این وبسایت یک نسخه آزمایشی از سایت developer android می‌باشد که در حال ترجمه می‌باشد.
برای پیوستن به تیم ترجمه و خواندن مستندات اینجا کلیک کنید.
SpeedTracker / Application / src / com.example.android.wearable.speedtracker /

LocationDataManager.java

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/*
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 * Copyright (C) 2014 Google Inc. All Rights Reserved.
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *      http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package com.example.android.wearable.speedtracker;
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import com.example.android.wearable.speedtracker.common.LocationEntry;
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import com.example.android.wearable.speedtracker.common.Utils;
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import com.example.android.wearable.speedtracker.db.LocationDbHelper;
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import java.util.ArrayList;
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import java.util.Calendar;
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import java.util.HashMap;
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import java.util.List;
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import java.util.Map;
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/**
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 * A class that wraps database access and provides a cache for various GPS data.
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 */
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public class LocationDataManager {
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    private final Map<String, List<LocationEntry>> mPointsMap =
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            new HashMap<String, List<LocationEntry>>();
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    private LocationDbHelper mDbHelper;
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    public LocationDataManager(LocationDbHelper dbHelper) {
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        mDbHelper = dbHelper;
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    }
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    /**
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     * Returns a list of {@link com.example.android.wearable.speedtracker.common.LocationEntry}
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     * objects for the day that the {@link java.util.Calendar} object points at. Internally it uses
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     * a cache to speed up subsequent calls. If there is no cached value, it gets the result from
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     * the database.
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     */
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    public final List<LocationEntry> getPoints(Calendar calendar) {
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        String day = Utils.getHashedDay(calendar);
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        synchronized (mPointsMap) {
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            if (mPointsMap.get(day) == null) {
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                // there is no cache for this day, so lets get it from DB
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                List<LocationEntry> points = mDbHelper.read(calendar);
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                mPointsMap.put(day, points);
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            }
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        }
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        return mPointsMap.get(day);
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    }
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    /**
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     * Clears the data for the day that the {@link java.util.Calendar} object falls on. This method
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     * removes the entries from the database and updates the cache accordingly.
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     */
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    public final int clearPoints(Calendar calendar) {
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        synchronized (mPointsMap) {
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            String day = Utils.getHashedDay(calendar);
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            mPointsMap.remove(day);
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            return mDbHelper.delete(day);
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        }
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    }
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    /**
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     * Adds a {@link com.example.android.wearable.speedtracker.common.LocationEntry} point to the
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     * database and cache if it is a new point.
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     */
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    public final void addPoint(LocationEntry entry) {
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        synchronized (mPointsMap) {
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            List<LocationEntry> points = getPoints(entry.calendar);
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            if (points == null || points.isEmpty()) {
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                mDbHelper.insert(entry);
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                if (points == null) {
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                    points = new ArrayList<LocationEntry>();
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                }
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                points.add(entry);
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                mPointsMap.put(entry.day, points);
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            } else {
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                if (!points.contains(entry)) {