InvocationResult Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/util/LambdaSafe.java lines 389–446

	public static final class InvocationResult<R> {

		private static final InvocationResult<?> NONE = new InvocationResult<>(null);

		private final @Nullable R value;

		private InvocationResult(@Nullable R value) {
			this.value = value;
		}

		/**
		 * Return true if a result in present.
		 * @return if a result is present
		 */
		public boolean hasResult() {
			return this != NONE;
		}

		/**
		 * Return the result of the invocation or {@code null} if the callback wasn't
		 * suitable.
		 * @return the result of the invocation or {@code null}
		 */
		public @Nullable R get() {
			return this.value;
		}

		/**
		 * Return the result of the invocation or the given fallback if the callback
		 * wasn't suitable.
		 * @param fallback the fallback to use when there is no result
		 * @return the result of the invocation or the fallback
		 */
		public @Nullable R get(@Nullable R fallback) {
			return (this != NONE) ? this.value : fallback;
		}

		/**
		 * Create a new {@link InvocationResult} instance with the specified value.
		 * @param value the value (may be {@code null})
		 * @param <R> the result type
		 * @return an {@link InvocationResult}
		 */
		public static <R> InvocationResult<R> of(@Nullable R value) {
			return new InvocationResult<>(value);
		}

		/**
		 * Return an {@link InvocationResult} instance representing no result.
		 * @param <R> the result type
		 * @return an {@link InvocationResult}
		 */
		@SuppressWarnings("unchecked")
		public static <R> InvocationResult<R> noResult() {
			return (InvocationResult<R>) NONE;
		}

	}