com.machinezoo.noexception.optional.OptionalToIntFunction Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of noexception Show documentation

Makes exception handling concise and beautiful, yet architecturally clean and flexible.

There is a newer version: 1.9.1

// Part of NoException: https://noexception.machinezoo.com
package com.machinezoo.noexception.optional;

import java.util.*;
import java.util.function.*;
import com.machinezoo.noexception.*;

/**
 * Variation of {@link ToIntFunction} that returns {@link OptionalInt} instead of the raw value.
 * {@code OptionalToIntFunction} is typically obtained from {@link ExceptionHandler#fromToIntFunction(ToIntFunction)},
 * in which case its return value is empty when the underlying {@code ToIntFunction} throws an exception.
 * See noexception tutorial.
 * 
 * @param 
 *            see {@link ToIntFunction}
 * @see ExceptionHandler#fromToIntFunction(ToIntFunction)
 * @see ToIntFunction
 */
@FunctionalInterface public interface OptionalToIntFunction extends Function {
	/**
	 * Variation of {@link ToIntFunction#applyAsInt(Object)} that returns {@link OptionalInt}.
	 * If this {@code OptionalToIntFunction} is obtained from {@link ExceptionHandler#fromToIntFunction(ToIntFunction)},
	 * the {@code OptionalInt} will be empty only if the underlying {@code ToIntFunction} throws.
	 * Otherwise the returned {@code OptionalInt} just wraps the return value of underlying {@code ToIntFunction}.
	 * 
	 * @param value
	 *            see {@link ToIntFunction#applyAsInt(Object)}
	 * @return {@code OptionalInt} typically wrapping return value of {@link ToIntFunction#applyAsInt(Object)},
	 *         or an empty {@code OptionalInt} (typically signifying an exception)
	 * @see ExceptionHandler#fromToIntFunction(ToIntFunction)
	 * @see ToIntFunction#applyAsInt(Object)
	 */
	@Override OptionalInt apply(T value);
	/**
	 * Convert this {@code OptionalToIntFunction} to plain {@code ToIntFunction} using default value.
	 * The returned {@code ToIntFunction} will unwrap present value from the {@code OptionalInt} if possible,
	 * or return {@code result} if the {@code OptionalInt} is empty.
	 * 
	 * @param result
	 *            default value to return instead of an empty {@code OptionalInt}
	 * @return plain {@code ToIntFunction} that either unwraps {@code OptionalInt} or returns default value
	 * @see #orElseGet(IntSupplier)
	 * @see OptionalInt#orElse(int)
	 */
	default ToIntFunction orElse(int result) {
		return new DefaultToIntFunction(this, result);
	}
	/**
	 * Convert this {@code OptionalToIntFunction} to plain {@code ToIntFunction} using fallback {@code IntSupplier}.
	 * The returned {@code ToIntFunction} will unwrap present value from the {@code OptionalInt} if possible,
	 * or fall back to calling {@code source} if the {@code OptionalInt} is empty.
	 * 
	 * @param source
	 *            {@code IntSupplier} to query for fallback value when {@code OptionalInt} is empty
	 * @return plain {@code ToIntFunction} that either unwraps {@code OptionalInt} or falls back to {@code source}
	 * @see #orElse(int)
	 * @see OptionalInt#orElseGet(IntSupplier)
	 */
	default ToIntFunction orElseGet(IntSupplier source) {
		return new FallbackToIntFunction(this, source);
	}
}