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Add Throwable functional interfaces
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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
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philwebb committed May 5, 2022
1 parent d30e6bf commit b3efdf3
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/*
* 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.util.function.BiFunction;

/**
* A {@link BiFunction} that allows invocation of code that throws a checked
* exception.
*
* @author Stephane Nicoll
* @author Phillip Webb
* @since 6.0
* @param <T> the type of the first argument to the function
* @param <U> the type of the second argument to the function
* @param <R> the type of the result of the function
*/
public interface ThrowingBiFunction<T, U, R> extends BiFunction<T, U, R> {

/**
* Applies this function to the given argument, possibly throwing a checked
* exception.
* @param t the first function argument
* @param u the second function argument
* @return the function result
* @throws Exception on error
*/
R applyWithException(T t, U u) throws Exception;

/**
* Default {@link BiFunction#apply(Object, Object)} that wraps any thrown
* checked exceptions (by default in a {@link RuntimeException}).
* @param t the first function argument
* @param u the second function argument
* @return the function result
* @see java.util.function.BiFunction#apply(Object, Object)
*/
@Override
default R apply(T t, U u) {
return apply(t, u, RuntimeException::new);
}

/**
* Applies this function to the given argument, wrapping any thrown checked
* exceptions using the given {@code exceptionWrapper}.
* @param t the first function argument
* @param u the second function argument
* @param exceptionWrapper {@link BiFunction} that wraps the given message
* and checked exception into a runtime exception
* @return a result
*/
default R apply(T t, U u, BiFunction<String, Exception, RuntimeException> exceptionWrapper) {
try {
return applyWithException(t, u);
}
catch (RuntimeException ex) {
throw ex;
}
catch (Exception ex) {
throw exceptionWrapper.apply(ex.getMessage(), ex);
}
}

/**
* Return a new {@link ThrowingBiFunction} where the
* {@link #apply(Object, Object)} method wraps any thrown checked exceptions
* using the given {@code exceptionWrapper}.
* @param exceptionWrapper {@link BiFunction} that wraps the given message
* and checked exception into a runtime exception
* @return the replacement {@link ThrowingBiFunction} instance
*/
default ThrowingBiFunction<T, U, R> throwing(BiFunction<String, Exception, RuntimeException> exceptionWrapper) {
return new ThrowingBiFunction<>() {

@Override
public R applyWithException(T t, U u) throws Exception {
return ThrowingBiFunction.this.applyWithException(t, u);
}

@Override
public R apply(T t, U u) {
return apply(t, u, exceptionWrapper);
}

};
}

/**
* Lambda friendly convenience method that can be used to create
* {@link ThrowingBiFunction} where the {@link #apply(Object, Object)}
* method wraps any thrown checked exceptions using the given
* {@code exceptionWrapper}.
* @param <T> the type of the first argument to the function
* @param <U> the type of the second argument to the function
* @param <R> the type of the result of the function
* @param function the source function
* @return a new {@link ThrowingFunction} instance
*/
static <T, U, R> ThrowingBiFunction<T, U, R> of(ThrowingBiFunction<T, U, R> function) {
return function;
}

/**
* Lambda friendly convenience method that can be used to create
* {@link ThrowingBiFunction} where the {@link #apply(Object, Object)}
* method wraps any thrown checked exceptions using the given
* {@code exceptionWrapper}.
* @param <T> the type of the first argument to the function
* @param <U> the type of the second argument to the function
* @param <R> the type of the result of the function
* @param function the source function
* @param exceptionWrapper the exception wrapper to use
* @return a new {@link ThrowingFunction} instance
*/
static <T, U, R> ThrowingBiFunction<T, U, R> of(ThrowingBiFunction<T, U, R> function,
BiFunction<String, Exception, RuntimeException> exceptionWrapper) {

return function.throwing(exceptionWrapper);
}

}
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/*
* 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.util.function.BiFunction;
import java.util.function.Consumer;

/**
* A {@link Consumer} that allows invocation of code that throws a checked
* exception.
*
* @author Stephane Nicoll
* @author Phillip Webb
* @since 6.0
* @param <T> the type of the input to the operation
*/
@FunctionalInterface
public interface ThrowingConsumer<T> extends Consumer<T> {

/**
* Performs this operation on the given argument, possibly throwing a
* checked exception.
* @param t the input argument
* @throws Exception on error
*/
void acceptWithException(T t) throws Exception;

/**
* Default {@link Consumer#accept(Object)} that wraps any thrown checked
* exceptions (by default in a {@link RuntimeException}).
* @see java.util.function.Consumer#accept(Object)
*/
@Override
default void accept(T t) {
accept(t, RuntimeException::new);
}

/**
* Performs this operation on the given argument, wrapping any thrown
* checked exceptions using the given {@code exceptionWrapper}.
* @param exceptionWrapper {@link BiFunction} that wraps the given message
* and checked exception into a runtime exception
*/
default void accept(T t,BiFunction<String, Exception, RuntimeException> exceptionWrapper) {
try {
acceptWithException(t);
}
catch (RuntimeException ex) {
throw ex;
}
catch (Exception ex) {
throw exceptionWrapper.apply(ex.getMessage(), ex);
}
}

