1/*
2 * Copyright (C) 2006 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of 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,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.content;
18
19import android.net.Uri;
20
21import java.util.ArrayList;
22import java.util.List;
23import java.util.regex.Pattern;
24
25/**
26Utility class to aid in matching URIs in content providers.
27
28<p>To use this class, build up a tree of <code>UriMatcher</code> objects.
29For example:
30<pre>
31    private static final int PEOPLE = 1;
32    private static final int PEOPLE_ID = 2;
33    private static final int PEOPLE_PHONES = 3;
34    private static final int PEOPLE_PHONES_ID = 4;
35    private static final int PEOPLE_CONTACTMETHODS = 7;
36    private static final int PEOPLE_CONTACTMETHODS_ID = 8;
37
38    private static final int DELETED_PEOPLE = 20;
39
40    private static final int PHONES = 9;
41    private static final int PHONES_ID = 10;
42    private static final int PHONES_FILTER = 14;
43
44    private static final int CONTACTMETHODS = 18;
45    private static final int CONTACTMETHODS_ID = 19;
46
47    private static final int CALLS = 11;
48    private static final int CALLS_ID = 12;
49    private static final int CALLS_FILTER = 15;
50
51    private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);
52
53    static
54    {
55        sURIMatcher.addURI("contacts", "people", PEOPLE);
56        sURIMatcher.addURI("contacts", "people/#", PEOPLE_ID);
57        sURIMatcher.addURI("contacts", "people/#/phones", PEOPLE_PHONES);
58        sURIMatcher.addURI("contacts", "people/#/phones/#", PEOPLE_PHONES_ID);
59        sURIMatcher.addURI("contacts", "people/#/contact_methods", PEOPLE_CONTACTMETHODS);
60        sURIMatcher.addURI("contacts", "people/#/contact_methods/#", PEOPLE_CONTACTMETHODS_ID);
61        sURIMatcher.addURI("contacts", "deleted_people", DELETED_PEOPLE);
62        sURIMatcher.addURI("contacts", "phones", PHONES);
63        sURIMatcher.addURI("contacts", "phones/filter/*", PHONES_FILTER);
64        sURIMatcher.addURI("contacts", "phones/#", PHONES_ID);
65        sURIMatcher.addURI("contacts", "contact_methods", CONTACTMETHODS);
66        sURIMatcher.addURI("contacts", "contact_methods/#", CONTACTMETHODS_ID);
67        sURIMatcher.addURI("call_log", "calls", CALLS);
68        sURIMatcher.addURI("call_log", "calls/filter/*", CALLS_FILTER);
69        sURIMatcher.addURI("call_log", "calls/#", CALLS_ID);
70    }
71</pre>
72<p>Then when you need to match against a URI, call {@link #match}, providing
73the URL that you have been given.  You can use the result to build a query,
74return a type, insert or delete a row, or whatever you need, without duplicating
75all of the if-else logic that you would otherwise need.  For example:
76<pre>
77    public String getType(Uri url)
78    {
79        int match = sURIMatcher.match(url);
80        switch (match)
81        {
82            case PEOPLE:
83                return "vnd.android.cursor.dir/person";
84            case PEOPLE_ID:
85                return "vnd.android.cursor.item/person";
86... snip ...
87                return "vnd.android.cursor.dir/snail-mail";
88            case PEOPLE_ADDRESS_ID:
89                return "vnd.android.cursor.item/snail-mail";
90            default:
91                return null;
92        }
93    }
94</pre>
95instead of:
96<pre>
97    public String getType(Uri url)
98    {
99        List<String> pathSegments = url.getPathSegments();
100        if (pathSegments.size() >= 2) {
101            if ("people".equals(pathSegments.get(1))) {
102                if (pathSegments.size() == 2) {
103                    return "vnd.android.cursor.dir/person";
104                } else if (pathSegments.size() == 3) {
105                    return "vnd.android.cursor.item/person";
106... snip ...
107                    return "vnd.android.cursor.dir/snail-mail";
108                } else if (pathSegments.size() == 3) {
109                    return "vnd.android.cursor.item/snail-mail";
110                }
111            }
112        }
113        return null;
114    }
115</pre>
116*/
117public class UriMatcher
118{
119    public static final int NO_MATCH = -1;
120    /**
121     * Creates the root node of the URI tree.
