utils/src/main/java/org/apache/ode/utils/SystemUtils.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.ode.utils;

import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.Map;

/**
 * Extensions for java.lang.System
 */

public class SystemUtils {
    private static final Pattern PROPERTY_PATTERN = Pattern.compile("\\$\\{([^\\}]+)\\}");

    /**
     * @see System#getProperties()
     */
    public static String javaVersion() {
        return System.getProperty("java.version");
    }

    /**
     * @see System#getProperties()
     */
    public static String javaVendor() {
        return System.getProperty("java.vendor");
    }

    /**
     * @see System#getProperties()
     */
    public static String javaHome() {
        return System.getProperty("java.home");
    }

    /**
     * @see System#getProperties()
     */
    public static String javaClassVersion() {
        return System.getProperty("java.class.version");
    }

    /**
     * @see System#getProperties()
     */
    public static String javaClassPath() {
        return System.getProperty("java.class.path");
    }

    /**
     * @see System#getProperties()
     */
    public static String javaTemporaryDirectory() {
        return System.getProperty("java.io.tmpdir");
    }

    /**
     * @see System#getProperties()
     */
    public static String javaLibraryPath() {
        return System.getProperty("java.library.path");
    }

    /**
     * @see System#getProperties()
     */
    public static String operatingSystemArchitecture() {
        return System.getProperty("os.arch");
    }

    /**
     * @see System#getProperties()
     */
    public static String operatingSystemName() {
        return System.getProperty("os.name");
    }

    /**
     * @see System#getProperties()
     */
    public static String operatingSystemVersion() {
        return System.getProperty("os.version");
    }

    /**
     * @see System#getProperties()
     */
    public static String fileSeparator() {
        return System.getProperty("file.separator");
    }

    /**
     * @see System#getProperties()
     */
    public static String pathSeparator() {
        return System.getProperty("path.separator");
    }

    /**
     * @see System#getProperties()
     */
    public static String lineSeparator() {
        return System.getProperty("line.separator");
    }

    /**
     * @see System#getProperties()
     */
    public static String userName() {
        return System.getProperty("user.name");
    }

    /**
     * @see System#getProperties()
     */
    public static String userHome() {
        return System.getProperty("user.home");
    }

    /**
     * @see System#getProperties()
     */
    public static String userDirectory() {
        return System.getProperty("user.dir");
    }

    /**
     * Replace system property values in the given String using the ${system.property} convention.
     *
     * e.g., "The java version is ${java.version}" ==> "The java version is 1.5.0_11"
     */
    public static String replaceSystemProperties(String str) {
        return replaceProperties(str, PROPERTY_PATTERN, System.getProperties());
    }

    /**
     * Match the received string against the given pattern, and replace each match by the value associated to the first group of the match (group(1)).
     * <br/>If there's no value in the map, no substitution is made.
     * <p>
     * There's one constraint on the regex pattern, it should capture at least one group (i.e. match.groupe(1) should not be null). The value of this group is used to retrieved the replacement value from the map.
     * For instance: pattern = "\\$\\{([^\\}]+)\\}"
     * @param str
     * @param pattern
     * @param values
     * @return
     */
    public static String replaceProperties(String str, Pattern pattern, Map values){
        int start = 0;
        while (true) {
            Matcher match = pattern.matcher(str);
            if (!match.find(start))
                break;
            String property = match.group(1);
            if(property==null) throw new IllegalArgumentException("Regex pattern must capture at least 1 group! "+pattern.toString());
            String value = (String) values.get(property);
            if (value != null) {
                str = match.replaceFirst(Matcher.quoteReplacement(value));
            } else {
                // if the property doesn't exist, no substitution and skip to next
                start = match.end();
            }
        }
        return str;
    }

}