Added Result of optional method

Author: James-OpenGamma

modules/collect/src/main/java/com/opengamma/strata/collect/result/Result.java

@@ -460,6 +460,49 @@ public static <R> Result<R> ofNullable(R value) {
     return ofNullable(value, FailureReason.MISSING_DATA, "Found null where a value was expected");
   }
 
+  /**
+   * Returns a success result containing the value is present, else returns a failure result
+   * with the specified reason and message.
+   * <p>
+   * The message is produced using a template that contains zero to many "{}" placeholders.
+   * Each placeholder is replaced by the next available argument.
+   * If there are too few arguments, then the message will be left with placeholders.
+   * If there are too many arguments, then the excess arguments are appended to the
+   * end of the message. No attempt is made to format the arguments.
+   * See {@link Messages#format(String, Object...)} for more details.
+   *
+   * @param <R> the expected type of the result
+   * @param value  the potentially null value
+   * @param reason  the reason for the failure
+   * @param message  a message explaining the failure, uses "{}" for inserting {@code messageArgs}
+   * @param messageArgs  the arguments for the message
+   * @return a success result if the value is non-null, else a failure result
+   */
+  public static <R> Result<R> ofOptional(
+      Optional<R> value,
+      FailureReason reason,
+      String message,
+      Object... messageArgs) {
+
+    return value
+        .map(Result::success)
+        .orElse(Result.failure(reason, message, messageArgs));
+  }
+
+  /**
+   * Returns a success result containing the value is present, else returns a failure result
+   * with a reason of {@link FailureReason#MISSING_DATA} and message to say an unexpected empty value was found.
+   *
+   * @param <R> the expected type of the result
+   * @param value  the potentially null value
+   * @return a success result if the value is non-null, else a failure result
+   */
+  public static <R> Result<R> ofOptional(
+      Optional<R> value) {
+
+    return ofOptional(value, FailureReason.MISSING_DATA, "Found empty where a value was expected");
+  }
+
   //-------------------------------------------------------------------------
   /**
    * Checks if all the results are successful.

modules/collect/src/test/java/com/opengamma/strata/collect/result/ResultTest.java

@@ -18,6 +18,7 @@
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Optional;
 import java.util.Set;
 import java.util.function.BiFunction;
 import java.util.function.Function;
@@ -424,6 +425,29 @@ public void ofNullable_null() {
   }
 
   //-------------------------------------------------------------------------
+
+  @Test
+  public void ofOptional_nonEmpty() {
+    Result<Integer> test = Result.ofOptional(Optional.of(6));
+    assertThat(test.isFailure()).isFalse();
+    assertThat(test.getValue().intValue()).isEqualTo(6);
+  }
+
+  @Test
+  public void ofOptional_empty() {
+    Result<Integer> test = Result.ofOptional(Optional.empty());
+    assertThat(test.isFailure()).isTrue();
+    assertThat(test.getFailure().getMessage()).isEqualTo("Found empty where a value was expected");
+    assertThat(test.getFailure().getItems().size()).isEqualTo(1);
+    FailureItem item = test.getFailure().getItems().iterator().next();
+    assertThat(item.getReason()).isEqualTo(MISSING_DATA);
+    assertThat(item.getMessage()).isEqualTo("Found empty where a value was expected");
+    assertThat(item.getCauseType().isPresent()).isEqualTo(false);
+    assertThat(item.getStackTrace()).isNotNull();
+  }
+
+  //-------------------------------------------------------------------------
+
   @Test
   public void of_with_success() {