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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 
17 package android.content;
18 
19 import android.net.Uri;
20 
21 import java.util.ArrayList;
22 import java.util.List;
23 import java.util.regex.Pattern;
24 
25 /**
26 Utility 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.
29 For 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
73 the URL that you have been given.  You can use the result to build a query,
74 return a type, insert or delete a row, or whatever you need, without duplicating
75 all 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>
95 instead 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 */
117 public 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      */
UriMatcher(int code)125     public UriMatcher(int code)
126     {
127         mCode = code;
128         mWhich = -1;
129         mChildren = new ArrayList<UriMatcher>();
130         mText = null;
131     }
132 
UriMatcher()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      */
addURI(String authority, String path, int code)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