org.apache.sshd.common.util.io.functors.IOFunction Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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
*
* http://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.apache.sshd.common.util.io.functors;
import java.io.IOException;
import java.util.Objects;
/**
* Invokes some I/O function on the input returning some output and potentially throwing an {@link IOException} in the
* process
*
* @param Type of input
* @param Type of output
* @author Apache MINA SSHD Project
*/
@FunctionalInterface
public interface IOFunction {
R apply(T t) throws IOException;
/**
* Returns a composed function that first applies the {@code before} function to its input, and then applies this
* function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the
* composed function.
*
* @param the type of input to the {@code before} function, and to the composed function
* @param before the function to apply before this function is applied
* @return a composed function that first applies the {@code before} function and then applies
* this function
* @throws NullPointerException if before is null
*
* @see #andThen(IOFunction)
*/
default IOFunction compose(IOFunction before) {
Objects.requireNonNull(before, "No composing function provided");
return (V v) -> apply(before.apply(v));
}
/**
* Returns a composed function that first applies this function to its input, and then applies the {@code after}
* function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the
* composed function.
*
* @param the type of output of the {@code after} function, and of the composed function
* @param after the function to apply after this function is applied
* @return a composed function that first applies this function and then applies the
* {@code after} function
* @throws NullPointerException if after is null
*
* @see #compose(IOFunction)
*/
default IOFunction andThen(IOFunction after) {
Objects.requireNonNull(after, "No composing function provided");
return (T t) -> after.apply(apply(t));
}
/**
* Returns a function that always returns its input argument.
*
* @param the type of the input and output objects to the function
* @return a function that always returns its input argument
*/
static IOFunction identity() {
return t -> t;
}
}