Add Throwable functional interfaces

Add 'Throwable' variants of the `Consumer`, `Function`, `BiFunction` and
`Supplier` interfaces that wrap checked exceptions or allow calls to be
made that throw them.

Closes gh-28417

spring-core/src/test/java/org/springframework/util/function/ThrowingBiFunctionTests.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.util.function;
+
+import java.io.IOException;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+
+/**
+ * Tests for {@link ThrowingBiFunction}.
+ *
+ * @author Phillip Webb
+ * @since 6.0
+ */
+class ThrowingBiFunctionTests {
+
+	@Test
+	void applyWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingBiFunction<Object, Object, Object> function = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(() -> function.apply(this, this));
+	}
+
+	@Test
+	void applyWhenThrowingCheckedExceptionThrowsWrapperRuntimeException() {
+		ThrowingBiFunction<Object, Object, Object> function = this::throwIOException;
+		assertThatExceptionOfType(RuntimeException.class).isThrownBy(
+				() -> function.apply(this, this)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void applyWithExceptionWrapperWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingBiFunction<Object, Object, Object> function = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(
+				() -> function.apply(this, this, IllegalStateException::new));
+	}
+
+	@Test
+	void applyWithExceptionWrapperWhenThrowingCheckedExceptionThrowsWrapper() {
+		ThrowingBiFunction<Object, Object, Object> function = this::throwIOException;
+		assertThatIllegalStateException().isThrownBy(() -> function.apply(this, this,
+				IllegalStateException::new)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void throwingModifiesThrownException() {
+		ThrowingBiFunction<Object, Object, Object> function = this::throwIOException;
+		ThrowingBiFunction<Object, Object, Object> modified = function.throwing(
+				IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> modified.apply(this, this)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void ofModifiesThrowException() {
+		ThrowingBiFunction<Object, Object, Object> function = ThrowingBiFunction.of(
+				this::throwIOException, IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> function.apply(this, this)).withCauseInstanceOf(IOException.class);
+	}
+
+	private Object throwIOException(Object o, Object u) throws IOException {
+		throw new IOException();
+	}
+
+	private Object throwIllegalArgumentException(Object o, Object u) throws IOException {
+		throw new IllegalArgumentException();
+	}
+
+}

spring-core/src/test/java/org/springframework/util/function/ThrowingConsumerTests.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.util.function;
+
+import java.io.IOException;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+
+/**
+ * Tests for {@link ThrowingConsumer}.
+ *
+ * @author Phillip Webb
+ * @since 6.0
+ */
+class ThrowingConsumerTests {
+
+	@Test
+	void applyWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingConsumer<Object> consumer = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(() -> consumer.accept(this));
+	}
+
+	@Test
+	void applyWhenThrowingCheckedExceptionThrowsWrapperRuntimeException() {
+		ThrowingConsumer<Object> consumer = this::throwIOException;
+		assertThatExceptionOfType(RuntimeException.class).isThrownBy(
+				() -> consumer.accept(this)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void applyWithExceptionWrapperWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingConsumer<Object> consumer = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(
+				() -> consumer.accept(this, IllegalStateException::new));
+	}
+
+	@Test
+	void applyWithExceptionWrapperWhenThrowingCheckedExceptionThrowsWrapper() {
+		ThrowingConsumer<Object> consumer = this::throwIOException;
+		assertThatIllegalStateException().isThrownBy(() -> consumer.accept(this,
+				IllegalStateException::new)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void throwingModifiesThrownException() {
+		ThrowingConsumer<Object> consumer = this::throwIOException;
+		ThrowingConsumer<Object> modified = consumer.throwing(
+				IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> modified.accept(this)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void ofModifiesThrowException() {
+		ThrowingConsumer<Object> consumer = ThrowingConsumer.of(this::throwIOException,
+				IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> consumer.accept(this)).withCauseInstanceOf(IOException.class);
+	}
+
+	private void throwIOException(Object o) throws IOException {
+		throw new IOException();
+	}
+
+	private void throwIllegalArgumentException(Object o) throws IOException {
+		throw new IllegalArgumentException();
+	}
+
+}

spring-core/src/test/java/org/springframework/util/function/ThrowingFunctionTests.java

