Example usage for Java com.google.common.base Optional fields, constructors, methods, implement or subclass
The text is from its open source code.
| Optional | absent() Returns an Optional instance with no contained reference. |
| Set | asSet() Returns an immutable singleton Set whose only element is the contained instance if it is present; an empty immutable Set otherwise. |
| boolean | equals(@Nullable Object object) Returns true if object is an Optional instance, and either the contained references are Object#equals equal to each other or both are absent. |
| Optional | fromNullable(@Nullable T nullableReference) If nullableReference is non-null, returns an Optional instance containing that reference; otherwise returns Optional#absent . |
| T | get() Returns the contained instance, which must be present. |
| int | hashCode() Returns a hash code for this instance. |
| boolean | isPresent() Returns true if this holder contains a (non-null) instance. |
| Optional | of(T reference) Returns an Optional instance containing the given non-null reference. |
| T | or(T defaultValue) Returns the contained instance if it is present; defaultValue otherwise. |
| Optional | or(Optional secondChoice) Returns this Optional if it has a value present; secondChoice otherwise. |
| T | or(Supplier supplier) Returns the contained instance if it is present; supplier.get() otherwise. |
| T | orNull() Returns the contained instance if it is present; null otherwise. |
| Iterable | presentInstances(final Iterable> optionals) Returns the value of each present instance from the supplied optionals , in order, skipping over occurrences of Optional#absent . |
| String | toString() Returns a string representation for this instance. |
| Optional | transform(Function function) If the instance is present, it is transformed with the given Function ; otherwise, Optional#absent is returned. |