some accounts classes refactorings

service/src/main/java/org/whispersystems/textsecuregcm/util/ExceptionUtils.java

@@ -0,0 +1,40 @@
+package org.whispersystems.textsecuregcm.util;
+
+import java.util.concurrent.CompletionException;
+
+public final class ExceptionUtils {
+
+  private ExceptionUtils() {
+    // utility class
+  }
+  
+  /**
+   * Extracts the cause of a {@link CompletionException}. If the given {@code throwable} is a
+   * {@code CompletionException}, this method will recursively iterate through its causal chain until it finds the first
+   * cause that is not a {@code CompletionException}. If the last {@code CompletionException} in the causal chain has a
+   * {@code null} cause, then this method returns the last {@code CompletionException} in the chain. If the given
+   * {@code throwable} is not a {@code CompletionException}, then this method returns the original {@code throwable}.
+   *
+   * @param throwable the throwable to "unwrap"
+   *
+   * @return the first entity in the given {@code throwable}'s causal chain that is not a {@code CompletionException}
+   */
+  public static Throwable unwrap(Throwable throwable) {
+    while (throwable instanceof CompletionException e && throwable.getCause() != null) {
+      throwable = e.getCause();
+    }
+    return throwable;
+  }
+
+  /**
+   * Wraps the given {@code throwable} in a {@link CompletionException} unless the given {@code throwable} is alreadt
+   * a {@code CompletionException}, in which case this method returns the original throwable.
+   *
+   * @param throwable the throwable to wrap in a {@code CompletionException}
+   */
+  public static CompletionException wrap(final Throwable throwable) {
+    return throwable instanceof CompletionException completionException
+        ? completionException
+        : new CompletionException(throwable);
+  }
+}

service/src/main/java/org/whispersystems/textsecuregcm/util/SystemMapper.java

@@ -10,20 +10,25 @@ import com.fasterxml.jackson.annotation.PropertyAccessor;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import javax.annotation.Nonnull;
 
 public class SystemMapper {
 
-  private static final ObjectMapper mapper = new ObjectMapper();
+  private static final ObjectMapper MAPPER = build();
 
-  static {
+
+  @Nonnull
+  public static ObjectMapper getMapper() {
+    return MAPPER;
+  }
+
+  @Nonnull
+  private static ObjectMapper build() {
+    final ObjectMapper mapper = new ObjectMapper();
     mapper.setVisibility(PropertyAccessor.ALL, JsonAutoDetect.Visibility.NONE);
     mapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
     mapper.registerModule(new JavaTimeModule());
     mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
-  }
-
-  public static ObjectMapper getMapper() {
     return mapper;
   }
-
 }