/* * 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.

To use this class, build up a tree of UriMatcher objects. Typically, it looks something like this:

    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();

    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);
    }

Then when you need to match match against a URI, call {@link #match}, providing the tokenized url you've been given, and the value you want if there isn't a match. 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 you'd otherwise need. Like this:

    public String getType(String[] url)
    {
        int match = sURIMatcher.match(url, NO_MATCH);
        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;
        }
    }
instead of
    public String getType(String[] url)
    {
        if (url.length >= 2) {
            if (url[1].equals("people")) {
                if (url.length == 2) {
                    return "vnd.android.cursor.dir/person";
                } else if (url.length == 3) {
                    return "vnd.android.cursor.item/person";
... snip ...
                    return "vnd.android.cursor.dir/snail-mail";
                } else if (url.length == 3) {
                    return "vnd.android.cursor.item/snail-mail";
                }
            }
        }
        return null;
    }
*/ 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(); mText = null; } private UriMatcher() { mCode = NO_MATCH; mWhich = -1; mChildren = new ArrayList(); 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 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 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 list = node.mChildren; if (list == null) { break; } node = null; int lj = list.size(); for (int j=0; j '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 mChildren; }