MetadataParser.java revision 0cc0544a2995c7eb54a830ae54db60af89d4073d 
1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
5 * use this file except in compliance with the License. You may obtain a copy of
6 * the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations under
14 * the License.
15 */
16
17package com.android.inputmethod.dictionarypack;
18
19import android.text.TextUtils;
20import android.util.JsonReader;
21
22import java.io.IOException;
23import java.io.InputStreamReader;
24import java.util.ArrayList;
25import java.util.Collections;
26import java.util.List;
27import java.util.TreeMap;
28
29/**
30 * Helper class containing functions to parse the dictionary metadata.
31 */
32public class MetadataParser {
33
34    // Name of the fields in the JSON-formatted file.
35    private static final String ID_FIELD_NAME = MetadataDbHelper.WORDLISTID_COLUMN;
36    private static final String LOCALE_FIELD_NAME = "locale";
37    private static final String DESCRIPTION_FIELD_NAME = MetadataDbHelper.DESCRIPTION_COLUMN;
38    private static final String UPDATE_FIELD_NAME = "update";
39    private static final String FILESIZE_FIELD_NAME = MetadataDbHelper.FILESIZE_COLUMN;
40    private static final String CHECKSUM_FIELD_NAME = MetadataDbHelper.CHECKSUM_COLUMN;
41    private static final String REMOTE_FILENAME_FIELD_NAME =
42            MetadataDbHelper.REMOTE_FILENAME_COLUMN;
43    private static final String VERSION_FIELD_NAME = MetadataDbHelper.VERSION_COLUMN;
44    private static final String FORMATVERSION_FIELD_NAME = MetadataDbHelper.FORMATVERSION_COLUMN;
45
46    /**
47     * Parse one JSON-formatted word list metadata.
48     * @param reader the reader containing the data.
49     * @return a WordListMetadata object from the parsed data.
50     * @throws IOException if the underlying reader throws IOException during reading.
51     */
52    private static WordListMetadata parseOneWordList(final JsonReader reader)
53            throws IOException, BadFormatException {
54        final TreeMap<String, String> arguments = new TreeMap<String, String>();
55        reader.beginObject();
56        while (reader.hasNext()) {
57            final String name = reader.nextName();
58            if (!TextUtils.isEmpty(name)) {
59                arguments.put(name, reader.nextString());
60            }
61        }
62        reader.endObject();
63        if (TextUtils.isEmpty(arguments.get(ID_FIELD_NAME))
64                || TextUtils.isEmpty(arguments.get(LOCALE_FIELD_NAME))
65                || TextUtils.isEmpty(arguments.get(DESCRIPTION_FIELD_NAME))
66                || TextUtils.isEmpty(arguments.get(UPDATE_FIELD_NAME))
67                || TextUtils.isEmpty(arguments.get(FILESIZE_FIELD_NAME))
68                || TextUtils.isEmpty(arguments.get(CHECKSUM_FIELD_NAME))
69                || TextUtils.isEmpty(arguments.get(REMOTE_FILENAME_FIELD_NAME))
70                || TextUtils.isEmpty(arguments.get(VERSION_FIELD_NAME))
71                || TextUtils.isEmpty(arguments.get(FORMATVERSION_FIELD_NAME))) {
72            throw new BadFormatException(arguments.toString());
73        }
74        // TODO: need to find out whether it's bulk or update
75        // The null argument is the local file name, which is not known at this time and will
76        // be decided later.
77        return new WordListMetadata(
78                arguments.get(ID_FIELD_NAME),
79                MetadataDbHelper.TYPE_BULK,
80                arguments.get(DESCRIPTION_FIELD_NAME),
81                Long.parseLong(arguments.get(UPDATE_FIELD_NAME)),
82                Long.parseLong(arguments.get(FILESIZE_FIELD_NAME)),
83                arguments.get(CHECKSUM_FIELD_NAME),
84                null,
85                arguments.get(REMOTE_FILENAME_FIELD_NAME),
86                Integer.parseInt(arguments.get(VERSION_FIELD_NAME)),
87                Integer.parseInt(arguments.get(FORMATVERSION_FIELD_NAME)),
88                0, arguments.get(LOCALE_FIELD_NAME));
89    }
90
91    /**
92     * Parses metadata in the JSON format.
93     * @param input a stream reader expected to contain JSON formatted metadata.
94     * @return dictionary metadata, as an array of WordListMetadata objects.
95     * @throws IOException if the underlying reader throws IOException during reading.
96     * @throws BadFormatException if the data was not in the expected format.
97     */
98    public static List<WordListMetadata> parseMetadata(final InputStreamReader input)
99            throws IOException, BadFormatException {
100        JsonReader reader = new JsonReader(input);
101        final ArrayList<WordListMetadata> readInfo = new ArrayList<WordListMetadata>();
102        reader.beginArray();
103        while (reader.hasNext()) {
104            final WordListMetadata thisMetadata = parseOneWordList(reader);
105            if (!TextUtils.isEmpty(thisMetadata.mLocale))
106                readInfo.add(thisMetadata);
107        }
108        return Collections.unmodifiableList(readInfo);
109    }
110
111}
112