DictionaryProvider.java

/*
 * 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.example.android.searchabledict;

import android.app.SearchManager;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.content.res.Resources;
import android.database.Cursor;
import android.database.MatrixCursor;
import android.net.Uri;
import android.text.TextUtils;

import java.util.List;

/**
 * Provides search suggestions for a list of words and their definitions.
 */
public class DictionaryProvider extends ContentProvider {

    public static String AUTHORITY = "dictionary";

    private static final int SEARCH_SUGGEST = 0;
    private static final int SHORTCUT_REFRESH = 1;
    private static final UriMatcher sURIMatcher = buildUriMatcher();

    /**
     * The columns we'll include in our search suggestions.  There are others that could be used
     * to further customize the suggestions, see the docs in {@link SearchManager} for the details
     * on additional columns that are supported.
     */
    private static final String[] COLUMNS = {
            "_id",  // must include this column
            SearchManager.SUGGEST_COLUMN_TEXT_1,
            SearchManager.SUGGEST_COLUMN_TEXT_2,
            SearchManager.SUGGEST_COLUMN_INTENT_DATA,
            };


    /**
     * Sets up a uri matcher for search suggestion and shortcut refresh queries.
     */
    private static UriMatcher buildUriMatcher() {
        UriMatcher matcher =  new UriMatcher(UriMatcher.NO_MATCH);
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY, SEARCH_SUGGEST);
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_QUERY + "/*", SEARCH_SUGGEST);
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_SHORTCUT, SHORTCUT_REFRESH);
        matcher.addURI(AUTHORITY, SearchManager.SUGGEST_URI_PATH_SHORTCUT + "/*", SHORTCUT_REFRESH);
        return matcher;
    }

    @Override
    public boolean onCreate() {
        Resources resources = getContext().getResources();
        Dictionary.getInstance().ensureLoaded(resources);
        return true;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs,
            String sortOrder) {
        if (!TextUtils.isEmpty(selection)) {
            throw new IllegalArgumentException("selection not allowed for " + uri);
        }
        if (selectionArgs != null && selectionArgs.length != 0) {
            throw new IllegalArgumentException("selectionArgs not allowed for " + uri);
        }
        if (!TextUtils.isEmpty(sortOrder)) {
            throw new IllegalArgumentException("sortOrder not allowed for " + uri);
        }
        switch (sURIMatcher.match(uri)) {
            case SEARCH_SUGGEST:
                String query = null;
                if (uri.getPathSegments().size() > 1) {
                    query = uri.getLastPathSegment().toLowerCase();
                }
                return getSuggestions(query, projection);
            case SHORTCUT_REFRESH:
                String shortcutId = null;
                if (uri.getPathSegments().size() > 1) {
                    shortcutId = uri.getLastPathSegment();
                }
                return refreshShortcut(shortcutId, projection);
            default:
                throw new IllegalArgumentException("Unknown URL " + uri);
        }
    }

    private Cursor getSuggestions(String query, String[] projection) {
        String processedQuery = query == null ? "" : query.toLowerCase();
        List<Dictionary.Word> words = Dictionary.getInstance().getMatches(processedQuery);

        MatrixCursor cursor = new MatrixCursor(COLUMNS);
        long id = 0;
        for (Dictionary.Word word : words) {
            cursor.addRow(columnValuesOfWord(id++, word));
        }

        return cursor;
    }

    private Object[] columnValuesOfWord(long id, Dictionary.Word word) {
        return new Object[] {
                id,                  // _id
                word.word,           // text1
                word.definition,     // text2
                word.word,           // intent_data (included when clicking on item)
        };
    }

    /**
     * Note: this is unused as is, but if we included
     * {@link SearchManager#SUGGEST_COLUMN_SHORTCUT_ID} as a column in our results, we
     * could expect to receive refresh queries on this uri for the id provided, in which case we
     * would return a cursor with a single item representing the refreshed suggestion data.
     */
    private Cursor refreshShortcut(String shortcutId, String[] projection) {
        return null;
    }

    /**
     * All queries for this provider are for the search suggestion and shortcut refresh mime type.
     */
    public String getType(Uri uri) {
        switch (sURIMatcher.match(uri)) {
            case SEARCH_SUGGEST:
                return SearchManager.SUGGEST_MIME_TYPE;
            case SHORTCUT_REFRESH:
                return SearchManager.SHORTCUT_MIME_TYPE;
            default:
                throw new IllegalArgumentException("Unknown URL " + uri);
        }
    }

    public Uri insert(Uri uri, ContentValues values) {
        throw new UnsupportedOperationException();
    }

    public int delete(Uri uri, String selection, String[] selectionArgs) {
        throw new UnsupportedOperationException();
    }

    public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
        throw new UnsupportedOperationException();
    }
}