ratpack.func

Interface Action<T>

Type Parameters:

T - The type of thing.

All Known Subinterfaces:

Fulfillment<T>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface Action<T>

A generic type for an object that does some work with a thing.

This type serves the same purpose as the JDK's Consumer, but allows throwing checked exceptions. It contains methods for bridging to and from the JDK type.

Method Summary

Modifier and Type	Method and Description
void	execute(T t) Executes the action against the given thing.
static <T> Action<T>	from(Consumer<T> consumer) Creates an action from a JDK consumer.
static <T> Action<T>	ignoreArg(NoArgAction noArgAction)
static <T> Action<T>	join(Action<? super T>... actions) Returns a new action that executes the given actions in order.
static Action<Object>	noop() Returns an action that does precisely nothing.
static <T> Action<? super T>	noopIfNull(Action<T> action) If the given action is null, returns noop(), otherwise returns the given action.
static Action<Throwable>	throwException() Returns an action that receives a throwable and immediately throws it.
static <T> Action<T>	throwException(Throwable throwable) Returns an action that immediately throws the given exception.
default Consumer<T>	toConsumer() Creates a JDK Consumer from this action.
static <T> T	with(T t, Action<? super T> action) Executes the action with the given argument, then returns the argument.

Method Detail

noop

static Action<Object> noop()

Returns an action that does precisely nothing.

Returns:

an action that does precisely nothing

noopIfNull

static <T> Action<? super T> noopIfNull(@Nullable
                                        Action<T> action)

If the given action is null, returns noop(), otherwise returns the given action.

Type Parameters:

T - the type of parameter received by the action

Parameters:

action - an action, maybe null.

Returns:

the given action param if it is not null, else a noop().

join

@SafeVarargs
static <T> Action<T> join(Action<? super T>... actions)

Returns a new action that executes the given actions in order.

Type Parameters:

T - the type of object the action accepts

Parameters:

actions - the actions to join into one action

Returns:

the newly created aggregate action

throwException

static Action<Throwable> throwException()

Returns an action that receives a throwable and immediately throws it.

Returns:

an action that receives a throwable and immediately throws it

throwException

static <T> Action<T> throwException(Throwable throwable)

Returns an action that immediately throws the given exception.

The exception is thrown via ExceptionUtils.toException(Throwable)

Type Parameters:

T - the argument type (anything, as the argument is ignored)

Parameters:

throwable - the throwable to immediately throw when the returned action is executed

Returns:

an action that immediately throws the given exception.

ignoreArg

static <T> Action<T> ignoreArg(NoArgAction noArgAction)

with

static <T> T with(T t,
                  Action<? super T> action)
           throws Exception

Executes the action with the given argument, then returns the argument.

import ratpack.func.Action;
 import java.util.ArrayList;

 public class Example {
   public static void main(String... args) throws Exception {
     assert Action.with(new ArrayList<>(), list -> list.add("foo")).get(0).equals("foo");
   }
 }
 

Type Parameters:

T - the type of the argument

Parameters:

t - the argument to execute the given action with

action - the action to execute with the given argument

Returns:

the given argument (i.e. t)

Throws:

Exception - any thrown by action

execute

void execute(T t)
      throws Exception

Executes the action against the given thing.

Parameters:

t - the thing to execute the action against

Throws:

Exception - if anything goes wrong

toConsumer

default Consumer<T> toConsumer()

Creates a JDK Consumer from this action.

Any exceptions thrown by this action will be unchecked via ExceptionUtils.uncheck(Throwable) and rethrown.

Returns:

this function as a JDK style consumer.

from

static <T> Action<T> from(Consumer<T> consumer)

Creates an action from a JDK consumer.

Type Parameters:

T - the type of object this action accepts

Parameters:

consumer - the JDK consumer

Returns:

the given consumer as an action