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.Consumers;
21import com.android.quicksearchbox.util.NamedTask;
22import com.android.quicksearchbox.util.NamedTaskExecutor;
23
24import android.os.Handler;
25import android.util.Log;
26
27/**
28 * A task that gets suggestions from a corpus.
29 */
30public class QueryTask<C extends SuggestionCursor> implements NamedTask {
31    private static final String TAG = "QSB.QueryTask";
32    private static final boolean DBG = false;
33
34    private final String mQuery;
35    private final int mQueryLimit;
36    private final SuggestionCursorProvider<C> mProvider;
37    private final Handler mHandler;
38    private final Consumer<C> mConsumer;
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     */
50    public QueryTask(String query, int queryLimit, SuggestionCursorProvider<C> provider,
51            Handler handler, Consumer<C> consumer) {
52        mQuery = query;
53        mQueryLimit = queryLimit;
54        mProvider = provider;
55        mHandler = handler;
56        mConsumer = consumer;
57    }
58
59    @Override
60    public String getName() {
61        return mProvider.getName();
62    }
63
64    @Override
65    public void run() {
66        final C cursor = mProvider.getSuggestions(mQuery, mQueryLimit);
67        if (DBG) Log.d(TAG, "Suggestions from " + mProvider + " = " + cursor);
68        Consumers.consumeCloseableAsync(mHandler, mConsumer, cursor);
69    }
70
71    @Override
72    public String toString() {
73        return mProvider + "[" + mQuery + "]";
74    }
75
76    public static <C extends SuggestionCursor> void startQuery(String query,
77            int maxResults,
78            SuggestionCursorProvider<C> provider,
79            NamedTaskExecutor executor, Handler handler,
80            Consumer<C> consumer) {
81
82        QueryTask<C> task = new QueryTask<C>(query, maxResults, provider, handler,
83                consumer);
84        executor.execute(task);
85    }
86}
87