src/com/android/globalsearch/SuggestionSources.java - platform/packages/apps/GlobalSearch - Git at Google

 /*
  * Copyright (C) 2009 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 com.android.globalsearch;

 import android.app.SearchManager;
 import android.content.BroadcastReceiver;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.SharedPreferences;
 import android.database.ContentObserver;
 import android.os.Handler;
 import android.provider.Settings;
 import android.server.search.SearchableInfo;
 import android.util.Log;

 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;

 /**
  * Maintains the list of all suggestion sources.
  */
 public class SuggestionSources implements SourceLookup {

     // set to true to enable the more verbose debug logging for this file
     private static final boolean DBG = false;
     private static final String TAG = "SuggestionSources";

     // Name of the preferences file used to store suggestion source preferences
     public static final String PREFERENCES_NAME = "SuggestionSources";

     // The key for the preference that holds the selected web search source
     public static final String WEB_SEARCH_SOURCE_PREF = "web_search_source";

     // An override value for web search providers to provide more results than others.
     private static final int WEB_RESULTS_OVERRIDE_LIMIT = 20;

     private Context mContext;
     private SearchManager mSearchManager;
     private SharedPreferences mPreferences;
     private HashSet<String> mTrustedPackages;
     private boolean mLoaded;

     // All available suggestion sources.
     private SourceList mSuggestionSources;

     // The web search source to use. This is the source selected in the preferences,
     // or the default source if no source has been selected.
     private SuggestionSource mSelectedWebSearchSource;

     // All enabled suggestion sources. This does not include the web search source.
     private ArrayList<SuggestionSource> mEnabledSuggestionSources;

     // Updates the inclusion of the web search provider.
     private ShowWebSuggestionsSettingChangeObserver mShowWebSuggestionsSettingChangeObserver;

     /**
      *
      * @param context Used for looking up source information etc.
      */
     public SuggestionSources(Context context) {
         mContext = context;
         mSearchManager = (SearchManager) context.getSystemService(Context.SEARCH_SERVICE);
         mPreferences = context.getSharedPreferences(PREFERENCES_NAME, Context.MODE_PRIVATE);
         mLoaded = false;
     }

     /**
      * Gets all suggestion sources. This does not include any web search sources.
      *
      * @return A list of suggestion sources, including sources that are not enabled.
      *         Callers must not modify the returned list.
      */
     public synchronized Collection<SuggestionSource> getSuggestionSources() {
         if (!mLoaded) {
             Log.w(TAG, "getSuggestionSources() called, but sources not loaded.");
             return Collections.<SuggestionSource>emptyList();
         }
         return mSuggestionSources.values();
     }

     /** {@inheritDoc} */
     public synchronized SuggestionSource getSourceByComponentName(ComponentName componentName) {
         SuggestionSource source = mSuggestionSources.get(componentName);

         // If the source was not found, back off to check the web source in case it's that.
         if (source == null) {
             if (mSelectedWebSearchSource != null &&
                     mSelectedWebSearchSource.getComponentName().equals(componentName)) {
                 source = mSelectedWebSearchSource;
             }
         }
         return source;
     }

     /**
      * Gets all enabled suggestion sources.
      *
      * @return All enabled suggestion sources (does not include the web search source).
      *         Callers must not modify the returned list.
      */
     public synchronized List<SuggestionSource> getEnabledSuggestionSources() {
         if (!mLoaded) {
             Log.w(TAG, "getEnabledSuggestionSources() called, but sources not loaded.");
             return Collections.<SuggestionSource>emptyList();
         }
         return mEnabledSuggestionSources;
     }

     /**
      * Checks whether a suggestion source is enabled by default.
      */
     public boolean isSourceDefaultEnabled(SuggestionSource source) {
         return true;  // TODO: get from source?
     }

     /** {@inheritDoc} */
     public synchronized SuggestionSource getSelectedWebSearchSource() {
         if (!mLoaded) {
             Log.w(TAG, "getSelectedWebSearchSource() called, but sources not loaded.");
             return null;
         }
         return mSelectedWebSearchSource;
     }

