Logback: the reliable, generic, fast and flexible logging framework.
Copyright (C) 1999-2015, QOS.ch. All rights reserved.
This program and the accompanying materials are dual-licensed under
either the terms of the Eclipse Public License v1.0 as published by
the Eclipse Foundation
  or (per the licensee's choosing)
under the terms of the GNU Lesser General Public License version 2.1
as published by the Free Software Foundation.
/**
 * Logback: the reliable, generic, fast and flexible logging framework.
 * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
 *
 * This program and the accompanying materials are dual-licensed under
 * either the terms of the Eclipse Public License v1.0 as published by
 * the Eclipse Foundation
 *
 *   or (per the licensee's choosing)
 *
 * under the terms of the GNU Lesser General Public License version 2.1
 * as published by the Free Software Foundation.
 */
package ch.qos.logback.core.util;

import java.io.FileNotFoundException;
import java.net.MalformedURLException;
import java.net.URL;

A static utility method that converts a string that describes the location of a resource into a URL object. 
Author:
Carl Harris/**
 * A static utility method that converts a string that describes the
 * location of a resource into a {@link URL} object.
 *
 * @author Carl Harris
 */
public class LocationUtil {

    
Regex pattern for a URL scheme (reference RFC 2396 section 3) /** Regex pattern for a URL scheme (reference RFC 2396 section 3) */
    public static final String SCHEME_PATTERN = "^\\p{Alpha}[\\p{Alnum}+.-]*:.*$";

    
Scheme name for a classpath resource /** Scheme name for a classpath resource */
    public static final String CLASSPATH_SCHEME = "classpath:";

    
Converts a string describing the location of a resource into a URL object.
Params:
location – String describing the location
Throws:
MalformedURLException – if location is not a syntatically valid URL
FileNotFoundException – if location specifies a non-existent classpath resource
NullPointerException – if location is null
Returns:
URL object that refers to location/**
     * Converts a string describing the location of a resource into a URL object.
     * @param location String describing the location
     * @return URL object that refers to {@code location}
     * @throws MalformedURLException if {@code location} is not a syntatically
     *    valid URL
     * @throws FileNotFoundException if {@code location} specifies a non-existent
     *    classpath resource
     * @throws NullPointerException if {@code location} is {@code null}
     */
    public static URL urlForResource(String location) throws MalformedURLException, FileNotFoundException {
        if (location == null) {
            throw new NullPointerException("location is required");
        }
        URL url = null;
        if (!location.matches(SCHEME_PATTERN)) {
            url = Loader.getResourceBySelfClassLoader(location);
        } else if (location.startsWith(CLASSPATH_SCHEME)) {
            String path = location.substring(CLASSPATH_SCHEME.length());
            if (path.startsWith("/")) {
                path = path.substring(1);
            }
            if (path.length() == 0) {
                throw new MalformedURLException("path is required");
            }
            url = Loader.getResourceBySelfClassLoader(path);
        } else {
            url = new URL(location);
        }
        if (url == null) {
            throw new FileNotFoundException(location);
        }
        return url;
    }

}