Extract sharedDirectory config key into a constant

Change-Id: Ic3e8901ee1c09f4099ae2cc94b554814fd16b004
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java
index b756678..5893715 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Configuration.java
@@ -28,6 +28,7 @@
 public class Configuration {
   private static final Logger log = LoggerFactory.getLogger(Configuration.class);
 
+  static final String SHARED_DIRECTORY = "sharedDirectory";
   static final String URL_KEY = "url";
   static final String USER_KEY = "user";
   static final String PASSWORD_KEY = "password";
diff --git a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Module.java b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Module.java
index f547260..a8d017c 100644
--- a/src/main/java/com/ericsson/gerrit/plugins/highavailability/Module.java
+++ b/src/main/java/com/ericsson/gerrit/plugins/highavailability/Module.java
@@ -14,6 +14,8 @@
 
 package com.ericsson.gerrit.plugins.highavailability;
 
+import static com.ericsson.gerrit.plugins.highavailability.Configuration.SHARED_DIRECTORY;
+
 import com.ericsson.gerrit.plugins.highavailability.cache.CacheModule;
 import com.ericsson.gerrit.plugins.highavailability.event.EventModule;
 import com.ericsson.gerrit.plugins.highavailability.forwarder.rest.RestForwarderModule;
@@ -50,9 +52,9 @@
   Path getSharedDirectory(PluginConfigFactory cfg, @PluginName String pluginName)
       throws IOException {
     String sharedDirectory =
-        Strings.emptyToNull(cfg.getFromGerritConfig(pluginName, true).getString("sharedDirectory"));
+        Strings.emptyToNull(cfg.getFromGerritConfig(pluginName, true).getString(SHARED_DIRECTORY));
     if (sharedDirectory == null) {
-      throw new ProvisionException("sharedDirectory must be configured");
+      throw new ProvisionException(SHARED_DIRECTORY + " must be configured");
     }
     Path sharedDirectoryPath = Paths.get(sharedDirectory);
     Files.createDirectories(sharedDirectoryPath);
diff --git a/src/test/java/com/ericsson/gerrit/plugins/highavailability/ModuleTest.java b/src/test/java/com/ericsson/gerrit/plugins/highavailability/ModuleTest.java
index b92da94..ff7c614 100644
--- a/src/test/java/com/ericsson/gerrit/plugins/highavailability/ModuleTest.java
+++ b/src/test/java/com/ericsson/gerrit/plugins/highavailability/ModuleTest.java
@@ -14,6 +14,7 @@
 
 package com.ericsson.gerrit.plugins.highavailability;
 
+import static com.ericsson.gerrit.plugins.highavailability.Configuration.SHARED_DIRECTORY;
 import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.Mockito.when;
 
@@ -59,7 +60,7 @@
   @Test
   public void shouldReturnConfiguredSharedDirectory() throws IOException {
     File configuredDirectory = tempFolder.newFolder();
-    when(pluginConfigMock.getString("sharedDirectory"))
+    when(pluginConfigMock.getString(SHARED_DIRECTORY))
         .thenReturn(configuredDirectory.getAbsolutePath());
 
     Path sharedDirectory = module.getSharedDirectory(pluginConfigFactoryMock, PLUGIN_NAME);
@@ -70,7 +71,7 @@
   public void shouldCreateSharedDirectoryIfItDoesNotExist() throws IOException {
     File configuredDirectory = tempFolder.newFolder();
     assertThat(configuredDirectory.delete()).isTrue();
-    when(pluginConfigMock.getString("sharedDirectory"))
+    when(pluginConfigMock.getString(SHARED_DIRECTORY))
         .thenReturn(configuredDirectory.getAbsolutePath());
 
     Path sharedDirectory = module.getSharedDirectory(pluginConfigFactoryMock, PLUGIN_NAME);
@@ -80,7 +81,7 @@
   @Test(expected = IOException.class)
   public void shouldThrowAnExceptionIfAnErrorOccurCreatingSharedDirectory() throws IOException {
     File configuredDirectory = tempFolder.newFile();
-    when(pluginConfigMock.getString("sharedDirectory"))
+    when(pluginConfigMock.getString(SHARED_DIRECTORY))
         .thenReturn(configuredDirectory.getAbsolutePath());
 
     module.getSharedDirectory(pluginConfigFactoryMock, PLUGIN_NAME);