Java tutorial

Functional API

Functional interfaces provide target types for lambda expressions and method references.

There are base interfaces.

  1. The Supplier interface allows provide some values. (see list of suppliers)
  2. The Function interface allows to accept one argument and produce a result. (see list of functions)
  3. Operators are specialization of Function interface, when argument(s) and result have same type. (see list of operators)
  4. The Predicate interface allows to return a boolean value from an argument value, used to test values. (see list of predicates)
  5. The Consumer interface represents an operation that accepts a single input argument and returns no result. Unlike most other functional interfaces, Consumer is expected to operate via side-effects. (see list of consumers)

suppliers

interfacedescription
Supplier Represents a supplier of results.
BooleanSupplier Represents a supplier of boolean-valued results.
IntSupplier Represents a supplier of int-valued results.
LongSupplier Represents a supplier of long-valued results.
DoubleSupplier Represents a supplier of double-valued results.

functions

interfacedescription
Function Represents a function that accepts one argument and produces a result.
IntFunction Represents a function that accepts an int-valued argument and produces a result.
LongFunction Represents a function that accepts an long-valued argument and produces a result.
DoubleFunction Represents a function that accepts an double-valued argument and produces a result.
ToIntFunction Represents a function that produces an int-valued result.
ToLongFunction Represents a function that produces an long-valued result.
ToDoubleFunction Represents a function that produces an double-valued result.
IntToLongFunction Represents a function that accepts a int-valued argument and produces an long-valued result.
IntToDoubleFunction Represents a function that accepts a int-valued argument and produces an double-valued result.
LongToIntFunction Represents a function that accepts a long-valued argument and produces an int-valued result.
LongToDoubleFunction Represents a function that accepts a long-valued argument and produces an double-valued result.
DoubleToIntFunction Represents a function that accepts a double-valued argument and produces an int-valued result.
DoubleToLongFunction Represents a function that accepts a double-valued argument and produces an long-valued result.
BiFunction Represents a function that accepts two arguments and produces a result.
ToIntBiFunction Represents a function that accepts two arguments and produces a int-valued result.
ToLongBiFunction Represents a function that accepts two arguments and produces a long-valued result.
ToDoubleBiFunction Represents a function that accepts two arguments and produces a double-valued result.

operators

interfacedescription
UnaryOperator Represents an operation on a single operand that produces a result of the same type as its operand.
IntUnaryOperator Represents an operation on a single int-valued operand that produces an int-valued result.
LongUnaryOperator Represents an operation on a single long-valued operand that produces an long-valued result.
DoubleUnaryOperator Represents an operation on a single double-valued operand that produces an double-valued result.
BinaryOperator Represents an operation upon two operands of the same type, producing a result of the same type as the operands.
IntBinaryOperator Represents an operation upon two int-valued operands and producing an int-valued result.
LongBinaryOperator Represents an operation upon two long-valued operands and producing an long-valued result.
DoubleBinaryOperator Represents an operation upon two double-valued operands and producing an double-valued result.

predicates

interfacedescription
Predicate Represents a predicate of one argument.
IntPredicate Represents a predicate of one int-valued argument.
LongPredicate Represents a predicate of one long-valued argument.
DoublePredicate Represents a predicate of one double-valued argument.
BiPredicate Represents a predicate of two arguments.

consumers

interfacedescription
Consumer Represents an operation that accepts a single input argument and returns no result.
DoubleConsumer Represents an operation that accepts a single double-valued argument and returns no result.
IntConsumer Represents an operation that accepts a single int-valued argument and returns no result.
LongConsumer Represents an operation that accepts a single long-valued argument and returns no result.
BiConsumer Represents an operation that accepts two input arguments and returns no result.
ObjDoubleConsumer Represents an operation that accepts an object-valued and a double-valued argument, and returns no result.
ObjIntConsumer Represents an operation that accepts an object-valued and a int-valued argument, and returns no result.
ObjLongConsumer Represents an operation that accepts an object-valued and a long-valued argument, and returns no result.