com.jongsoft.utils.control.Optional Maven / Gradle / Ivy
/*
* The MIT License
*
* Copyright 2016 Jong Soft.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package com.jongsoft.utils.control;
import com.jongsoft.utils.core.Mappable;
import com.jongsoft.utils.core.OrElse;
import com.jongsoft.utils.core.Value;
import java.util.Objects;
import java.util.function.Function;
import java.util.function.Supplier;
public interface Optional extends Value, Mappable, OrElse {
@Override
Optional map(Function mapper);
/**
* This method will provide the entity contained within the {@link Optional}, in case no entity
* is present the {@link Supplier} is called to create the else situation.
*
* @param supplier the supplier to create an entity of none is contained in the {@link Optional}
* @return either the contained entity or the created one using the {@link Supplier}
*/
T getOrSupply(Supplier supplier);
/**
* This method will return the contained entity within the {@link Optional}, in case no entity
* is present an exception will be thrown using the provided exceptionSupplier.
*
* @param exceptionSupplier the {@link Supplier} used to create the {@link Throwable}
* @param the type of the Throwable that will be thrown
* @return the entity contained within the {@link Optional}
* @throws X in case of no entity
* @throws NullPointerException in case the exceptionSupplier was null
*/
T getOrThrow(Supplier exceptionSupplier) throws X;
//----------------------------------------------------------------------------------------------
//-- All static helper methods to instantiate the Optional class
/**
* Creates a new {@link Optional} representing the provided value.
*
* This method will throw an {@link NullPointerException} when the provided value is null.
*
* @param the type of the value
* @param value the actual value
*
* @return an {@link Optional} representing the value
*/
static Optional of(T value) {
Objects.requireNonNull(value, "Value cannot be null");
return new OptionalSome<>(value);
}
/**
* Creates a new {@link Optional} representing the provided value.
*
* This method will allow null values.
*
* @param the type of the value
* @param value the actual value
*
* @return an {@link Optional} representing the value
*/
@SuppressWarnings("unchecked")
static Optional ofNullable(T value) {
return value != null
? new OptionalSome<>(value)
: (Optional) OptionalNone.NONE;
}
/**
* Creates a default empty {@link Optional}.
*
* @param the type of the value
* @return a default optional with a null value
*/
@SuppressWarnings("unchecked")
static Optional empty() {
return (Optional) OptionalNone.NONE;
}
}