Package org.apache.commons.lang3

Class Functions

  • @Deprecated
public class Functions
extends java.lang.Object
    Deprecated.
    Use Failable.
    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 -> {
         try {
             m.invoke(o, args);
         } catch (Throwable t) {
             throw Functions.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:
    3.9

    • Constructor Detail

      • Functions

        public Functions()
        Deprecated.

    • Method Detail

      • accept

        public static <O1,​O2,​T extends java.lang.Throwable> void accept​(Functions.FailableBiConsumer<O1,​O2,​T> consumer,
                                                                            O1 object1,
                                                                            O2 object2)
        Deprecated.
        Consumes a consumer and rethrows any exception as a RuntimeException.
        Type Parameters:
        O1 - the type of the first argument the consumer accepts
        O2 - the type of the second argument the consumer accepts
        T - 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 <O,​T extends java.lang.Throwable> void accept​(Functions.FailableConsumer<O,​T> consumer,
                                                                  O object)
        Deprecated.
        Consumes a consumer and rethrows any exception as a RuntimeException.
        Type Parameters:
        O - the type the consumer accepts
        T - the type of checked exception the consumer may throw
        Parameters:
        consumer - the consumer to consume
        object - the object to consume by consumer

      • apply

        public static <O1,​O2,​O,​T extends java.lang.Throwable> O apply​(Functions.FailableBiFunction<O1,​O2,​O,​T> function,
                                                                                O1 input1,
                                                                                O2 input2)
        Deprecated.
        Applies a function and rethrows any exception as a RuntimeException.
        Type Parameters:
        O1 - the type of the first argument the function accepts
        O2 - the type of the second argument the function accepts
        O - the return type of the function
        T - 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 <I,​O,​T extends java.lang.Throwable> O apply​(Functions.FailableFunction<I,​O,​T> function,
                                                                      I input)
        Deprecated.
        Applies a function and rethrows any exception as a RuntimeException.
        Type Parameters:
        I - the type of the argument the function accepts
        O - the return type of the function
        T - 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

      • asBiConsumer

        public static <O1,​O2> java.util.function.BiConsumer<O1,​O2> asBiConsumer​(Functions.FailableBiConsumer<O1,​O2,​?> consumer)
        Deprecated.
        Converts the given Functions.FailableBiConsumer into a standard BiConsumer.
        Type Parameters:
        O1 - the type of the first argument of the consumers
        O2 - the type of the second argument of the consumers
        Parameters:
        consumer - a failable BiConsumer
        Returns:
        a standard BiConsumer
        Since:
        3.10

      • asBiFunction

        public static <O1,​O2,​O> java.util.function.BiFunction<O1,​O2,​O> asBiFunction​(Functions.FailableBiFunction<O1,​O2,​O,​?> function)
        Deprecated.
        Converts the given Functions.FailableBiFunction into a standard BiFunction.
        Type Parameters:
        O1 - the type of the first argument of the input of the functions
        O2 - the type of the second argument of the input of the functions
        O - the type of the output of the functions
        Parameters:
        function - a Functions.FailableBiFunction
        Returns:
        a standard BiFunction
        Since:
        3.10

      • asBiPredicate

        public static <O1,​O2> java.util.function.BiPredicate<O1,​O2> asBiPredicate​(Functions.FailableBiPredicate<O1,​O2,​?> predicate)
        Deprecated.
        Converts the given Functions.FailableBiPredicate into a standard BiPredicate.
        Type Parameters:
        O1 - the type of the first argument used by the predicates
        O2 - the type of the second argument used by the predicates
        Parameters:
        predicate - a Functions.FailableBiPredicate
        Returns:
        a standard BiPredicate
        Since:
        3.10

      • asFunction

        public static <I,​O> java.util.function.Function<I,​O> asFunction​(Functions.FailableFunction<I,​O,​?> function)
        Deprecated.
        Converts the given Functions.FailableFunction into a standard Function.
        Type Parameters:
        I - the type of the input of the functions
        O - the type of the output of the functions
        Parameters:
        function - a {code FailableFunction}
        Returns:
        a standard Function
        Since:
        3.10

      • call

        public static <O,​T extends java.lang.Throwable> O call​(Functions.FailableCallable<O,​T> callable)
        Deprecated.
        Calls a callable and rethrows any exception as a RuntimeException.
        Type Parameters:
        O - the return type of the callable
        T - 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 <O,​T extends java.lang.Throwable> O get​(Functions.FailableSupplier<O,​T> supplier)
        Deprecated.
        Invokes a supplier, and returns the result.
        Type Parameters:
        O - The suppliers output type.
        T - 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
        Since:
        3.10

      • rethrow

        public static java.lang.RuntimeException rethrow​(java.lang.Throwable throwable)
        Deprecated.
        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 <T extends java.lang.Throwable> void run​(Functions.FailableRunnable<T> runnable)
        Deprecated.
        Runs a runnable and rethrows any exception as a RuntimeException.
        Type Parameters:
        T - the type of checked exception the runnable may throw
        Parameters:
        runnable - The runnable to run

      • test

        public static <O1,​O2,​T extends java.lang.Throwable> boolean test​(Functions.FailableBiPredicate<O1,​O2,​T> predicate,
                                                                             O1 object1,
                                                                             O2 object2)
        Deprecated.
        Tests a predicate and rethrows any exception as a RuntimeException.
        Type Parameters:
        O1 - the type of the first argument the predicate tests
        O2 - the type of the second argument the predicate tests
        T - 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 <O,​T extends java.lang.Throwable> boolean test​(Functions.FailablePredicate<O,​T> predicate,
                                                                   O object)
        Deprecated.
        Tests a predicate and rethrows any exception as a RuntimeException.
        Type Parameters:
        O - the type of argument the predicate tests
        T - 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​(Functions.FailableRunnable<? extends java.lang.Throwable> action,
                                    Functions.FailableConsumer<java.lang.Throwable,​? extends java.lang.Throwable> errorHandler,
                                    Functions.FailableRunnable<? extends java.lang.Throwable>... resources)
        Deprecated.
        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 Functions.FailableRunnable, which will be executed.
        See Also:
        tryWithResources(FailableRunnable, FailableRunnable...)

      • tryWithResources

        @SafeVarargs
public static void tryWithResources​(Functions.FailableRunnable<? extends java.lang.Throwable> action,
                                    Functions.FailableRunnable<? extends java.lang.Throwable>... resources)
        Deprecated.
        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 Functions.FailableRunnable, which will be executed.
        See Also:
        tryWithResources(FailableRunnable, FailableConsumer, FailableRunnable...)