/*
* Copyright (C) 2006 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 android.content;
import android.net.Uri;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;
/**
Utility class to aid in matching URIs in content providers.
<p>To use this class, build up a tree of <code>UriMatcher</code> objects.
For example:
<pre>
private static final int PEOPLE = 1;
private static final int PEOPLE_ID = 2;
private static final int PEOPLE_PHONES = 3;
private static final int PEOPLE_PHONES_ID = 4;
private static final int PEOPLE_CONTACTMETHODS = 7;
private static final int PEOPLE_CONTACTMETHODS_ID = 8;
private static final int DELETED_PEOPLE = 20;
private static final int PHONES = 9;
private static final int PHONES_ID = 10;
private static final int PHONES_FILTER = 14;
private static final int CONTACTMETHODS = 18;
private static final int CONTACTMETHODS_ID = 19;
private static final int CALLS = 11;
private static final int CALLS_ID = 12;
private static final int CALLS_FILTER = 15;
private static final UriMatcher sURIMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static
{
sURIMatcher.addURI("contacts", "people", PEOPLE);
sURIMatcher.addURI("contacts", "people/#", PEOPLE_ID);
sURIMatcher.addURI("contacts", "people/#/phones", PEOPLE_PHONES);
sURIMatcher.addURI("contacts", "people/#/phones/#", PEOPLE_PHONES_ID);
sURIMatcher.addURI("contacts", "people/#/contact_methods", PEOPLE_CONTACTMETHODS);
sURIMatcher.addURI("contacts", "people/#/contact_methods/#", PEOPLE_CONTACTMETHODS_ID);
sURIMatcher.addURI("contacts", "deleted_people", DELETED_PEOPLE);
sURIMatcher.addURI("contacts", "phones", PHONES);
sURIMatcher.addURI("contacts", "phones/filter/*", PHONES_FILTER);
sURIMatcher.addURI("contacts", "phones/#", PHONES_ID);
sURIMatcher.addURI("contacts", "contact_methods", CONTACTMETHODS);
sURIMatcher.addURI("contacts", "contact_methods/#", CONTACTMETHODS_ID);
sURIMatcher.addURI("call_log", "calls", CALLS);
sURIMatcher.addURI("call_log", "calls/filter/*", CALLS_FILTER);
sURIMatcher.addURI("call_log", "calls/#", CALLS_ID);
}
</pre>
<p>Then when you need to match against a URI, call {@link #match}, providing
the URL that you have been given. You can use the result to build a query,
return a type, insert or delete a row, or whatever you need, without duplicating
all of the if-else logic that you would otherwise need. For example:
<pre>
public String getType(Uri url)
{
int match = sURIMatcher.match(url);
switch (match)
{
case PEOPLE:
return "vnd.android.cursor.dir/person";
case PEOPLE_ID:
return "vnd.android.cursor.item/person";
... snip ...
return "vnd.android.cursor.dir/snail-mail";
case PEOPLE_ADDRESS_ID:
return "vnd.android.cursor.item/snail-mail";
default:
return null;
}
}
</pre>
instead of:
<pre>
public String getType(Uri url)
{
List<String> pathSegments = url.getPathSegments();
if (pathSegments.size() >= 2) {
if ("people".equals(pathSegments.get(1))) {
if (pathSegments.size() == 2) {
return "vnd.android.cursor.dir/person";
} else if (pathSegments.size() == 3) {
return "vnd.android.cursor.item/person";
... snip ...
return "vnd.android.cursor.dir/snail-mail";
} else if (pathSegments.size() == 3) {
return "vnd.android.cursor.item/snail-mail";
}
}
}
return null;
}
</pre>
*/
public class UriMatcher
{
public static final int NO_MATCH = -1;
/**
* Creates the root node of the URI tree.
*
* @param code the code to match for the root URI
*/
public UriMatcher(int code)
{
mCode = code;
mWhich = -1;
mChildren = new ArrayList<UriMatcher>();
mText = null;
}
private UriMatcher()
{
mCode = NO_MATCH;
mWhich = -1;
mChildren = new ArrayList<UriMatcher>();
mText = null;
}
/**
* Add a URI to match, and the code to return when this URI is
* matched. URI nodes may be exact match string, the token "*"
* that matches any text, or the token "#" that matches only
* numbers.
*
* @param authority the authority to match
* @param path the path to match. * may be used as a wild card for
* any text, and # may be used as a wild card for numbers.
* @param code the code that is returned when a URI is matched
* against the given components. Must be positive.
*/
public void addURI(String authority, String path, int code)
{
if (code < 0) {
throw new IllegalArgumentException("code " + code + " is invalid: it must be positive");
}
String[] tokens = path != null ? PATH_SPLIT_PATTERN.split(path) : null;
int numTokens = tokens != null ? tokens.length : 0;
UriMatcher node = this;
for (int i = -1; i < numTokens; i++) {
String token = i < 0 ? authority : tokens[i];
ArrayList<UriMatcher> children = node.mChildren;
int numChildren = children.size();
UriMatcher child;
int j;
for (j = 0; j < numChildren; j++) {
child = children.get(j);
if (token.equals(child.mText)) {
node = child;
break;
}
}
if (j == numChildren) {
// Child not found, create it
child = new UriMatcher();
if (token.equals("#")) {
child.mWhich = NUMBER;
} else if (token.equals("*")) {
child.mWhich = TEXT;
} else {
child.mWhich = EXACT;
}
child.mText = token;
node.mChildren.add(child);
node = child;
}
}
node.mCode = code;
}
static final Pattern PATH_SPLIT_PATTERN = Pattern.compile("/");
/**
* Try to match against the path in a url.
*
* @param uri The url whose path we will match against.
*
* @return The code for the matched node (added using addURI),
* or -1 if there is no matched node.
*/
public int match(Uri uri)
{
final List<String> pathSegments = uri.getPathSegments();
final int li = pathSegments.size();
UriMatcher node = this;
if (li == 0 && uri.getAuthority() == null) {
return this.mCode;
}
for (int i=-1; i<li; i++) {
String u = i < 0 ? uri.getAuthority() : pathSegments.get(i);
ArrayList<UriMatcher> list = node.mChildren;
if (list == null) {
break;
}
node = null;
int lj = list.size();
for (int j=0; j<lj; j++) {
UriMatcher n = list.get(j);
which_switch:
switch (n.mWhich) {
case EXACT:
if (n.mText.equals(u)) {
node = n;
}
break;
case NUMBER:
int lk = u.length();
for (int k=0; k<lk; k++) {
char c = u.charAt(k);
if (c < '0' || c > '9') {
break which_switch;
}
}
node = n;
break;
case TEXT:
node = n;
break;
}
if (node != null) {
break;
}
}
if (node == null) {
return NO_MATCH;
}
}
return node.mCode;
}
private static final int EXACT = 0;
private static final int NUMBER = 1;
private static final int TEXT = 2;
private int mCode;
private int mWhich;
private String mText;
private ArrayList<UriMatcher> mChildren;
}