Package org.apache.commons.lang3.function

Class Failable

java.lang.Object
org.apache.commons.lang3.function.Failable
public class Failable extends Object
This class provides utility functions, and classes for working with the java.util.function package, or more generally, with Java 8 lambdas. More specifically, it attempts to address the fact that lambdas are supposed not to throw Exceptions, at least not checked Exceptions, AKA instances of Exception. This enforces the use of constructs like: 

 Consumer<java.lang.reflect.Method> consumer = m -&gt; {
     try {
         m.invoke(o, args);
     } catch (Throwable t) {
         throw Failable.rethrow(t);
     }
 };

By replacing a Consumer<O> with a FailableConsumer<O,? extends Throwable>, this can be written like follows: 

 Functions.accept((m) -> m.invoke(o, args));

Obviously, the second version is much more concise and the spirit of Lambda expressions is met better than the second version.

Since:
3.11

  • Method Details

    • accept

      public static <T, U, E extends Throwable> void accept(FailableBiConsumer<T,U,E> consumer, T object1, U object2)
      Consumes a consumer and rethrows any exception as a RuntimeException.
      Type Parameters:
      T - the type of the first argument the consumer accepts
      U - the type of the second argument the consumer accepts
      E - the type of checked exception the consumer may throw
      Parameters:
      consumer - the consumer to consume
      object1 - the first object to consume by consumer
      object2 - the second object to consume by consumer

    • accept

      public static <T, E extends Throwable> void accept(FailableConsumer<T,E> consumer, T object)
      Consumes a consumer and rethrows any exception as a RuntimeException.
      Type Parameters:
      T - the type the consumer accepts
      E - the type of checked exception the consumer may throw
      Parameters:
      consumer - the consumer to consume
      object - the object to consume by consumer

    • accept

      public static <E extends Throwable> void accept(FailableDoubleConsumer<E> consumer, double value)
      Consumes a consumer and rethrows any exception as a RuntimeException.
      Type Parameters:
      E - the type of checked exception the consumer may throw
      Parameters:
      consumer - the consumer to consume
      value - the value to consume by consumer

    • accept

      public static <E extends Throwable> void accept(FailableIntConsumer<E> consumer, int value)
      Consumes a consumer and rethrows any exception as a RuntimeException.
      Type Parameters:
      E - the type of checked exception the consumer may throw
      Parameters:
      consumer - the consumer to consume
      value - the value to consume by consumer

    • accept

      public static <E extends Throwable> void accept(FailableLongConsumer<E> consumer, long value)
      Consumes a consumer and rethrows any exception as a RuntimeException.
      Type Parameters:
      E - the type of checked exception the consumer may throw
      Parameters:
      consumer - the consumer to consume
      value - the value to consume by consumer

    • apply

      public static <T, U, R, E extends Throwable> R apply(FailableBiFunction<T,U,R,E> function, T input1, U input2)
      Applies a function and rethrows any exception as a RuntimeException.
      Type Parameters:
      T - the type of the first argument the function accepts
      U - the type of the second argument the function accepts
      R - the return type of the function
      E - the type of checked exception the function may throw
      Parameters:
      function - the function to apply
      input1 - the first input to apply function on
      input2 - the second input to apply function on
      Returns:
      the value returned from the function

    • apply

      public static <T, R, E extends Throwable> R apply(FailableFunction<T,R,E> function, T input)
      Applies a function and rethrows any exception as a RuntimeException.
      Type Parameters:
      T - the type of the argument the function accepts
      R - the return type of the function
      E - the type of checked exception the function may throw
      Parameters:
      function - the function to apply
      input - the input to apply function on
      Returns:
      the value returned from the function

    • applyAsDouble

      public static <E extends Throwable> double applyAsDouble(FailableDoubleBinaryOperator<E> function, double left, double right)
      Applies a function and rethrows any exception as a RuntimeException.
      Type Parameters:
      E - the type of checked exception the function may throw
      Parameters:
      function - the function to apply
      left - the first input to apply function on
      right - the second input to apply function on
      Returns:
      the value returned from the function

    • asBiConsumer

      public static <T, U> BiConsumer<T,U> asBiConsumer(FailableBiConsumer<T,U,?> consumer)
      Converts the given FailableBiConsumer into a standard BiConsumer.
      Type Parameters:
      T - the type of the first argument of the consumers
      U - the type of the second argument of the consumers
      Parameters:
      consumer - a failable BiConsumer
      Returns:
      a standard BiConsumer

    • asBiFunction

      public static <T, U, R> BiFunction<T,U,R> asBiFunction(FailableBiFunction<T,U,R,?> function)
      Converts the given FailableBiFunction into a standard BiFunction.
      Type Parameters:
      T - the type of the first argument of the input of the functions
      U - the type of the second argument of the input of the functions
      R - the type of the output of the functions
      Parameters:
      function - a FailableBiFunction
      Returns:
      a standard BiFunction

