001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.camel.component.properties;
018
019import org.apache.camel.util.ObjectHelper;
020
021/**
022 * A {@link org.apache.camel.component.properties.PropertiesFunction} that lookup the property value from
023 * OS environment variables.
024 */
025public class EnvPropertiesFunction implements PropertiesFunction {
026
027    @Override
028    public String getName() {
029        return "env";
030    }
031
032    @Override
033    public String apply(String remainder) {
034        String key = remainder;
035        String defaultValue = null;
036
037        if (remainder.contains(":")) {
038            key = ObjectHelper.before(remainder, ":");
039            defaultValue = ObjectHelper.after(remainder, ":");
040        }
041
042        String value = System.getenv(key);
043        return value != null ? value : defaultValue;
044    }
045
046}