001 /*
002 * $RCSfile: VariablesToolkit.java,v $
003 *
004 * Created on December 19, 2002, 3:29 PM
005 *
006 * This file is part of the STAR Scheduler.
007 * Copyright (c) 2002-2006 STAR Collaboration - Brookhaven National Laboratory
008 *
009 * STAR Scheduler is free software; you can redistribute it and/or modify
010 * it under the terms of the GNU General Public License as published by
011 * the Free Software Foundation; either version 2 of the License, or
012 * (at your option) any later version.
013 *
014 * STAR Scheduler is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
017 * GNU General Public License for more details.
018 *
019 * You should have received a copy of the GNU General Public License
020 * along with STAR Scheduler; if not, write to the Free Software
021 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
022 */
023 package gov.bnl.star.offline.scheduler.util;
024
025 import java.net.URL;
026
027 import java.util.Map;
028 import java.util.logging.Level;
029 import org.apache.log4j.Logger;
030
031
032 /** Utility class for environment variables, mainly variable substitution.
033 * @author Gabriele Carcassi
034 * @version $Revision: 1.8 $ $Date: 2006/11/21 00:41:29 $
035 */
036 public class VariablesToolkit {
037 static private Logger log = Logger.getLogger(VariablesToolkit.class.getName());
038
039 /** Creates a new instance of VariablesToolkit */
040 private VariablesToolkit() {
041 }
042
043 /* Given a URL, substitutes environment variable that might be present in
044 * the path and filename.
045 */
046
047 /** Substitutes the envirnoment varilables present in the path of the URL.
048 * @param url the URL with environment variables
049 * @param variables a map from variable names to values
050 * @return the URL with expanded variables
051 */
052 public static URL substituteVariables(URL url, Map variables) {
053 String temp = url.toString();
054 temp = substituteVariables(temp, variables);
055
056 try {
057 return new URL(temp);
058 } catch (Exception e) {
059 // The substitution created an invalid URL
060 log.error("A URL variable substitution failed: " + url + " - " + temp, e);
061 throw new RuntimeException( "The environment variable substitution in the following URL led to an error: " + url);
062 }
063 }
064
065 /* Given a generic test String, substitutes all the variables that might
066 * be present in the variables list.
067 */
068
069 /** Substitutes the envirnoment varilables present in a String.
070 * @param text the text with environment variables
071 * @param variables a map from variable names to values
072 * @return the text with expanded variables
073 */
074 public static String substituteVariables(String text, Map variables) {
075 StringBuffer temp = new StringBuffer(text);
076 int offset = 0;
077 int current = 0;
078
079 // Continue when there are no more '$' characters
080 while ((current = temp.indexOf("$", offset)) != -1) {
081 int varLength = 1;
082
083 // Determine the length of the text that includes the environment
084 // variable
085 while (((current + varLength) < temp.length()) && Character.isLetterOrDigit(temp.charAt(current + varLength)))
086 varLength++;
087
088 String varName = temp.toString().substring(current + 1,
089 current + varLength);
090 log.debug("Substituting variable " + varName + " in " + text);
091
092 // Find a variable with the proper name. If it is not found,
093 // leave the text as it is and go on.
094 String value = (String) variables.get(varName);
095
096 if (value != null) {
097 temp.replace(current, current + varLength, value);
098 offset = current + value.length();
099 } else {
100 offset++;
101 }
102 }
103
104 return temp.toString();
105 }
106 }