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   private EnvProxy() {}
  17
  18   /**
  19    * Updates to {@code envOverride} made after calling this method will not be
  20    * reflected in calls to {@link #getenv(String)}.
  21    */
  22   static synchronized void setEnvOverrideForTest(Map<String, String> envOverride) {
  23     EnvProxy.envOverride = ImmutableMap.copyOf(envOverride);
  24   }
  25
  26   static synchronized void clearEnvOverrideForTest() {
  27     envOverride = null;
  28   }
  29
  30   static String getenv(String name) {
  31     synchronized (EnvProxy.class) {
  32       if (envOverride != null) {
  33         return envOverride.get(name);
  34       }
  35     }
  36     try {
  37       return System.getenv(name);
  38     } catch (SecurityException e) {
  39       return null;
  40     }
  41   }
  42 }