 * A sequence of suggestions, with a current position.
26 */
27public 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    void close();
65
66    /**
67     * Register an observer that is called when changes happen to this data set.
68     *
69     * @param observer gets notified when the data set changes.
70     */
71    void registerDataSetObserver(DataSetObserver observer);
72
73    /**
74     * Unregister an observer that has previously been registered with
75     * {@link #registerDataSetObserver(DataSetObserver)}
76     *
77     * @param observer the observer to unregister.
78     */
79    void unregisterDataSetObserver(DataSetObserver observer);
80
81    /**
82     * Return the extra columns present in this cursor, or null if none exist.
83     */
84    Collection<String> getExtraColumns();
85}
86