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 android.os.Handler;
20import android.util.Log;
21
22import com.android.quicksearchbox.util.BatchingNamedTaskExecutor;
23import com.android.quicksearchbox.util.Consumer;
24import com.android.quicksearchbox.util.NamedTaskExecutor;
25import com.android.quicksearchbox.util.NoOpConsumer;
26
27/**
28 * Suggestions provider implementation.
29 *
30 * The provider will only handle a single query at a time. If a new query comes
31 * in, the old one is cancelled.
32 */
33public class SuggestionsProviderImpl implements SuggestionsProvider {
34
35    private static final boolean DBG = false;
36    private static final String TAG = "QSB.SuggestionsProviderImpl";
37
38    private final Config mConfig;
39
40    private final NamedTaskExecutor mQueryExecutor;
41
42    private final Handler mPublishThread;
43
44    private final Logger mLogger;
45
46    public SuggestionsProviderImpl(Config config,
47            NamedTaskExecutor queryExecutor,
48            Handler publishThread,
49            Logger logger) {
50        mConfig = config;
51        mQueryExecutor = queryExecutor;
52        mPublishThread = publishThread;
53        mLogger = logger;
54    }
55
56    @Override
57    public void close() {
58    }
59
60    @Override
61    public Suggestions getSuggestions(String query, Source sourceToQuery) {
62        if (DBG) Log.d(TAG, "getSuggestions(" + query + ")");
63        final Suggestions suggestions = new Suggestions(query, sourceToQuery);
64        Log.i(TAG, "chars:" + query.length() + ",source:" + sourceToQuery);
65
66        Consumer<SourceResult> receiver;
67        if (shouldDisplayResults(query)) {
68            receiver = new SuggestionCursorReceiver(suggestions);
69        } else {
70            receiver = new NoOpConsumer<SourceResult>();
71            suggestions.done();
72        }
73
74        int maxResults = mConfig.getMaxResultsPerSource();
75        QueryTask.startQuery(query, maxResults, sourceToQuery, mQueryExecutor,
76                mPublishThread, receiver);
77
78        return suggestions;
79    }
80
81    private boolean shouldDisplayResults(String query) {
82        if (query.length() == 0 && !mConfig.showSuggestionsForZeroQuery()) {
83            // Note that even though we don't display such results, it's
84            // useful to run the query itself because it warms up the network
85            // connection.
86            return false;
87        }
88        return true;
89    }
90
91
92    private class SuggestionCursorReceiver implements Consumer<SourceResult> {
93        private final Suggestions mSuggestions;
94
95        public SuggestionCursorReceiver(Suggestions suggestions) {
96            mSuggestions = suggestions;
97        }
98
99        @Override
100        public boolean consume(SourceResult cursor) {
101            if (DBG) {
102                Log.d(TAG, "SuggestionCursorReceiver.consume(" + cursor + ") corpus=" +
103                        cursor.getSource() + " count = " + cursor.getCount());
104            }
105            // publish immediately
106            if (DBG) Log.d(TAG, "Publishing results");
107            mSuggestions.addResults(cursor);
108            if (cursor != null && mLogger != null) {
109                mLogger.logLatency(cursor);
110            }
111            return true;
112        }
113
114    }
115}
116