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.util;
018
019import java.util.regex.Matcher;
020import java.util.regex.Pattern;
021
022/**
023 * A resolver for file paths that supports resolving with system and environment properties.
024 */
025public final class FilePathResolver {
026
027    // must be non greedy patterns
028    private static final Pattern ENV_PATTERN = Pattern.compile("\\$\\{env:(.*?)\\}", Pattern.DOTALL);
029    private static final Pattern SYS_PATTERN = Pattern.compile("\\$\\{(.*?)\\}", Pattern.DOTALL);
030
031    private FilePathResolver() {
032    }
033
034    /**
035     * Resolves the path.
036     * <p/>
037     * The pattern is:
038     * <ul>
039     *   <li><tt>${env.key}</tt> for environment variables.</li>
040     *   <li><tt>${key}</tt> for JVM system properties.</li>
041     * </ul>
042     * For example: <tt>${env.KARAF_HOME}/data/logs</tt>
043     *
044     * @param path  the path
045     * @return the resolved path
046     * @throws IllegalArgumentException is thrown if system property / environment not found
047     */
048    public static String resolvePath(String path) throws IllegalArgumentException {
049        Matcher matcher = ENV_PATTERN.matcher(path);
050        while (matcher.find()) {
051            String key = matcher.group(1);
052            String value = System.getenv(key);
053            if (ObjectHelper.isEmpty(value)) {
054                throw new IllegalArgumentException("Cannot find system environment with key: " + key);
055            }
056            // must quote the replacement to have it work as literal replacement
057            value = Matcher.quoteReplacement(value);
058            path = matcher.replaceFirst(value);
059            // must match again as location is changed
060            matcher = ENV_PATTERN.matcher(path);
061        }
062
063        matcher = SYS_PATTERN.matcher(path);
064        while (matcher.find()) {
065            String key = matcher.group(1);
066            String value = System.getProperty(key);
067            if (ObjectHelper.isEmpty(value)) {
068                throw new IllegalArgumentException("Cannot find JVM system property with key: " + key);
069            }
070            // must quote the replacement to have it work as literal replacement
071            value = Matcher.quoteReplacement(value);
072            path = matcher.replaceFirst(value);
073            // must match again as location is changed
074            matcher = SYS_PATTERN.matcher(path);
075        }
076
077        return path;
078    }
079
080}