OptionalInt (Java Platform SE 8 ) (original) (raw)
- java.util.OptionalInt
public final class OptionalInt
extends Object
A container object which may or may not contain a int
value. If a value is present, isPresent()
will return true
andgetAsInt()
will return the value.
Additional methods that depend on the presence or absence of a contained value are provided, such as orElse() (return a default value if value not present) andifPresent() (execute a block of code if the value is present).
This is a value-based class; use of identity-sensitive operations (including reference equality (==
), identity hash code, or synchronization) on instances ofOptionalInt
may have unpredictable results and should be avoided.
Since:
1.8
Method Summary
All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type Method Description static OptionalInt empty() Returns an empty OptionalInt instance. boolean equals(Object obj) Indicates whether some other object is "equal to" this OptionalInt. int getAsInt() If a value is present in this OptionalInt, returns the value, otherwise throws NoSuchElementException. int hashCode() Returns the hash code value of the present value, if any, or 0 (zero) if no value is present. void ifPresent(IntConsumer consumer) Have the specified consumer accept the value if a value is present, otherwise do nothing. boolean isPresent() Return true if there is a value present, otherwise false. static OptionalInt of(int value) Return an OptionalInt with the specified value present. int orElse(int other) Return the value if present, otherwise return other. int orElseGet(IntSupplier other) Return the value if present, otherwise invoke other and return the result of that invocation. <X extends Throwable>int orElseThrow(Supplier exceptionSupplier) Return the contained value, if present, otherwise throw an exception to be created by the provided supplier. String toString() Returns a string representation of the object. * ### Methods inherited from class java.lang.[Object](../../java/lang/Object.html "class in java.lang") `[clone](../../java/lang/Object.html#clone--), [finalize](../../java/lang/Object.html#finalize--), [getClass](../../java/lang/Object.html#getClass--), [notify](../../java/lang/Object.html#notify--), [notifyAll](../../java/lang/Object.html#notifyAll--), [wait](../../java/lang/Object.html#wait--), [wait](../../java/lang/Object.html#wait-long-), [wait](../../java/lang/Object.html#wait-long-int-)`
Method Detail
* #### empty public static [OptionalInt](../../java/util/OptionalInt.html "class in java.util") empty() Returns an empty `OptionalInt` instance. No value is present for this OptionalInt. API Note: Though it may be tempting to do so, avoid testing if an object is empty by comparing with `==` against instances returned by`Option.empty()`. There is no guarantee that it is a singleton. Instead, use [isPresent()](../../java/util/OptionalInt.html#isPresent--). Returns: an empty `OptionalInt` * #### of public static [OptionalInt](../../java/util/OptionalInt.html "class in java.util") of(int value) Return an `OptionalInt` with the specified value present. Parameters: `value` \- the value to be present Returns: an `OptionalInt` with the value present * #### getAsInt public int getAsInt() If a value is present in this `OptionalInt`, returns the value, otherwise throws `NoSuchElementException`. Returns: the value held by this `OptionalInt` Throws: `[NoSuchElementException](../../java/util/NoSuchElementException.html "class in java.util")` \- if there is no value present See Also: [isPresent()](../../java/util/OptionalInt.html#isPresent--) * #### isPresent public boolean isPresent() Return `true` if there is a value present, otherwise `false`. Returns: `true` if there is a value present, otherwise `false` * #### ifPresent public void ifPresent([IntConsumer](../../java/util/function/IntConsumer.html "interface in java.util.function") consumer) Have the specified consumer accept the value if a value is present, otherwise do nothing. Parameters: `consumer` \- block to be executed if a value is present Throws: `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if value is present and `consumer` is null * #### orElse public int orElse(int other) Return the value if present, otherwise return `other`. Parameters: `other` \- the value to be returned if there is no value present Returns: the value, if present, otherwise `other` * #### orElseGet public int orElseGet([IntSupplier](../../java/util/function/IntSupplier.html "interface in java.util.function") other) Return the value if present, otherwise invoke `other` and return the result of that invocation. Parameters: `other` \- a `IntSupplier` whose result is returned if no value is present Returns: the value if present otherwise the result of `other.getAsInt()` Throws: `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if value is not present and `other` is null * #### orElseThrow public <X extends [Throwable](../../java/lang/Throwable.html "class in java.lang")> int orElseThrow([Supplier](../../java/util/function/Supplier.html "interface in java.util.function")<X> exceptionSupplier) throws X Return the contained value, if present, otherwise throw an exception to be created by the provided supplier. API Note: A method reference to the exception constructor with an empty argument list can be used as the supplier. For example,`IllegalStateException::new` Type Parameters: `X` \- Type of the exception to be thrown Parameters: `exceptionSupplier` \- The supplier which will return the exception to be thrown Returns: the present value Throws: `X` \- if there is no value present `[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang")` \- if no value is present and`exceptionSupplier` is null `X extends [Throwable](../../java/lang/Throwable.html "class in java.lang")` * #### equals public boolean equals([Object](../../java/lang/Object.html "class in java.lang") obj) Indicates whether some other object is "equal to" this OptionalInt. The other object is considered equal if: * it is also an `OptionalInt` and; * both instances have no value present or; * the present values are "equal to" each other via `==`. Overrides: `[equals](../../java/lang/Object.html#equals-java.lang.Object-)` in class `[Object](../../java/lang/Object.html "class in java.lang")` Parameters: `obj` \- an object to be tested for equality Returns: {code true} if the other object is "equal to" this object otherwise `false` See Also: [Object.hashCode()](../../java/lang/Object.html#hashCode--), [HashMap](../../java/util/HashMap.html "class in java.util") * #### hashCode public int hashCode() Returns the hash code value of the present value, if any, or 0 (zero) if no value is present. Overrides: `[hashCode](../../java/lang/Object.html#hashCode--)` in class `[Object](../../java/lang/Object.html "class in java.lang")` Returns: hash code value of the present value or 0 if no value is present See Also: [Object.equals(java.lang.Object)](../../java/lang/Object.html#equals-java.lang.Object-), [System.identityHashCode(java.lang.Object)](../../java/lang/System.html#identityHashCode-java.lang.Object-) * #### toString public [String](../../java/lang/String.html "class in java.lang") toString() Returns a string representation of the object. In general, the`toString` method returns a string that "textually represents" this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method. The `toString` method for class `Object` returns a string consisting of the name of the class of which the object is an instance, the at-sign character \` `@`', and the unsigned hexadecimal representation of the hash code of the object. In other words, this method returns a string equal to the value of: > getClass().getName() + '@' + Integer.toHexString(hashCode()) > Returns a non-empty string representation of this object suitable for debugging. The exact presentation format is unspecified and may vary between implementations and versions. Overrides: `[toString](../../java/lang/Object.html#toString--)` in class `[Object](../../java/lang/Object.html "class in java.lang")` Implementation Requirements: If a value is present the result must include its string representation in the result. Empty and present instances must be unambiguously differentiable. Returns: the string representation of this instance
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