     /**
      * Gets the preference key of the preference for whether the given source
      * is enabled. The preference is stored in the {@link #PREFERENCES_NAME}
      * preferences file.
      */
     public String getSourceEnabledPreference(SuggestionSource source) {
         return "enable_source_" + source.getComponentName().flattenToString();
     }

     // Broadcast receiver for package change notifications
     private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
             String action = intent.getAction();
             if (SearchManager.INTENT_ACTION_SEARCHABLES_CHANGED.equals(action)
                     || SearchManager.INTENT_ACTION_SEARCH_SETTINGS_CHANGED.equals(action)) {
                 // TODO: Instead of rebuilding the whole list on every change,
                 // just add, remove or update the application that has changed.
                 // Adding and updating seem tricky, since I can't see an easy way to list the
                 // launchable activities in a given package.
                 updateSources();
             }
         }
     };

     /**
      * After calling, clients must call {@link #close()} when done with this object.
      */
     public synchronized void load() {
         if (mLoaded) {
             Log.w(TAG, "Already loaded, ignoring call to load().");
             return;
         }

         loadTrustedPackages();

         // Listen for searchables changes.
         mContext.registerReceiver(mBroadcastReceiver,
                 new IntentFilter(SearchManager.INTENT_ACTION_SEARCHABLES_CHANGED));

         // Listen for search preference changes.
         mContext.registerReceiver(mBroadcastReceiver,
                 new IntentFilter(SearchManager.INTENT_ACTION_SEARCH_SETTINGS_CHANGED));

         mShowWebSuggestionsSettingChangeObserver = new ShowWebSuggestionsSettingChangeObserver();
         mContext.getContentResolver().registerContentObserver(
                 Settings.System.getUriFor(Settings.System.SHOW_WEB_SUGGESTIONS),
                 true,
                 mShowWebSuggestionsSettingChangeObserver);

         // update list of sources
         updateSources();
         mLoaded = true;
     }

     /**
      * Releases all resources used by this object. It is possible to call
      * {@link #load()} again after calling this method.
      */
     public synchronized void close() {
         if (!mLoaded) {
             Log.w(TAG, "Not loaded, ignoring call to close().");
             return;
         }
         mContext.unregisterReceiver(mBroadcastReceiver);
         mContext.getContentResolver().unregisterContentObserver(
                 mShowWebSuggestionsSettingChangeObserver);

         mSuggestionSources = null;
         mSelectedWebSearchSource = null;
         mEnabledSuggestionSources = null;
         mLoaded = false;
     }

     // TODO: should get this form a resource file, to allow vendor overlays
     private void loadTrustedPackages() {
         mTrustedPackages = new HashSet<String>();
         mTrustedPackages.add("com.android.contacts");
         mTrustedPackages.add("com.android.browser");
         mTrustedPackages.add("com.android.providers.applications");
     }

     /**
      * Loads the list of suggestion sources. This method is package private so that
      * it can be called efficiently from inner classes.
      */
     /* package */ synchronized void updateSources() {
         mSuggestionSources = new SourceList();
         addExternalSources();

         mEnabledSuggestionSources = findEnabledSuggestionSources();
         mSelectedWebSearchSource = findWebSearchSource();
     }

     private void addExternalSources() {
         ArrayList<SuggestionSource> trusted = new ArrayList<SuggestionSource>();
         ArrayList<SuggestionSource> untrusted = new ArrayList<SuggestionSource>();
         for (SearchableInfo searchable : mSearchManager.getSearchablesInGlobalSearch()) {
             SuggestionSource source = new SearchableSuggestionSource(mContext, searchable);
             if (isTrustedSource(source)) {
                 trusted.add(source);
             } else {
                 untrusted.add(source);
             }
         }
         for (SuggestionSource s : trusted) {
             addSuggestionSource(s);
         }
         for (SuggestionSource s : untrusted) {
             addSuggestionSource(s);
         }
     }

     private void addSuggestionSource(SuggestionSource source) {
         if (DBG) Log.d(TAG, "Adding source: " + source);
         SuggestionSource old = mSuggestionSources.put(source);
         if (old != null) {
             Log.w(TAG, "Replaced source " + old + " for " + source.getComponentName());
         }
     }

