BindResult Class — spring-boot Architecture

Source Code

core/spring-boot/src/main/java/org/springframework/boot/context/properties/bind/BindResult.java lines 39–158

public final class BindResult<T> {

	private static final BindResult<?> UNBOUND = new BindResult<>(null);

	private final @Nullable T value;

	private BindResult(@Nullable T value) {
		this.value = value;
	}

	/**
	 * Return the object that was bound or throw a {@link NoSuchElementException} if no
	 * value was bound.
	 * @return the bound value (never {@code null})
	 * @throws NoSuchElementException if no value was bound
	 * @see #isBound()
	 */
	public T get() throws NoSuchElementException {
		if (this.value == null) {
			throw new NoSuchElementException("No value bound");
		}
		return this.value;
	}

	/**
	 * Returns {@code true} if a result was bound.
	 * @return if a result was bound
	 */
	public boolean isBound() {
		return (this.value != null);
	}

	/**
	 * Invoke the specified consumer with the bound value, or do nothing if no value has
	 * been bound.
	 * @param consumer block to execute if a value has been bound
	 */
	public void ifBound(Consumer<? super T> consumer) {
		Assert.notNull(consumer, "'consumer' must not be null");
		if (this.value != null) {
			consumer.accept(this.value);
		}
	}

	/**
	 * Apply the provided mapping function to the bound value, or return an updated
	 * unbound result if no value has been bound.
	 * @param <U> the type of the result of the mapping function
	 * @param mapper a mapping function to apply to the bound value. The mapper will not
	 * be invoked if no value has been bound.
	 * @return an {@code BindResult} describing the result of applying a mapping function
	 * to the value of this {@code BindResult}.
	 */
	public <U> BindResult<U> map(Function<? super T, ? extends U> mapper) {
		Assert.notNull(mapper, "'mapper' must not be null");
		return of((this.value != null) ? mapper.apply(this.value) : null);
	}

	/**
	 * Return the object that was bound, or {@code other} if no value has been bound.
	 * @param other the value to be returned if there is no bound value (may be
	 * {@code null})
	 * @return the value, if bound, otherwise {@code other}
	 */
	@Contract("!null -> !null")
	public @Nullable T orElse(@Nullable T other) {
		return (this.value != null) ? this.value : other;
	}

	/**
	 * Return the object that was bound, or the result of invoking {@code other} if no
	 * value has been bound.
	 * @param other a {@link Supplier} of the value to be returned if there is no bound
	 * value
	 * @return the value, if bound, otherwise the supplied {@code other}
	 */
	public T orElseGet(Supplier<? extends T> other) {
		return (this.value != null) ? this.value : other.get();
	}

	/**
	 * Return the object that was bound, or throw an exception to be created by the
	 * provided supplier if no value has been bound.
	 * @param <X> the type of the exception to be thrown
	 * @param exceptionSupplier the supplier which will return the exception to be thrown
	 * @return the present value
	 * @throws X if there is no value present
	 */
	public <X extends Throwable> T orElseThrow(Supplier<? extends X> exceptionSupplier) throws X {
		if (this.value == null) {
			throw exceptionSupplier.get();
		}
		return this.value;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj) {
			return true;
		}
		if (obj == null || getClass() != obj.getClass()) {
			return false;
		}
		return ObjectUtils.nullSafeEquals(this.value, ((BindResult<?>) obj).value);
	}

	@Override
	public int hashCode() {
		return ObjectUtils.nullSafeHashCode(this.value);
	}

	@SuppressWarnings("unchecked")
	static <T> BindResult<T> of(@Nullable T value) {
		if (value == null) {
			return (BindResult<T>) UNBOUND;
		}
		return new BindResult<>(value);
	}

}