/**
* Return a new {@link ThrowingConsumer} where the {@link #accept(Object)}
* method wraps any thrown checked exceptions using the given
* {@code exceptionWrapper}.
* @param exceptionWrapper {@link BiFunction} that wraps the given message
* and checked exception into a runtime exception
* @return the replacement {@link ThrowingConsumer} instance
*/
default ThrowingConsumer<T> throwing(BiFunction<String, Exception, RuntimeException> exceptionWrapper) {
return new ThrowingConsumer<>() {

@Override
public void acceptWithException(T t) throws Exception {
ThrowingConsumer.this.acceptWithException(t);
}

@Override
public void accept(T t) {
accept(t, exceptionWrapper);
}

};
}

/**
* Lambda friendly convenience method that can be used to create
* {@link ThrowingConsumer} where the {@link #accept(Object)} method wraps
* any thrown checked exceptions using the given {@code exceptionWrapper}.
* @param <T> the type of the input to the operation
* @param consumer the source consumer
* @return a new {@link ThrowingConsumer} instance
*/
static <T> ThrowingConsumer<T> of(ThrowingConsumer<T> consumer) {
return consumer;
}

/**
* Lambda friendly convenience method that can be used to create
* {@link ThrowingConsumer} where the {@link #accept(Object)} method wraps
* any thrown checked exceptions using the given {@code exceptionWrapper}.
* @param <T> the type of the input to the operation
* @param consumer the source consumer
* @param exceptionWrapper the exception wrapper to use
* @return a new {@link ThrowingConsumer} instance
*/
static <T> ThrowingConsumer<T> of(ThrowingConsumer<T> consumer,
BiFunction<String, Exception, RuntimeException> exceptionWrapper) {

return consumer.throwing(exceptionWrapper);
}

}
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/*
* 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.util.function.BiFunction;
import java.util.function.Function;

/**
* A {@link Function} that allows invocation of code that throws a checked
* exception.
*
* @author Stephane Nicoll
* @author Phillip Webb
* @since 6.0
* @param <T> the type of the input to the function
* @param <R> the type of the result of the function
*/
@FunctionalInterface
public interface ThrowingFunction<T, R> extends Function<T, R> {

/**
* Applies this function to the given argument, possibly throwing a checked
* exception.
* @param t the function argument
* @return the function result
* @throws Exception on error
*/
R applyWithException(T t) throws Exception;

/**
* Default {@link Function#apply(Object)} that wraps any thrown checked
* exceptions (by default in a {@link RuntimeException}).
* @see java.util.function.Function#apply(java.lang.Object)
*/
@Override
default R apply(T t) {
return apply(t, RuntimeException::new);
}

/**
* Applies this function to the given argument, wrapping any thrown checked
* exceptions using the given {@code exceptionWrapper}.
* @param exceptionWrapper {@link BiFunction} that wraps the given message
* and checked exception into a runtime exception
* @return a result
*/
default R apply(T t, BiFunction<String, Exception, RuntimeException> exceptionWrapper) {
try {
return applyWithException(t);
}
catch (RuntimeException ex) {
throw ex;
}
catch (Exception ex) {
throw exceptionWrapper.apply(ex.getMessage(), ex);
}
}

/**
* Return a new {@link ThrowingFunction} where the {@link #apply(Object)}
* method wraps any thrown checked exceptions using the given
* {@code exceptionWrapper}.
* @param exceptionWrapper {@link BiFunction} that wraps the given message
* and checked exception into a runtime exception
* @return the replacement {@link ThrowingFunction} instance
*/
default ThrowingFunction<T, R> throwing(BiFunction<String, Exception, RuntimeException> exceptionWrapper) {
return new ThrowingFunction<>() {

@Override
public R applyWithException(T t) throws Exception {
return ThrowingFunction.this.applyWithException(t);
}

@Override
public R apply(T t) {
return apply(t, exceptionWrapper);
}

};
}

/**
* Lambda friendly convenience method that can be used to create
* {@link ThrowingFunction} where the {@link #apply(Object)} method wraps
* any thrown checked exceptions using the given {@code exceptionWrapper}.
* @param <T> the type of the input to the function
* @param <R> the type of the result of the function
* @param function the source function
* @return a new {@link ThrowingFunction} instance
*/
static <T, R> ThrowingFunction<T, R> of(ThrowingFunction<T, R> function) {
return function;
}

/**
* Lambda friendly convenience method that can be used to create
* {@link ThrowingFunction} where the {@link #apply(Object)} method wraps
* any thrown checked exceptions using the given {@code exceptionWrapper}.
* @param <T> the type of the input to the function
* @param <R> the type of the result of the function
* @param function the source function
* @param exceptionWrapper the exception wrapper to use
* @return a new {@link ThrowingFunction} instance
*/
static <T, R> ThrowingFunction<T, R> of(ThrowingFunction<T, R> function,
BiFunction<String, Exception, RuntimeException> exceptionWrapper) {

return function.throwing(exceptionWrapper);
}

}
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