     /**
      * Computes the list of enabled suggestion sources.
      */
     private ArrayList<SuggestionSource> findEnabledSuggestionSources() {
         ArrayList<SuggestionSource> enabledSources = new ArrayList<SuggestionSource>();
         for (SuggestionSource source : mSuggestionSources.values()) {
             if (isSourceEnabled(source)) {
                 if (DBG) Log.d(TAG, "Adding enabled source " + source);
                 enabledSources.add(source);
             }
         }
         return enabledSources;
     }

     private boolean isSourceEnabled(SuggestionSource source) {
         boolean defaultEnabled = isSourceDefaultEnabled(source);
         if (mPreferences == null) {
             Log.w(TAG, "Search preferences " + PREFERENCES_NAME + " not found.");
             return true;
         }
         String sourceEnabledPref = getSourceEnabledPreference(source);
         return mPreferences.getBoolean(sourceEnabledPref, defaultEnabled);
     }

     public boolean isTrustedSource(SuggestionSource source) {
         if (source == null) return false;
         final String packageName = source.getComponentName().getPackageName();
         return mTrustedPackages != null && mTrustedPackages.contains(packageName);
     }

     /**
      * Finds the selected web search source.
      */
     private SuggestionSource findWebSearchSource() {
         SuggestionSource webSearchSource = null;
         if (Settings.System.getInt(mContext.getContentResolver(),
                 Settings.System.SHOW_WEB_SUGGESTIONS,
                 1 /* default on until user actually changes it */) == 1) {
             SearchableInfo webSearchable = mSearchManager.getDefaultSearchableForWebSearch();
             if (webSearchable != null) {
                 if (DBG) Log.d(TAG, "Adding web source " + webSearchable.getSearchActivity());
                 // Construct a SearchableSuggestionSource around the web search source. Allow
                 // the web search source to provide a larger number of results with
                 // WEB_RESULTS_OVERRIDE_LIMIT.
                 webSearchSource = SearchableSuggestionSource.create(
                         mContext, webSearchable.getSearchActivity(), WEB_RESULTS_OVERRIDE_LIMIT);
             }
         }
         return webSearchSource;
     }

     /**
      * This works like a map from ComponentName to SuggestionSource,
      * but supports a zero-allocation method for listing all the sources.
      */
     private static class SourceList {

         private HashMap<ComponentName,SuggestionSource> mSourcesByComponent;
         private ArrayList<SuggestionSource> mSources;

         public SourceList() {
             mSourcesByComponent = new HashMap<ComponentName,SuggestionSource>();
             mSources = new ArrayList<SuggestionSource>();
         }

         public SuggestionSource get(ComponentName componentName) {
             return mSourcesByComponent.get(componentName);
         }

         /**
          * Adds a source. Replaces any previous source with the same component name.
          *
          * @return The previous source that was replaced, if any.
          */
         public SuggestionSource put(SuggestionSource source) {
             if (source == null) {
                 return null;
             }
             SuggestionSource old = mSourcesByComponent.put(source.getComponentName(), source);
             if (old != null) {
                 // linear search is ok here, since addSource() is only called when the
                 // list of sources is updated, which is infrequent. Also, collisions would only
                 // happen if there are two sources with the same component name, which should
                 // only happen as long as we have hard-coded sources.
                 mSources.remove(old);
             }
             mSources.add(source);
             return old;
         }

         /**
          * Gets the suggestion sources.
          */
         public ArrayList<SuggestionSource> values() {
             return mSources;
         }

         /**
          * Checks whether the list is empty.
          */
         public boolean isEmpty() {
             return mSources.isEmpty();
         }
     }

     /**
      * ContentObserver which updates the list of enabled sources to include or exclude
      * the web search provider depending on the state of the
      * {@link Settings.System#SHOW_WEB_SUGGESTIONS} setting.
      */
     private class ShowWebSuggestionsSettingChangeObserver extends ContentObserver {
         public ShowWebSuggestionsSettingChangeObserver() {
             super(new Handler());
         }

