java/src/main/com/google/appengine/api/datastore/EnvProxy.java

   1 package com.google.appengine.api.datastore;
   2
   3 import com.google.common.collect.ImmutableMap;
   4
   5 import java.util.Map;
   6
   7 /**
   8  * Proxy around System.getenv() to enable testing and prevent errors in
   9  * situations where the security manager does not allow access to environment
  10  * variables.
  11  */
  12 class EnvProxy {
  13
  14   private static ImmutableMap<String, String> envOverride;
  15
  16   /**
  17    * Updates to {@code envOverride} made after calling this method will not be
  18    * reflected in calls to {@link #getenv(String)}.
  19    */
  20   static synchronized void setEnvOverrideForTest(Map<String, String> envOverride) {
  21     EnvProxy.envOverride = ImmutableMap.copyOf(envOverride);
  22   }
  23
  24   static synchronized void clearEnvOverrideForTest() {
  25     envOverride = null;
  26   }
  27
  28   static String getenv(String name) {
  29     synchronized (EnvProxy.class) {
  30       if (envOverride != null) {
  31         return envOverride.get(name);
  32       }
  33     }
  34     try {
  35       return System.getenv(name);
  36     } catch (SecurityException e) {
  37       return null;
  38     }
  39   }
  40 }