122     *
123     * @param code the code to match for the root URI
124     */
125    public UriMatcher(int code)
126    {
127        mCode = code;
128        mWhich = -1;
129        mChildren = new ArrayList<UriMatcher>();
130        mText = null;
131    }
132
133    private UriMatcher()
134    {
135        mCode = NO_MATCH;
136        mWhich = -1;
137        mChildren = new ArrayList<UriMatcher>();
138        mText = null;
139    }
140
141    /**
142     * Add a URI to match, and the code to return when this URI is
143     * matched. URI nodes may be exact match string, the token "*"
144     * that matches any text, or the token "#" that matches only
145     * numbers.
146     *
147     * @param authority the authority to match
148     * @param path the path to match. * may be used as a wild card for
149     * any text, and # may be used as a wild card for numbers.
150     * @param code the code that is returned when a URI is matched
151     * against the given components. Must be positive.
152     */
153    public void addURI(String authority, String path, int code)
154    {
155        if (code < 0) {
156            throw new IllegalArgumentException("code " + code + " is invalid: it must be positive");
157        }
158        String[] tokens = path != null ? PATH_SPLIT_PATTERN.split(path) : null;
159        int numTokens = tokens != null ? tokens.length : 0;
160        UriMatcher node = this;
161        for (int i = -1; i < numTokens; i++) {
162            String token = i < 0 ? authority : tokens[i];
163            ArrayList<UriMatcher> children = node.mChildren;
164            int numChildren = children.size();
165            UriMatcher child;
166            int j;
167            for (j = 0; j < numChildren; j++) {
168                child = children.get(j);
169                if (token.equals(child.mText)) {
170                    node = child;
171                    break;
172                }
173            }
174            if (j == numChildren) {
175                // Child not found, create it
176                child = new UriMatcher();
177                if (token.equals("#")) {
178                    child.mWhich = NUMBER;
179                } else if (token.equals("*")) {
180                    child.mWhich = TEXT;
181                } else {
182                    child.mWhich = EXACT;
183                }
184                child.mText = token;
185                node.mChildren.add(child);
186                node = child;
187            }
188        }
189        node.mCode = code;
190    }
191
192    static final Pattern PATH_SPLIT_PATTERN = Pattern.compile("/");
193
194    /**
195     * Try to match against the path in a url.
196     *
197     * @param uri       The url whose path we will match against.
198     *
199     * @return  The code for the matched node (added using addURI),
200     * or -1 if there is no matched node.
201     */
202    public int match(Uri uri)
203    {
204        final List<String> pathSegments = uri.getPathSegments();
205        final int li = pathSegments.size();
206
207        UriMatcher node = this;
208
209        if (li == 0 && uri.getAuthority() == null) {
210            return this.mCode;
211        }
212
213        for (int i=-1; i<li; i++) {
214            String u = i < 0 ? uri.getAuthority() : pathSegments.get(i);
215            ArrayList<UriMatcher> list = node.mChildren;
216            if (list == null) {
217                break;
218            }
219            node = null;
220            int lj = list.size();
221            for (int j=0; j<lj; j++) {
222                UriMatcher n = list.get(j);
223          which_switch:
224                switch (n.mWhich) {
225                    case EXACT:
226                        if (n.mText.equals(u)) {
227                            node = n;
228                        }
229                        break;
230                    case NUMBER:
231                        int lk = u.length();
232                        for (int k=0; k<lk; k++) {
233                            char c = u.charAt(k);
234                            if (c < '0' || c > '9') {
235                                break which_switch;
236                            }
237                        }
238                        node = n;
239                        break;
240                    case TEXT:
241                        node = n;
242                        break;
243                }
244                if (node != null) {
245                    break;
246                }
247            }
248            if (node == null) {
249                return NO_MATCH;
250            }
251        }
252
253        return node.mCode;
254    }
255
256    private static final int EXACT = 0;
257    private static final int NUMBER = 1;
258    private static final int TEXT = 2;
259
260    private int mCode;
261    private int mWhich;
262    private String mText;
263    private ArrayList<UriMatcher> mChildren;
264}
265