         @Override
         public void onChange(boolean selfChange) {
             updateSources();
         }
     }
 }
	/*
	* Copyright (C) 2009 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 com.android.globalsearch;

	import android.app.SearchManager;
	import android.content.BroadcastReceiver;
	import android.content.ComponentName;
	import android.content.Context;
	import android.content.Intent;
	import android.content.IntentFilter;
	import android.content.SharedPreferences;
	import android.database.ContentObserver;
	import android.os.Handler;
	import android.provider.Settings;
	import android.server.search.SearchableInfo;
	import android.util.Log;

	import java.util.ArrayList;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.List;

	/**
	* Maintains the list of all suggestion sources.
	*/
	public class SuggestionSources implements SourceLookup {

	// set to true to enable the more verbose debug logging for this file
	private static final boolean DBG = false;
	private static final String TAG = "SuggestionSources";

	// Name of the preferences file used to store suggestion source preferences
	public static final String PREFERENCES_NAME = "SuggestionSources";

	// The key for the preference that holds the selected web search source
	public static final String WEB_SEARCH_SOURCE_PREF = "web_search_source";

	// An override value for web search providers to provide more results than others.
	private static final int WEB_RESULTS_OVERRIDE_LIMIT = 20;

	private Context mContext;
	private SearchManager mSearchManager;
	private SharedPreferences mPreferences;
	private HashSet<String> mTrustedPackages;
	private boolean mLoaded;

	// All available suggestion sources.
	private SourceList mSuggestionSources;

	// The web search source to use. This is the source selected in the preferences,
	// or the default source if no source has been selected.
	private SuggestionSource mSelectedWebSearchSource;

	// All enabled suggestion sources. This does not include the web search source.
	private ArrayList<SuggestionSource> mEnabledSuggestionSources;

	// Updates the inclusion of the web search provider.
	private ShowWebSuggestionsSettingChangeObserver mShowWebSuggestionsSettingChangeObserver;

	/**
	*
	* @param context Used for looking up source information etc.
	*/
	public SuggestionSources(Context context) {
	mContext = context;
	mSearchManager = (SearchManager) context.getSystemService(Context.SEARCH_SERVICE);
	mPreferences = context.getSharedPreferences(PREFERENCES_NAME, Context.MODE_PRIVATE);
	mLoaded = false;
	}

	/**
	* Gets all suggestion sources. This does not include any web search sources.
	*
	* @return A list of suggestion sources, including sources that are not enabled.
	* Callers must not modify the returned list.
	*/
	public synchronized Collection<SuggestionSource> getSuggestionSources() {
	if (!mLoaded) {
	Log.w(TAG, "getSuggestionSources() called, but sources not loaded.");
	return Collections.<SuggestionSource>emptyList();
	}
	return mSuggestionSources.values();
	}

	/** {@inheritDoc} */
	public synchronized SuggestionSource getSourceByComponentName(ComponentName componentName) {
	SuggestionSource source = mSuggestionSources.get(componentName);

	// If the source was not found, back off to check the web source in case it's that.
	if (source == null) {
	if (mSelectedWebSearchSource != null &&
	mSelectedWebSearchSource.getComponentName().equals(componentName)) {
	source = mSelectedWebSearchSource;
	}
	}
	return source;
	}

	/**
	* Gets all enabled suggestion sources.
	*
	* @return All enabled suggestion sources (does not include the web search source).
	* Callers must not modify the returned list.
	*/
	public synchronized List<SuggestionSource> getEnabledSuggestionSources() {
	if (!mLoaded) {
	Log.w(TAG, "getEnabledSuggestionSources() called, but sources not loaded.");
	return Collections.<SuggestionSource>emptyList();
	}
	return mEnabledSuggestionSources;
	}

	/**
	* Checks whether a suggestion source is enabled by default.
	*/
	public boolean isSourceDefaultEnabled(SuggestionSource source) {
	return true; // TODO: get from source?
	}

	/** {@inheritDoc} */
	public synchronized SuggestionSource getSelectedWebSearchSource() {
	if (!mLoaded) {
	Log.w(TAG, "getSelectedWebSearchSource() called, but sources not loaded.");
	return null;
	}
	return mSelectedWebSearchSource;
	}

