001    package org.apache.maven.properties.internal;
002    
003    /*
004     * Licensed to the Apache Software Foundation (ASF) under one
005     * or more contributor license agreements.  See the NOTICE file
006     * distributed with this work for additional information
007     * regarding copyright ownership.  The ASF licenses this file
008     * to you under the Apache License, Version 2.0 (the
009     * "License"); you may not use this file except in compliance
010     * with the License.  You may obtain a copy of the License at
011     *
012     *   http://www.apache.org/licenses/LICENSE-2.0
013     *
014     * Unless required by applicable law or agreed to in writing,
015     * software distributed under the License is distributed on an
016     * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
017     * KIND, either express or implied.  See the License for the
018     * specific language governing permissions and limitations
019     * under the License.
020     */
021    
022    import java.util.Locale;
023    import java.util.Map;
024    import java.util.Properties;
025    
026    import org.codehaus.plexus.util.Os;
027    
028    /**
029     * Assists the project builder. <strong>Warning:</strong> This is an internal utility class that is only public for
030     * technical reasons, it is not part of the public API. In particular, this class can be changed or deleted without
031     * prior notice.
032     * 
033     * @since 3.0
034     * @author Benjamin Bentmann
035     */
036    public class EnvironmentUtils
037    {
038    
039        private static Properties envVars;
040    
041        /**
042         * Adds the environment variables in the form of properties whose keys are prefixed with {@code env.}, e.g. {@code
043         * env.PATH}. Unlike native environment variables, properties are always case-sensitive. For the sake of
044         * determinism, the environment variable names will be normalized to upper case on platforms with case-insensitive
045         * variable lookup.
046         * 
047         * @param props The properties to add the environment variables to, may be {@code null}.
048         */
049        public static void addEnvVars( Properties props )
050        {
051            if ( props != null )
052            {
053                if ( envVars == null )
054                {
055                    Properties tmp = new Properties();
056                    boolean caseSensitive = !Os.isFamily( Os.FAMILY_WINDOWS );
057                    for ( Map.Entry<String, String> entry : System.getenv().entrySet() )
058                    {
059                        String key =
060                            "env." + ( caseSensitive ? entry.getKey() : entry.getKey().toUpperCase( Locale.ENGLISH ) );
061                        tmp.setProperty( key, entry.getValue() );
062                    }
063                    envVars = tmp;
064                }
065    
066                props.putAll( envVars );
067            }
068        }
069    
070    }