/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */

package android.location;

import java.util.HashMap;

import android.annotation.SystemService;
import android.content.Context;
import android.os.Handler;
import android.os.Looper;
import android.os.RemoteException;
import android.util.Log;

This class provides access to the system country detector service. This
service allows applications to obtain the country that the user is in.

The country will be detected in order of reliability, like

Mobile network
Location
SIM's country
Phone's locale

 Call the detectCountry() to get the available country immediately. 
 To be notified of the future country change, use the addCountryListener 

@hide
/**
 * This class provides access to the system country detector service. This
 * service allows applications to obtain the country that the user is in.
 * <p>
 * The country will be detected in order of reliability, like
 * <ul>
 * <li>Mobile network</li>
 * <li>Location</li>
 * <li>SIM's country</li>
 * <li>Phone's locale</li>
 * </ul>
 * <p>
 * Call the {@link #detectCountry()} to get the available country immediately.
 * <p>
 * To be notified of the future country change, use the
 * {@link #addCountryListener}
 * <p>
 *
 * @hide
 */
@SystemService(Context.COUNTRY_DETECTOR)
public class CountryDetector {

    
The class to wrap the ICountryListener.Stub and CountryListener objects
together. The CountryListener will be notified through the specific
looper once the country changed and detected.
/**
     * The class to wrap the ICountryListener.Stub and CountryListener objects
     * together. The CountryListener will be notified through the specific
     * looper once the country changed and detected.
     */
    private final static class ListenerTransport extends ICountryListener.Stub {

        private final CountryListener mListener;

        private final Handler mHandler;

        public ListenerTransport(CountryListener listener, Looper looper) {
            mListener = listener;
            if (looper != null) {
                mHandler = new Handler(looper);
            } else {
                mHandler = new Handler();
            }
        }

        public void onCountryDetected(final Country country) {
            mHandler.post(new Runnable() {
                public void run() {
                    mListener.onCountryDetected(country);
                }
            });
        }
    }

    private final static String TAG = "CountryDetector";
    private final ICountryDetector mService;
    private final HashMap<CountryListener, ListenerTransport> mListeners;

    
@hide
- hide this constructor because it has a parameter of type
      ICountryDetector, which is a system private class. The right way to
      create an instance of this class is using the factory
      Context.getSystemService./**
     * @hide - hide this constructor because it has a parameter of type
     *       ICountryDetector, which is a system private class. The right way to
     *       create an instance of this class is using the factory
     *       Context.getSystemService.
     */
    public CountryDetector(ICountryDetector service) {
        mService = service;
        mListeners = new HashMap<CountryListener, ListenerTransport>();
    }

    
Start detecting the country that the user is in.
Returns:
the country if it is available immediately, otherwise null will
        be returned./**
     * Start detecting the country that the user is in.
     *
     * @return the country if it is available immediately, otherwise null will
     *         be returned.
     */
    public Country detectCountry() {
        try {
            return mService.detectCountry();
        } catch (RemoteException e) {
            Log.e(TAG, "detectCountry: RemoteException", e);
            return null;
        }
    }

    
Add a listener to receive the notification when the country is detected
or changed.
Params:
listener – will be called when the country is detected or changed.
looper – a Looper object whose message queue will be used to
       implement the callback mechanism. If looper is null then the
       callbacks will be called on the main thread./**
     * Add a listener to receive the notification when the country is detected
     * or changed.
     *
     * @param listener will be called when the country is detected or changed.
     * @param looper a Looper object whose message queue will be used to
     *        implement the callback mechanism. If looper is null then the
     *        callbacks will be called on the main thread.
     */
    public void addCountryListener(CountryListener listener, Looper looper) {
        synchronized (mListeners) {
            if (!mListeners.containsKey(listener)) {
                ListenerTransport transport = new ListenerTransport(listener, looper);
                try {
                    mService.addCountryListener(transport);
                    mListeners.put(listener, transport);
                } catch (RemoteException e) {
                    Log.e(TAG, "addCountryListener: RemoteException", e);
                }
            }
        }
    }

    
Remove the listener
/**
     * Remove the listener
     */
    public void removeCountryListener(CountryListener listener) {
        synchronized (mListeners) {
            ListenerTransport transport = mListeners.get(listener);
            if (transport != null) {
                try {
                    mListeners.remove(listener);
                    mService.removeCountryListener(transport);
                } catch (RemoteException e) {
                    Log.e(TAG, "removeCountryListener: RemoteException", e);
                }
            }
        }
    }
}