	/**
	* Gets the preference key of the preference for whether the given source
	* is enabled. The preference is stored in the {@link #PREFERENCES_NAME}
	* preferences file.
	*/
	public String getSourceEnabledPreference(SuggestionSource source) {
	return "enable_source_" + source.getComponentName().flattenToString();
	}

	// Broadcast receiver for package change notifications
	private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
	@Override
	public void onReceive(Context context, Intent intent) {
	String action = intent.getAction();
	if (SearchManager.INTENT_ACTION_SEARCHABLES_CHANGED.equals(action)
	\|\| SearchManager.INTENT_ACTION_SEARCH_SETTINGS_CHANGED.equals(action)) {
	// TODO: Instead of rebuilding the whole list on every change,
	// just add, remove or update the application that has changed.
	// Adding and updating seem tricky, since I can't see an easy way to list the
	// launchable activities in a given package.
	updateSources();
	}
	}
	};

	/**
	* After calling, clients must call {@link #close()} when done with this object.
	*/
	public synchronized void load() {
	if (mLoaded) {
	Log.w(TAG, "Already loaded, ignoring call to load().");
	return;
	}

	loadTrustedPackages();

	// Listen for searchables changes.
	mContext.registerReceiver(mBroadcastReceiver,
	new IntentFilter(SearchManager.INTENT_ACTION_SEARCHABLES_CHANGED));

	// Listen for search preference changes.
	mContext.registerReceiver(mBroadcastReceiver,
	new IntentFilter(SearchManager.INTENT_ACTION_SEARCH_SETTINGS_CHANGED));

	mShowWebSuggestionsSettingChangeObserver = new ShowWebSuggestionsSettingChangeObserver();
	mContext.getContentResolver().registerContentObserver(
	Settings.System.getUriFor(Settings.System.SHOW_WEB_SUGGESTIONS),
	true,
	mShowWebSuggestionsSettingChangeObserver);

	// update list of sources
	updateSources();
	mLoaded = true;
	}

	/**
	* Releases all resources used by this object. It is possible to call
	* {@link #load()} again after calling this method.
	*/
	public synchronized void close() {
	if (!mLoaded) {
	Log.w(TAG, "Not loaded, ignoring call to close().");
	return;
	}
	mContext.unregisterReceiver(mBroadcastReceiver);
	mContext.getContentResolver().unregisterContentObserver(
	mShowWebSuggestionsSettingChangeObserver);

	mSuggestionSources = null;
	mSelectedWebSearchSource = null;
	mEnabledSuggestionSources = null;
	mLoaded = false;
	}

	// TODO: should get this form a resource file, to allow vendor overlays
	private void loadTrustedPackages() {
	mTrustedPackages = new HashSet<String>();
	mTrustedPackages.add("com.android.contacts");
	mTrustedPackages.add("com.android.browser");
	mTrustedPackages.add("com.android.providers.applications");
	}

	/**
	* Loads the list of suggestion sources. This method is package private so that
	* it can be called efficiently from inner classes.
	*/
	/* package */ synchronized void updateSources() {
	mSuggestionSources = new SourceList();
	addExternalSources();

	mEnabledSuggestionSources = findEnabledSuggestionSources();
	mSelectedWebSearchSource = findWebSearchSource();
	}

	private void addExternalSources() {
	ArrayList<SuggestionSource> trusted = new ArrayList<SuggestionSource>();
	ArrayList<SuggestionSource> untrusted = new ArrayList<SuggestionSource>();
	for (SearchableInfo searchable : mSearchManager.getSearchablesInGlobalSearch()) {
	SuggestionSource source = new SearchableSuggestionSource(mContext, searchable);
	if (isTrustedSource(source)) {
	trusted.add(source);
	} else {
	untrusted.add(source);
	}
	}
	for (SuggestionSource s : trusted) {
	addSuggestionSource(s);
	}
	for (SuggestionSource s : untrusted) {
	addSuggestionSource(s);
	}
	}

	private void addSuggestionSource(SuggestionSource source) {
	if (DBG) Log.d(TAG, "Adding source: " + source);
	SuggestionSource old = mSuggestionSources.put(source);
	if (old != null) {
	Log.w(TAG, "Replaced source " + old + " for " + source.getComponentName());
	}
	}

