alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

Android example source code file (UriMatcher.java)

This example Android source code file (UriMatcher.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" TM.

Java - Android tags/keywords

android, arraylist, exact, illegalargumentexception, internet, net, network, no_match, number, path_split_pattern, regex, string, text, urimatcher, util

The UriMatcher.java Android example source code

/*
 * 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 UriMatcher objects.
Typically, it looks something like this:
<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();

    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 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:
<pre>
    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;
        }
    }
</pre>
instead of
<pre>
    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;
    }
</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;
}

Other Android examples (source code examples)

Here is a short list of links related to this Android UriMatcher.java source code file:

... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.