| /* |
| * 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; |
| |
| /** |
| * A class that can supply objects of a single type; a pre-Java-8 version of {@link |
| * java.util.function.Supplier java.util.function.Supplier}. Semantically, this could be a factory, |
| * generator, builder, closure, or something else entirely. No guarantees are implied by this |
| * interface. |
| * |
| * <p>The {@link Suppliers} class provides common suppliers and related utilities. |
| * |
| * <p>See the Guava User Guide article on <a href= |
| * "https://github.com/google/guava/wiki/FunctionalExplained">the use of functional types</a>. |
| * |
| * <h3>For Java 8+ users</h3> |
| * |
| * <p>This interface is now a legacy type. Use {@code java.util.function.Supplier} (or the |
| * appropriate primitive specialization such as {@code IntSupplier}) 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>To use an existing supplier instance (say, named {@code supplier}) in a context where the |
| * <i>other type</i> of supplier is expected, use the method reference {@code supplier::get}. A |
| * future version of {@code com.google.common.base.Supplier} will be made to <i>extend</i> {@code |
| * java.util.function.Supplier}, making conversion code necessary only in one direction. At that |
| * time, this interface will be officially discouraged. |
| * |
| * @author Harry Heymann |
| * @since 2.0 |
| */ |
| @GwtCompatible |
| public interface Supplier<T> { |
| /** |
| * Retrieves an instance of the appropriate type. The returned object may or may not be a new |
| * instance, depending on the implementation. |
| * |
| * @return an instance of the appropriate type |
| */ |
| @CanIgnoreReturnValue |
| T get(); |
| } |