[LANG-1568]

org.apache.commons.lang3.function.FailableBiFunction.andThen(FailableFunction<?
super R, ? extends V, E>)
This commit is contained in:
Gary Gregory 2020-06-24 18:25:47 -04:00
parent 4badcde7f7
commit c7aea90a7a
4 changed files with 88 additions and 16 deletions

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@ -37,7 +37,7 @@ public interface FailableBiConsumer<T, U, E extends Throwable> {
/**
* Returns The NOP singleton.
*
*
* @param <T> Consumed type 1.
* @param <U> Consumed type 2.
* @param <E> Thrown exception.
@ -62,9 +62,9 @@ public interface FailableBiConsumer<T, U, E extends Throwable> {
* @param after the operation to perform after this one.
* @return a composed {@code FailableBiConsumer} like {@link BiConsumer#andThen(BiConsumer)}.
* @throws E Thrown when a consumer fails.
* @throws NullPointerException if {@code after} is null
* @throws NullPointerException if {@code after} is null.
*/
default FailableBiConsumer<T, U, E> andThen(FailableBiConsumer<? super T, ? super U, E> after) throws E {
default FailableBiConsumer<T, U, E> andThen(final FailableBiConsumer<? super T, ? super U, E> after) throws E {
Objects.requireNonNull(after);
return (t, u) -> {

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@ -17,7 +17,9 @@
package org.apache.commons.lang3.function;
import java.util.Objects;
import java.util.function.BiFunction;
import java.util.function.Function;
/**
* A functional interface like {@link BiFunction} that declares a {@code Throwable}.
@ -31,6 +33,37 @@ import java.util.function.BiFunction;
@FunctionalInterface
public interface FailableBiFunction<T, U, R, E extends Throwable> {
/** NOP singleton */
@SuppressWarnings("rawtypes")
final FailableBiFunction NOP = (t, u) -> null;
/**
* Returns The NOP singleton.
*
* @param <T> Consumed type 1.
* @param <U> Consumed type 2.
* @param <R> Return type.
* @param <E> Thrown exception.
* @return The NOP singleton.
*/
static <T, U, R, E extends Throwable> FailableBiFunction<T, U, R, E> nop() {
return NOP;
}
/**
* Returns a composed {@code FailableBiFunction} that like {@link BiFunction#andThen(Function)}.
*
* @param <V> the type of output of the {@code after} function, and of the composed function
* @param after the operation to perform after this one.
* @return a composed {@code FailableBiFunction} that like {@link BiFunction#andThen(Function)}.
* @throws E Thrown when a consumer fails.
* @throws NullPointerException if after is null.
*/
default <V> FailableBiFunction<T, U, V, E> andThen(final FailableFunction<? super R, ? extends V, E> after) throws E {
Objects.requireNonNull(after);
return (final T t, final U u) -> after.apply(apply(t, u));
}
/**
* Applies this function.
*

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@ -30,6 +30,22 @@ import java.util.function.Function;
@FunctionalInterface
public interface FailableFunction<T, R, E extends Throwable> {
/** NOP singleton */
@SuppressWarnings("rawtypes")
final FailableFunction NOP = t -> null;
/**
* Returns The NOP singleton.
*
* @param <T> Consumed type 1.
* @param <R> Return type.
* @param <E> Thrown exception.
* @return The NOP singleton.
*/
static <T, R, E extends Throwable> FailableFunction<T, R, E> nop() {
return NOP;
}
/**
* Applies this function.
*

