/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2008 University of Maryland
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.util;

import java.io.File;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.annotation.Nonnull;

/**
 * Some utility methods for working with the Java class path.
 * 
 * @author David Hovemeyer
 */
public class ClassPathUtil {
	/**
	 * Try to find a codebase with the given name in the given
	 * class path string.
	 * 
	 * @param codeBaseName name of a codebase (e.g., "findbugs.jar")
	 * @param classPath    a classpath
	 * @return full path of named codebase, or null if the codebase couldn't be found
	 */
	public static String findCodeBaseInClassPath(@Nonnull String codeBaseName, String classPath) {
		if (classPath == null) {
			return null;
		}
		
		StringTokenizer tok = new StringTokenizer(classPath, File.pathSeparator);
		while (tok.hasMoreTokens()) {
			String t = tok.nextToken();
			File f = new File(t);
			if (f.getName().equals(codeBaseName)) {
				return t;
			}
		}
	
		return null;
	}
	
	/**
	 * Try to find a codebase matching the given pattern in the given
	 * class path string.
	 * 
	 * @param codeBaseNamePattern pattern describing a codebase
	 *        (e.g., compiled from the regex "findbugs\\.jar$")
	 * @param classPath    a classpath
	 * @return full path of named codebase, or null if the codebase couldn't be found
	 */
	public static String findCodeBaseInClassPath(Pattern codeBaseNamePattern, String classPath) {
		if (classPath == null) {
			return null;
		}
		
		StringTokenizer tok = new StringTokenizer(classPath, File.pathSeparator);
		while (tok.hasMoreTokens()) {
			String t = tok.nextToken();
			File f = new File(t);
			Matcher m = codeBaseNamePattern.matcher(f.getName());
			if (m.matches()) {
				return t;
			}
		}
	
		return null;
	}
	
	public static String[] getJavaClassPath() {
		return System.getProperty("java.class.path").split(":");
	}
}