eaglercraft-1.8/sources/main/java/com/google/common/base/Function.java
2022-12-25 01:12:28 -08:00

75 lines
2.5 KiB
Java

/*
* Copyright (C) 2007 The Guava 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
*
* 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 com.google.common.base;
import javax.annotation.Nullable;
import com.google.common.annotations.GwtCompatible;
/**
* Determines an output value based on an input value.
*
* <p>
* The {@link Functions} class provides common functions and related utilites.
*
* <p>
* See the Guava User Guide article on <a href=
* "http://code.google.com/p/guava-libraries/wiki/FunctionalExplained">the use
* of {@code
* Function}</a>.
*
* @author Kevin Bourrillion
* @since 2.0 (imported from Google Collections Library)
*/
@GwtCompatible
public interface Function<F, T> {
/**
* Returns the result of applying this function to {@code input}. This method is
* <i>generally expected</i>, but not absolutely required, to have the following
* properties:
*
* <ul>
* <li>Its execution does not cause any observable side effects.
* <li>The computation is <i>consistent with equals</i>; that is,
* {@link Objects#equal Objects.equal}{@code (a, b)} implies that
* {@code Objects.equal(function.apply(a),
* function.apply(b))}.
* </ul>
*
* @throws NullPointerException if {@code input} is null and this function does
* not accept null arguments
*/
@Nullable
T apply(@Nullable F input);
/**
* Indicates whether another object is equal to this function.
*
* <p>
* Most implementations will have no reason to override the behavior of
* {@link Object#equals}. However, an implementation may also choose to return
* {@code true} whenever {@code object} is a {@link Function} that it considers
* <i>interchangeable</i> with this one. "Interchangeable" <i>typically</i>
* means that {@code Objects.equal(this.apply(f), that.apply(f))} is true for
* all {@code f} of type {@code F}. Note that a {@code false} result from this
* method does not imply that the functions are known <i>not</i> to be
* interchangeable.
*/
@Override
boolean equals(@Nullable Object object);
}