| /* |
| * 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 com.google.common.annotations.GwtCompatible; |
| import com.google.errorprone.annotations.CanIgnoreReturnValue; |
| import org.checkerframework.checker.nullness.qual.Nullable; |
| |
| /** |
| * Legacy version of {@link java.util.function.Function java.util.function.Function}. |
| * |
| * <p>The {@link Functions} class provides common functions and related utilities. |
| * |
| * <p>As this interface extends {@code java.util.function.Function}, an instance of this type can be |
| * used as a {@code java.util.function.Function} directly. To use a {@code |
| * java.util.function.Function} in a context where a {@code com.google.common.base.Function} is |
| * needed, use {@code function::apply}. |
| * |
| * <p>This interface is now a legacy type. Use {@code java.util.function.Function} (or the |
| * appropriate primitive specialization such as {@code ToIntFunction}) instead whenever possible. |
| * Otherwise, at least reduce <i>explicit</i> dependencies on this type by using lambda expressions |
| * or method references instead of classes, leaving your code easier to migrate in the future. |
| * |
| * <p>See the Guava User Guide article on <a |
| * href="https://github.com/google/guava/wiki/FunctionalExplained">the use of {@code Function}</a>. |
| * |
| * @author Kevin Bourrillion |
| * @since 2.0 |
| */ |
| @GwtCompatible |
| @FunctionalInterface |
| public interface Function<F, T> extends java.util.function.Function<F, T> { |
| @Override |
| @CanIgnoreReturnValue // TODO(kevinb): remove this |
| @Nullable |
| T apply(@Nullable F input); |
| |
| /** |
| * <i>May</i> return {@code true} if {@code object} is a {@code Function} that behaves identically |
| * to this function. |
| * |
| * <p><b>Warning: do not depend</b> on the behavior of this method. |
| * |
| * <p>Historically, {@code Function} instances in this library have implemented this method to |
| * recognize certain cases where distinct {@code Function} instances would in fact behave |
| * identically. However, as code migrates to {@code java.util.function}, that behavior will |
| * disappear. It is best not to depend on it. |
| */ |
| @Override |
| boolean equals(@Nullable Object object); |
| } |