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@ -45,9 +45,6 @@ import org.junit.jupiter.api.Test;
*/
public class FailableFunctionsTest {
private static final IllegalStateException ILLEGAL_STATE_EXCEPTION = new IllegalStateException();
private static final OutOfMemoryError ERROR = new OutOfMemoryError();
public static class CloseableObject {
private boolean closed;
@ -69,7 +66,6 @@ public class FailableFunctionsTest {
}
}
}
public static class FailureOnOddInvocations {
private static int invocations;
@ -268,10 +264,15 @@ public class FailableFunctionsTest {
}
}
private static final OutOfMemoryError ERROR = new OutOfMemoryError();
private static final IllegalStateException ILLEGAL_STATE_EXCEPTION = new IllegalStateException();
@Test
void testAcceptBiConsumer() {
final Testable<?, ?> testable = new Testable<>(null);
Throwable e = assertThrows(IllegalStateException.class, () -> Failable.accept(Testable::test, testable, ILLEGAL_STATE_EXCEPTION));
Throwable e = assertThrows(IllegalStateException.class,
() -> Failable.accept(Testable::test, testable, ILLEGAL_STATE_EXCEPTION));
assertSame(ILLEGAL_STATE_EXCEPTION, e);
e = assertThrows(OutOfMemoryError.class, () -> Failable.accept(Testable::test, testable, ERROR));
@ -632,28 +633,27 @@ public class FailableFunctionsTest {
t.setThrowable(th);
t.test();
};
Throwable e;
final FailableBiConsumer<Testable<?, ?>, Throwable, Throwable> nop = FailableBiConsumer.nop();
e = assertThrows(OutOfMemoryError.class, () -> nop.andThen(failableBiConsumer).accept(testable, ERROR));
final Throwable e = assertThrows(OutOfMemoryError.class,
() -> nop.andThen(failableBiConsumer).accept(testable, ERROR));
assertSame(ERROR, e);
// Does not throw
nop.andThen(nop);
// Documented in Javadoc edge-case.
assertThrows(NullPointerException.class, () -> failableBiConsumer.andThen(null));
}
@Test
public void testBiFunction() {
final IllegalStateException ise = ILLEGAL_STATE_EXCEPTION;
final Testable<?, ?> testable = new Testable<>(ise);
final Testable<?, ?> testable = new Testable<>(ILLEGAL_STATE_EXCEPTION);
final FailableBiFunction<Testable<?, ?>, Throwable, Integer, Throwable> failableBiFunction = (t, th) -> {
t.setThrowable(th);
return Integer.valueOf(t.testAsInteger());
return t.testAsInteger();
};
final BiFunction<Testable<?, ?>, Throwable, Integer> biFunction = Failable.asBiFunction(failableBiFunction);
Throwable e = assertThrows(IllegalStateException.class, () -> biFunction.apply(testable, ise));
assertSame(ise, e);
Throwable e = assertThrows(IllegalStateException.class,
() -> biFunction.apply(testable, ILLEGAL_STATE_EXCEPTION));
assertSame(ILLEGAL_STATE_EXCEPTION, e);
testable.setThrowable(ERROR);
e = assertThrows(OutOfMemoryError.class, () -> biFunction.apply(testable, ERROR));
@ -669,6 +669,29 @@ public class FailableFunctionsTest {
assertEquals(0, biFunction.apply(testable, null).intValue());
}
@Test
public void testBiFunctionAndThen() throws IOException {
// Unchecked usage pattern in JRE
final BiFunction<Object, Integer, Integer> nopBiFunction = (t, u) -> null;
final Function<Object, Integer> nopFunction = (t) -> null;
nopBiFunction.andThen(nopFunction);
// Checked usage pattern
final FailableBiFunction<Object, Integer, Integer, IOException> failingBiFunctionTest = (t, u) -> {
throw new IOException();
};
final FailableFunction<Object, Integer, IOException> failingFunction = (t) -> { throw new IOException(); };
final FailableBiFunction<Object, Integer, Integer, IOException> nopFailableBiFunction = FailableBiFunction.nop();
final FailableFunction<Object, Integer, IOException> nopFailableFunction = FailableFunction.nop();
//
assertThrows(IOException.class, () -> failingBiFunctionTest.andThen(failingFunction).apply(null, null));
assertThrows(IOException.class, () -> failingBiFunctionTest.andThen(nopFailableFunction).apply(null, null));
//
assertThrows(IOException.class, () -> nopFailableBiFunction.andThen(failingFunction).apply(null, null));
nopFailableBiFunction.andThen(nopFailableFunction).apply(null, null);
// Documented in Javadoc edge-case.
assertThrows(NullPointerException.class, () -> failingBiFunctionTest.andThen(null));
}
@Test
@DisplayName("Test that asPredicate(FailableBiPredicate) is converted to -> BiPredicate ")
public void testBiPredicate() {