001// ***************************************************************************************************************************
002// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
003// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
004// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
005// * with the License.  You may obtain a copy of the License at                                                              *
006// *                                                                                                                         *
007// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
008// *                                                                                                                         *
009// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
010// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
011// * specific language governing permissions and limitations under the License.                                              *
012// ***************************************************************************************************************************
013package org.apache.juneau.internal;
014
015/**
016 * System utilities.
017 */
018public class SystemUtils {
019
020   /**
021    * Returns the first non-<jk>null</jk> system property.
022    *
023    * @param def
024    *    The default value if none are found.
025    *    Can be <jk>null</jk>.
026    * @param keys
027    *    The system properties to look for.
028    * @return
029    *    The first non-<jk>null</jk> system property, or the default value if non were found.
030    */
031   public static String getFirstString(String def, String...keys) {
032      for (String key : keys) {
033         String v = System.getProperty(key);
034         if (v != null)
035            return v;
036      }
037      return def;
038   }
039
040   /**
041    * Returns the first non-<jk>null</jk> boolean system property.
042    *
043    * @param def
044    *    The default value if none are found.
045    *    Can be <jk>null</jk>.
046    * @param keys
047    *    The system properties to look for.
048    * @return
049    *    The first non-<jk>null</jk> system property, or the default value if non were found.
050    */
051   public static Boolean getFirstBoolean(Boolean def, String...keys) {
052      String s = getFirstString(null, keys);
053      return s == null ? def : Boolean.parseBoolean(s);
054   }
055
056   /**
057    * Returns the first non-<jk>null</jk> integer system property.
058    *
059    * @param def
060    *    The default value if none are found.
061    *    Can be <jk>null</jk>.
062    * @param keys
063    *    The system properties to look for.
064    * @return
065    *    The first non-<jk>null</jk> system property, or the default value if non were found.
066    */
067   public static Integer getFirstInteger(Integer def, String...keys) {
068      String s = getFirstString(null, keys);
069      return s == null ? def : Integer.parseInt(s);
070   }
071
072   /**
073    * Convenience method for setting a system property value.
074    *
075    * @param key The system property key.
076    * @param value The system property value.
077    * @param overwrite Overwrite the previous value if it exists.
078    */
079   public static void setProperty(String key, Object value, boolean overwrite) {
080      if (value != null) {
081         if (System.getProperty(key) == null || overwrite)
082            System.setProperty(key, StringUtils.asString(value));
083      }
084   }
085
086   /**
087    * Convenience method for setting a system property value.
088    *
089    * @param key The system property key.
090    * @param value The system property value.
091    */
092   public static void setProperty(String key, Object value) {
093      setProperty(key, value, true);
094   }
095}