    • asBiPredicate

      public static <T, U> BiPredicate<T,U> asBiPredicate(FailableBiPredicate<T,U,?> predicate)
      Converts the given FailableBiPredicate into a standard BiPredicate.
      Type Parameters:
      T - the type of the first argument used by the predicates
      U - the type of the second argument used by the predicates
      Parameters:
      predicate - a FailableBiPredicate
      Returns:
      a standard BiPredicate

    • asCallable

      public static <V> Callable<V> asCallable(FailableCallable<V,?> callable)
      Converts the given FailableCallable into a standard Callable.
      Type Parameters:
      V - the type used by the callables
      Parameters:
      callable - a FailableCallable
      Returns:
      a standard Callable

    • asConsumer

      public static <T> Consumer<T> asConsumer(FailableConsumer<T,?> consumer)
      Converts the given FailableConsumer into a standard Consumer.
      Type Parameters:
      T - the type used by the consumers
      Parameters:
      consumer - a FailableConsumer
      Returns:
      a standard Consumer

    • asFunction

      public static <T, R> Function<T,R> asFunction(FailableFunction<T,R,?> function)
      Converts the given FailableFunction into a standard Function.
      Type Parameters:
      T - the type of the input of the functions
      R - the type of the output of the functions
      Parameters:
      function - a {code FailableFunction}
      Returns:
      a standard Function

    • asPredicate

      public static <T> Predicate<T> asPredicate(FailablePredicate<T,?> predicate)
      Converts the given FailablePredicate into a standard Predicate.
      Type Parameters:
      T - the type used by the predicates
      Parameters:
      predicate - a FailablePredicate
      Returns:
      a standard Predicate

    • asRunnable

      public static Runnable asRunnable(FailableRunnable<?> runnable)
      Converts the given FailableRunnable into a standard Runnable.
      Parameters:
      runnable - a FailableRunnable
      Returns:
      a standard Runnable

    • asSupplier

      public static <T> Supplier<T> asSupplier(FailableSupplier<T,?> supplier)
      Converts the given FailableSupplier into a standard Supplier.
      Type Parameters:
      T - the type supplied by the suppliers
      Parameters:
      supplier - a FailableSupplier
      Returns:
      a standard Supplier

    • call

      public static <V, E extends Throwable> V call(FailableCallable<V,E> callable)
      Calls a callable and rethrows any exception as a RuntimeException.
      Type Parameters:
      V - the return type of the callable
      E - the type of checked exception the callable may throw
      Parameters:
      callable - the callable to call
      Returns:
      the value returned from the callable

    • get

      public static <T, E extends Throwable> T get(FailableSupplier<T,E> supplier)
      Invokes a supplier, and returns the result.
      Type Parameters:
      T - The suppliers output type.
      E - The type of checked exception, which the supplier can throw.
      Parameters:
      supplier - The supplier to invoke.
      Returns:
      The object, which has been created by the supplier

    • getAsBoolean

      public static <E extends Throwable> boolean getAsBoolean(FailableBooleanSupplier<E> supplier)
      Invokes a boolean supplier, and returns the result.
      Type Parameters:
      E - The type of checked exception, which the supplier can throw.
      Parameters:
      supplier - The boolean supplier to invoke.
      Returns:
      The boolean, which has been created by the supplier

    • getAsDouble

      public static <E extends Throwable> double getAsDouble(FailableDoubleSupplier<E> supplier)
      Invokes a double supplier, and returns the result.
      Type Parameters:
      E - The type of checked exception, which the supplier can throw.
      Parameters:
      supplier - The double supplier to invoke.
      Returns:
      The double, which has been created by the supplier

    • getAsInt

      public static <E extends Throwable> int getAsInt(FailableIntSupplier<E> supplier)
      Invokes an int supplier, and returns the result.
      Type Parameters:
      E - The type of checked exception, which the supplier can throw.
      Parameters:
      supplier - The int supplier to invoke.
      Returns:
      The int, which has been created by the supplier

    • getAsLong

      public static <E extends Throwable> long getAsLong(FailableLongSupplier<E> supplier)
      Invokes a long supplier, and returns the result.
      Type Parameters:
      E - The type of checked exception, which the supplier can throw.
      Parameters:
      supplier - The long supplier to invoke.
      Returns:
      The long, which has been created by the supplier

    • getAsShort

      public static <E extends Throwable> short getAsShort(FailableShortSupplier<E> supplier)
      Invokes a short supplier, and returns the result.
      Type Parameters:
      E - The type of checked exception, which the supplier can throw.
      Parameters:
      supplier - The short supplier to invoke.
      Returns:
      The short, which has been created by the supplier

    • rethrow

      public static RuntimeException rethrow(Throwable throwable)
      Rethrows a Throwable as an unchecked exception. If the argument is already unchecked, namely a RuntimeException or Error then the argument will be rethrown without modification. If the exception is IOException then it will be wrapped into a UncheckedIOException. In every other cases the exception will be wrapped into a UndeclaredThrowableException

      Note that there is a declared return type for this method, even though it never returns. The reason for that is to support the usual pattern: 

       throw rethrow(myUncheckedException);

      instead of just calling the method. This pattern may help the Java compiler to recognize that at that point an exception will be thrown and the code flow analysis will not demand otherwise mandatory commands that could follow the method call, like a return statement from a value returning method.

