QueryTask.java revision 848fa7a19abedc372452073abaf52780c7b6d78d 
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
17package com.android.quicksearchbox;
18
19import com.android.quicksearchbox.util.Consumer;
20import com.android.quicksearchbox.util.NamedTask;
21import com.android.quicksearchbox.util.NamedTaskExecutor;
22
23import android.os.Handler;
24import android.util.Log;
25
26/**
27 * A task that gets suggestions from a corpus.
28 */
29public class QueryTask<C extends SuggestionCursor> implements NamedTask {
30    private static final String TAG = "QSB.QueryTask";
31    private static final boolean DBG = false;
32
33    private final String mQuery;
34    private final int mQueryLimit;
35    private final SuggestionCursorProvider<C> mProvider;
36    private final Handler mHandler;
37    private final Consumer<C> mConsumer;
38    private final boolean mTheOnlyOne;
39
40    /**
41     * Creates a new query task.
42     *
43     * @param query Query to run.
44     * @param queryLimit The number of suggestions to ask each provider for.
45     * @param provider The provider to ask for suggestions.
46     * @param handler Handler that {@link Consumer#consume} will
47     *        get called on. If null, the method is called on the query thread.
48     * @param consumer Consumer to notify when the suggestions have been returned.
49     * @param onlyTask Indicates if this is the only task within a batch.
50     */
51    public QueryTask(String query, int queryLimit, SuggestionCursorProvider<C> provider,
52            Handler handler, Consumer<C> consumer, boolean onlyTask) {
53        mQuery = query;
54        mQueryLimit = queryLimit;
55        mProvider = provider;
56        mHandler = handler;
57        mConsumer = consumer;
58        mTheOnlyOne = onlyTask;
59    }
60
61    public String getName() {
62        return mProvider.getName();
63    }
64
65    public void run() {
66        final C cursor = mProvider.getSuggestions(mQuery, mQueryLimit, mTheOnlyOne);
67        if (DBG) Log.d(TAG, "Suggestions from " + mProvider + " = " + cursor);
68        if (mHandler == null) {
69            mConsumer.consume(cursor);
70        } else {
71            mHandler.post(new Runnable() {
72                public void run() {
73                    boolean accepted = mConsumer.consume(cursor);
74                    if (!accepted) {
75                        cursor.close();
76                    }
77                }
78            });
79        }
80    }
81
82    @Override
83    public String toString() {
84        return mProvider + "[" + mQuery + "]";
85    }
86
87    public static <C extends SuggestionCursor> void startQueries(String query,
88            int maxResultsPerProvider,
89            Iterable<? extends SuggestionCursorProvider<C>> providers,
90            NamedTaskExecutor executor, Handler handler,
91            Consumer<C> consumer, boolean onlyOneProvider) {
92
93        for (SuggestionCursorProvider<C> provider : providers) {
94            QueryTask<C> task = new QueryTask<C>(query, maxResultsPerProvider, provider, handler,
95                    consumer, onlyOneProvider);
96            executor.execute(task);
97        }
98    }
99
100}
101