Merge pull request #7 from launchdarkly/jko/offline-mode

Add an offline mode that never talks to a remote server

src/main/java/com/launchdarkly/client/LDClient.java

@@ -42,6 +42,7 @@ public class LDClient implements Closeable {
   private final EventProcessor eventProcessor;
   private final String apiKey;
   protected static final String CLIENT_VERSION = getClientVersion();
+  private volatile boolean offline = false;
 
 
   /**
@@ -117,6 +118,9 @@ public void sendEvent(String eventName, LDUser user, JsonObject data) {
    * @param user the user that performed the event
    */
   public void sendEvent(String eventName, LDUser user) {
+    if (this.offline) {
+      return;
+    }
     sendEvent(eventName, user, null);
   }
 
@@ -138,6 +142,10 @@ private void sendFlagRequestEvent(String featureKey, LDUser user, boolean value)
    * @return whether or not the flag should be enabled, or {@code defaultValue} if the flag is disabled in the LaunchDarkly control panel
    */
   public boolean getFlag(String featureKey, LDUser user, boolean defaultValue) {
+    if (this.offline) {
+      return defaultValue;
+    }
+
     Gson gson = new Gson();
     HttpCacheContext context = HttpCacheContext.create();
     HttpGet request = config.getRequest(apiKey, "/api/eval/features/" + featureKey);
@@ -220,6 +228,32 @@ public void close() throws IOException {
   }
 
 
+  /**
+   * Puts the LaunchDarkly client in offline mode.
+   * In offline mode, all calls to {@link #getFlag(String, LDUser, boolean)} will return the default value, and
+   * {@link #sendEvent(String, LDUser, com.google.gson.JsonObject)} will be a no-op.
+   *
+   */
+  public void setOffline() {
+    this.offline = true;
+  }
+
+  /**
+   * Puts the LaunchDarkly client in online mode.
+   *
+   */
+  public void setOnline() {
+    this.offline = false;
+  }
+
+  /**
+   *
+   * @return whether the client is in offline mode
+   */
+  public boolean isOffline() {
+    return this.offline;
+  }
+
   private static String getClientVersion() {
     Class clazz = LDConfig.class;
     String className = clazz.getSimpleName() + ".class";