      Parameters:
      throwable - The throwable to rethrow possibly wrapped into an unchecked exception
      Returns:
      Never returns anything, this method never terminates normally.

    • run

      public static <E extends Throwable> void run(FailableRunnable<E> runnable)
      Runs a runnable and rethrows any exception as a RuntimeException.
      Type Parameters:
      E - the type of checked exception the runnable may throw
      Parameters:
      runnable - The runnable to run

    • stream

      public static <E> Streams.FailableStream<E> stream(Collection<E> collection)
      Converts the given collection into a Streams.FailableStream. The Streams.FailableStream consists of the collections elements. Shortcut for 
       Functions.stream(collection.stream());
      Type Parameters:
      E - The collections element type. (In turn, the result streams element type.)
      Parameters:
      collection - The collection, which is being converted into a Streams.FailableStream.
      Returns:
      The created Streams.FailableStream.

    • stream

      public static <T> Streams.FailableStream<T> stream(Stream<T> stream)
      Converts the given stream into a Streams.FailableStream. The Streams.FailableStream consists of the same elements, than the input stream. However, failable lambdas, like FailablePredicate, FailableFunction, and FailableConsumer may be applied, rather than Predicate, Function, Consumer, etc.
      Type Parameters:
      T - The streams element type.
      Parameters:
      stream - The stream, which is being converted into a Streams.FailableStream.
      Returns:
      The created Streams.FailableStream.

    • test

      public static <T, U, E extends Throwable> boolean test(FailableBiPredicate<T,U,E> predicate, T object1, U object2)
      Tests a predicate and rethrows any exception as a RuntimeException.
      Type Parameters:
      T - the type of the first argument the predicate tests
      U - the type of the second argument the predicate tests
      E - the type of checked exception the predicate may throw
      Parameters:
      predicate - the predicate to test
      object1 - the first input to test by predicate
      object2 - the second input to test by predicate
      Returns:
      the boolean value returned by the predicate

    • test

      public static <T, E extends Throwable> boolean test(FailablePredicate<T,E> predicate, T object)
      Tests a predicate and rethrows any exception as a RuntimeException.
      Type Parameters:
      T - the type of argument the predicate tests
      E - the type of checked exception the predicate may throw
      Parameters:
      predicate - the predicate to test
      object - the input to test by predicate
      Returns:
      the boolean value returned by the predicate

    • tryWithResources

      @SafeVarargs public static void tryWithResources(FailableRunnable<? extends Throwable> action, FailableConsumer<Throwable,? extends Throwable> errorHandler, FailableRunnable<? extends Throwable>... resources)
      A simple try-with-resources implementation, that can be used, if your objects do not implement the AutoCloseable interface. The method executes the action. The method guarantees, that all the resources are being executed, in the given order, afterwards, and regardless of success, or failure. If either the original action, or any of the resource action fails, then the first failure (AKA Throwable) is rethrown. Example use: 
      
 final FileInputStream fis = new FileInputStream("my.file");
 Functions.tryWithResources(useInputStream(fis), null, () -> fis.close());
      Parameters:
      action - The action to execute. This object will always be invoked.
      errorHandler - An optional error handler, which will be invoked finally, if any error occurred. The error handler will receive the first error, AKA Throwable.
      resources - The resource actions to execute. All resource actions will be invoked, in the given order. A resource action is an instance of FailableRunnable, which will be executed.
      See Also:

    • tryWithResources

      @SafeVarargs public static void tryWithResources(FailableRunnable<? extends Throwable> action, FailableRunnable<? extends Throwable>... resources)
      A simple try-with-resources implementation, that can be used, if your objects do not implement the AutoCloseable interface. The method executes the action. The method guarantees, that all the resources are being executed, in the given order, afterwards, and regardless of success, or failure. If either the original action, or any of the resource action fails, then the first failure (AKA Throwable) is rethrown. Example use: 
      
 final FileInputStream fis = new FileInputStream("my.file");
 Functions.tryWithResources(useInputStream(fis), () -> fis.close());
      Parameters:
      action - The action to execute. This object will always be invoked.
      resources - The resource actions to execute. All resource actions will be invoked, in the given order. A resource action is an instance of FailableRunnable, which will be executed.
      See Also: