We need a whole WithFilter class to honor the "doesn't create a new collection" contract even though it seems unlikely to matter much in a collection with max size 1.
Test two objects for inequality.
Test two objects for inequality.
true if !(this == that), false otherwise.
Equivalent to x.hashCode except for boxed numeric types and null.
Equivalent to x.hashCode except for boxed numeric types and null.
For numerics, it returns a hash value which is consistent
with value equality: if two value type instances compare
as true, then ## will produce the same hash value for each
of them.
For null returns a hashcode where null.hashCode throws a
NullPointerException.
a hash value consistent with ==
Test two objects for equality.
Test two objects for equality.
The expression x == that is equivalent to if (x eq null) that eq null else x.equals(that).
true if the receiver object is equivalent to the argument; false otherwise.
Cast the receiver object to be of type T0.
Cast the receiver object to be of type T0.
Note that the success of a cast at runtime is modulo Scala's erasure semantics.
Therefore the expression 1.asInstanceOf[String] will throw a ClassCastException at
runtime, while the expression List(1).asInstanceOf[List[String]] will not.
In the latter example, because the type argument is erased as part of compilation it is
not possible to check whether the contents of the list are of the requested type.
the receiver object.
if the receiver object is not an instance of the erasure of type T0.
Create a copy of the receiver object.
Returns a Some containing the result of
applying pf to this Option's contained
value, if this option is
nonempty and pf is defined for that value.
Tests whether the argument (arg0) is a reference to the receiver object (this).
Tests whether the argument (arg0) is a reference to the receiver object (this).
The eq method implements an equivalence relation on
non-null instances of AnyRef, and has three additional properties:
x and y of type AnyRef, multiple invocations of
x.eq(y) consistently returns true or consistently returns false.x of type AnyRef, x.eq(null) and null.eq(x) returns false.null.eq(null) returns true. When overriding the equals or hashCode methods, it is important to ensure that their behavior is
consistent with reference equality. Therefore, if two objects are references to each other (o1 eq o2), they
should be equal to each other (o1 == o2) and they should hash to the same value (o1.hashCode == o2.hashCode).
true if the argument is a reference to the receiver object; false otherwise.
The equality method for reference types.
Returns true if this option is nonempty and the predicate
p returns true when applied to this Option's value.
Returns this Option if it is nonempty and applying the predicate p to
this Option's value returns true.
Returns this Option if it is nonempty and applying the predicate p to
this Option's value returns false.
Called by the garbage collector on the receiver object when there are no more references to the object.
Called by the garbage collector on the receiver object when there are no more references to the object.
The details of when and if the finalize method is invoked, as
well as the interaction between finalize and non-local returns
and exceptions, are all platform dependent.
Returns the result of applying f to this Option's value if
this Option is nonempty.
Returns true if this option is empty or the predicate
p returns true when applied to this Option's value.
Apply the given procedure f to the option's value,
if it is nonempty.
Returns the option's value.
A representation that corresponds to the dynamic class of the receiver object.
A representation that corresponds to the dynamic class of the receiver object.
The nature of the representation is platform dependent.
a representation that corresponds to the dynamic class of the receiver object.
not specified by SLS as a member of AnyRef
Returns the option's value if the option is nonempty, otherwise
return the result of evaluating default.
Returns true if the option is an instance of Some, false otherwise.
Returns true if the option is None, false otherwise.
Test whether the dynamic type of the receiver object is T0.
Test whether the dynamic type of the receiver object is T0.
Note that the result of the test is modulo Scala's erasure semantics.
Therefore the expression 1.isInstanceOf[String] will return false, while the
expression List(1).isInstanceOf[List[String]] will return true.
In the latter example, because the type argument is erased as part of compilation it is
not possible to check whether the contents of the list are of the specified type.
true if the receiver object is an instance of erasure of type T0; false otherwise.
Returns a singleton iterator returning the Option's value if it is nonempty, or an empty iterator if the option is empty.
Returns a Some containing the result of applying f to this Option's
value if this Option is nonempty.
Equivalent to !(this eq that).
Equivalent to !(this eq that).
true if the argument is not a reference to the receiver object; false otherwise.
Returns false if the option is None, true otherwise.
Returns false if the option is None, true otherwise.
Implemented here to avoid the implicit conversion to Iterable.
Wakes up a single thread that is waiting on the receiver object's monitor.
Wakes up a single thread that is waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
Wakes up all threads that are waiting on the receiver object's monitor.
Wakes up all threads that are waiting on the receiver object's monitor.
not specified by SLS as a member of AnyRef
Returns this Option if it is nonempty,
otherwise return the result of evaluating alternative.
Returns the option's value if it is nonempty,
or null if it is empty.
Returns the option's value if it is nonempty,
or null if it is empty.
Although the use of null is discouraged, code written to use
Option must often interface with code that expects and returns nulls.
Returns a Right containing the given
argument right if this is empty, or
a Left containing this Option's value
if this Option is nonempty.
Returns a singleton list containing the Option's value if it is nonempty, or the empty list if the Option is empty.
Returns a Left containing the given
argument left if this Option is empty, or
a Right containing this Option's value if
this is nonempty.
Necessary to keep Option from being implicitly converted to
Iterable in for comprehensions.
This case object represents non-existent values.
1.0, 16/07/2003