	/**
	* Computes the list of enabled suggestion sources.
	*/
	private ArrayList<SuggestionSource> findEnabledSuggestionSources() {
	ArrayList<SuggestionSource> enabledSources = new ArrayList<SuggestionSource>();
	for (SuggestionSource source : mSuggestionSources.values()) {
	if (isSourceEnabled(source)) {
	if (DBG) Log.d(TAG, "Adding enabled source " + source);
	enabledSources.add(source);
	}
	}
	return enabledSources;
	}

	private boolean isSourceEnabled(SuggestionSource source) {
	boolean defaultEnabled = isSourceDefaultEnabled(source);
	if (mPreferences == null) {
	Log.w(TAG, "Search preferences " + PREFERENCES_NAME + " not found.");
	return true;
	}
	String sourceEnabledPref = getSourceEnabledPreference(source);
	return mPreferences.getBoolean(sourceEnabledPref, defaultEnabled);
	}

	public boolean isTrustedSource(SuggestionSource source) {
	if (source == null) return false;
	final String packageName = source.getComponentName().getPackageName();
	return mTrustedPackages != null && mTrustedPackages.contains(packageName);
	}

	/**
	* Finds the selected web search source.
	*/
	private SuggestionSource findWebSearchSource() {
	SuggestionSource webSearchSource = null;
	if (Settings.System.getInt(mContext.getContentResolver(),
	Settings.System.SHOW_WEB_SUGGESTIONS,
	1 /* default on until user actually changes it */) == 1) {
	SearchableInfo webSearchable = mSearchManager.getDefaultSearchableForWebSearch();
	if (webSearchable != null) {
	if (DBG) Log.d(TAG, "Adding web source " + webSearchable.getSearchActivity());
	// Construct a SearchableSuggestionSource around the web search source. Allow
	// the web search source to provide a larger number of results with
	// WEB_RESULTS_OVERRIDE_LIMIT.
	webSearchSource = SearchableSuggestionSource.create(
	mContext, webSearchable.getSearchActivity(), WEB_RESULTS_OVERRIDE_LIMIT);
	}
	}
	return webSearchSource;
	}

	/**
	* This works like a map from ComponentName to SuggestionSource,
	* but supports a zero-allocation method for listing all the sources.
	*/
	private static class SourceList {

	private HashMap<ComponentName,SuggestionSource> mSourcesByComponent;
	private ArrayList<SuggestionSource> mSources;

	public SourceList() {
	mSourcesByComponent = new HashMap<ComponentName,SuggestionSource>();
	mSources = new ArrayList<SuggestionSource>();
	}

	public SuggestionSource get(ComponentName componentName) {
	return mSourcesByComponent.get(componentName);
	}

	/**
	* Adds a source. Replaces any previous source with the same component name.
	*
	* @return The previous source that was replaced, if any.
	*/
	public SuggestionSource put(SuggestionSource source) {
	if (source == null) {
	return null;
	}
	SuggestionSource old = mSourcesByComponent.put(source.getComponentName(), source);
	if (old != null) {
	// linear search is ok here, since addSource() is only called when the
	// list of sources is updated, which is infrequent. Also, collisions would only
	// happen if there are two sources with the same component name, which should
	// only happen as long as we have hard-coded sources.
	mSources.remove(old);
	}
	mSources.add(source);
	return old;
	}

	/**
	* Gets the suggestion sources.
	*/
	public ArrayList<SuggestionSource> values() {
	return mSources;
	}

	/**
	* Checks whether the list is empty.
	*/
	public boolean isEmpty() {
	return mSources.isEmpty();
	}
	}

	/**
	* ContentObserver which updates the list of enabled sources to include or exclude
	* the web search provider depending on the state of the
	* {@link Settings.System#SHOW_WEB_SUGGESTIONS} setting.
	*/
	private class ShowWebSuggestionsSettingChangeObserver extends ContentObserver {
	public ShowWebSuggestionsSettingChangeObserver() {
	super(new Handler());
	}

	@Override
	public void onChange(boolean selfChange) {
	updateSources();
	}
	}
	}