Util.java

/*
 * @(#)$Id: Util.java,v 1.4 2002/04/28 22:58:45 kk122374 Exp $
 *
 * Copyright 2001 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */
package com.sun.msv.util;

import org.xml.sax.InputSource;
import java.io.File;
import java.net.URL;
import java.net.MalformedURLException;

/**
 * Collection of utility methods.
 * 
 * @author <a href="mailto:kohsuke.kawaguchi@eng.sun.com">Kohsuke KAWAGUCHI</a>
 */
public class Util
{
	/**
	 * Gets an InputSource from a string, which contains either
	 * a file name or an URL.
	 */
	public static InputSource getInputSource( String fileOrURL ) {
		try {
            // try it as an URL
            new URL(fileOrURL);
            return new InputSource(fileOrURL);
        } catch( MalformedURLException e ) {
			// try it as a file
			String path = new File(fileOrURL).getAbsolutePath();
			if (File.separatorChar != '/')
				path = path.replace(File.separatorChar, '/');
			if (!path.startsWith("/"))
				path = "/" + path;
//			if (!path.endsWith("/") && isDirectory())
//				path = path + "/";
            return new InputSource("file://"+path);
		}
	}
	
	/**
	 * Checks if a given string is an absolute URI if it is an URI.
	 * 
	 * <p>
	 * This method does not check whether it is an URI.
	 * 
	 * <p>
	 * This implementation is based on
	 * <a href="http://lists.oasis-open.org/archives/relax-ng/200107/msg00211.html">
	 * this post.</a>
	 */
	public static boolean isAbsoluteURI( String uri ) {
		
		int len = uri.length();
		if(len==0)	return true;	// an empty string is OK.
		if(len<2)	return false;
		
		char ch = uri.charAt(0);
		if(('a'<=ch && ch<='z') || ('A'<=ch && ch<='Z')) {
			
			for( int i=1; i<len; i++ ) {
				ch = uri.charAt(i);
				
				if(ch==':')		return true;
				if(('a'<=ch && ch<='z') || ('A'<=ch && ch<='Z'))	continue;
				if(ch=='-' || ch=='+' || ch=='.')	continue;
				
				return false;	// invalid character
			}
		}
		
		return false;
	}
}