@@ -0,0 +1,87 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.util.function;
+
+import java.io.IOException;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+
+/**
+ * Tests for {@link ThrowingFunction}.
+ *
+ * @author Phillip Webb
+ * @since 6.0
+ */
+class ThrowingFunctionTests {
+
+	@Test
+	void applyWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingFunction<Object, Object> function = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(() -> function.apply(this));
+	}
+
+	@Test
+	void applyWhenThrowingCheckedExceptionThrowsWrapperRuntimeException() {
+		ThrowingFunction<Object, Object> function = this::throwIOException;
+		assertThatExceptionOfType(RuntimeException.class).isThrownBy(
+				() -> function.apply(this)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void applyWithExceptionWrapperWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingFunction<Object, Object> function = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(
+				() -> function.apply(this, IllegalStateException::new));
+	}
+
+	@Test
+	void applyWithExceptionWrapperWhenThrowingCheckedExceptionThrowsWrapper() {
+		ThrowingFunction<Object, Object> function = this::throwIOException;
+		assertThatIllegalStateException().isThrownBy(() -> function.apply(this,
+				IllegalStateException::new)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void throwingModifiesThrownException() {
+		ThrowingFunction<Object, Object> function = this::throwIOException;
+		ThrowingFunction<Object, Object> modified = function.throwing(
+				IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> modified.apply(this)).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void ofModifiesThrowException() {
+		ThrowingFunction<Object, Object> function = ThrowingFunction.of(
+				this::throwIOException, IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> function.apply(this)).withCauseInstanceOf(IOException.class);
+	}
+
+	private Object throwIOException(Object o) throws IOException {
+		throw new IOException();
+	}
+
+	private Object throwIllegalArgumentException(Object o) throws IOException {
+		throw new IllegalArgumentException();
+	}
+
+}

spring-core/src/test/java/org/springframework/util/function/ThrowingSupplierTests.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright 2002-2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.util.function;
+
+import java.io.IOException;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+
+/**
+ * Tests for {@link ThrowingSupplier}.
+ *
+ * @author Phillip Webb
+ * @since 6.0
+ */
+class ThrowingSupplierTests {
+
+	@Test
+	void getWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingSupplier<Object> supplier = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(supplier::get);
+	}
+
+	@Test
+	void getWhenThrowingCheckedExceptionThrowsWrapperRuntimeException() {
+		ThrowingSupplier<Object> supplier = this::throwIOException;
+		assertThatExceptionOfType(RuntimeException.class).isThrownBy(
+				supplier::get).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void getWithExceptionWrapperWhenThrowingUncheckedExceptionThrowsOriginal() {
+		ThrowingSupplier<Object> supplier = this::throwIllegalArgumentException;
+		assertThatIllegalArgumentException().isThrownBy(
+				() -> supplier.get(IllegalStateException::new));
+	}
+
+	@Test
+	void getWithExceptionWrapperWhenThrowingCheckedExceptionThrowsWrapper() {
+		ThrowingSupplier<Object> supplier = this::throwIOException;
+		assertThatIllegalStateException().isThrownBy(
+				() -> supplier.get(IllegalStateException::new)).withCauseInstanceOf(
+						IOException.class);
+	}
+
+	@Test
+	void throwingModifiesThrownException() {
+		ThrowingSupplier<Object> supplier = this::throwIOException;
+		ThrowingSupplier<Object> modified = supplier.throwing(
+				IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> modified.get()).withCauseInstanceOf(IOException.class);
+	}
+
+	@Test
+	void ofModifiesThrowException() {
+		ThrowingSupplier<Object> supplier = ThrowingSupplier.of(
+				this::throwIOException, IllegalStateException::new);
+		assertThatIllegalStateException().isThrownBy(
+				() -> supplier.get()).withCauseInstanceOf(IOException.class);
+	}
+
+	private Object throwIOException() throws IOException {
+		throw new IOException();
+	}
+
+	private Object throwIllegalArgumentException() throws IOException {
+		throw new IllegalArgumentException();
+	}
+
+}