gecko/mobile/android/base/home/SearchLoader.java

/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

package org.mozilla.gecko.home;

import org.mozilla.gecko.db.BrowserDB;

import android.content.Context;
import android.database.Cursor;
import android.os.Bundle;
import android.support.v4.app.LoaderManager;
import android.support.v4.app.LoaderManager.LoaderCallbacks;
import android.support.v4.content.Loader;
import android.text.TextUtils;

/**
 * Encapsulates the implementation of the search cursor loader.
 */
class SearchLoader {
    // Key for search terms
    private static final String KEY_SEARCH_TERM = "search_term";

    // Key for performing empty search
    private static final String KEY_PERFORM_EMPTY_SEARCH = "perform_empty_search";

    private SearchLoader() {
    }

    public static Loader<Cursor> createInstance(Context context, Bundle args) {
        if (args != null) {
            final String searchTerm = args.getString(KEY_SEARCH_TERM);
            final boolean performEmptySearch = args.getBoolean(KEY_PERFORM_EMPTY_SEARCH, false);
            return new SearchCursorLoader(context, searchTerm, performEmptySearch);
        } else {
            return new SearchCursorLoader(context, "", false);
        }
    }

    public static void restart(LoaderManager manager, int loaderId,
                               LoaderCallbacks<Cursor> callbacks, String searchTerm) {
        restart(manager, loaderId, callbacks, searchTerm, true);
    }

    public static void restart(LoaderManager manager, int loaderId,
                               LoaderCallbacks<Cursor> callbacks, String searchTerm, boolean performEmptySearch) {
        Bundle bundle = new Bundle();
        bundle.putString(SearchLoader.KEY_SEARCH_TERM, searchTerm);
        bundle.putBoolean(SearchLoader.KEY_PERFORM_EMPTY_SEARCH, performEmptySearch);
        manager.restartLoader(loaderId, bundle, callbacks);
    }

    public static class SearchCursorLoader extends SimpleCursorLoader {
        // Max number of search results
        private static final int SEARCH_LIMIT = 100;

        // The target search term associated with the loader
        private final String mSearchTerm;

        // An empty search on the DB
        private final boolean mPerformEmptySearch;

        public SearchCursorLoader(Context context, String searchTerm, boolean performEmptySearch) {
            super(context);
            mSearchTerm = searchTerm;
            mPerformEmptySearch = performEmptySearch;
        }

        @Override
        public Cursor loadCursor() {
            if (!mPerformEmptySearch && TextUtils.isEmpty(mSearchTerm)) {
                return null;
            }

            return BrowserDB.filter(getContext().getContentResolver(), mSearchTerm, SEARCH_LIMIT);
        }

        public String getSearchTerm() {
            return mSearchTerm;
        }
    }

}