/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 org.apache.harmony.jndi.internal;
/**
* Identifies the simplest URL syntax:
* <code>{scheme}:{scheme specific part}</code>.
*/
public class UrlParser {
/*
* Prevent instantiate.
*/
private UrlParser() {
super();
}
/**
* Returns an URL's scheme part, in lower case. If the url is not a valid
* URL, null is returned.
*
* @param url
* a url string
* @return the URL's scheme part, in lower case. If the url is not a valid
* URL, null is returned.
*/
public static String getScheme(String url) {
if (null == url) {
return null;
}
int colPos = url.indexOf(':');
if (colPos < 0) {
return null;
}
String scheme = url.substring(0, colPos);
char c;
boolean inCharSet;
for (int i = 0; i < scheme.length(); i++) {
c = scheme.charAt(i);
inCharSet = (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z')
|| (c >= '0' && c <= '9') || c == '+' || c == '.'
|| c == '-' || c == '_';
if (!inCharSet) {
return null;
}
}
return scheme;
}
}