// Copyright 2014 The Bazel Authors. All rights reserved. // // 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.devtools.build.lib.skyframe; import com.google.common.base.MoreObjects; import com.google.common.base.Supplier; /** * Supplier whose value can be changed by clients who have a reference to it as a MutableSupplier. * Unlike an {@code AtomicReference}, clients who are passed a MutableSupplier as a Supplier cannot * change its value without a reckless cast. */ public class MutableSupplier<T> implements Supplier<T> { private T val; @Override public T get() { return val; } /** * Sets the value of the object supplied. Do not cast a Supplier to a MutableSupplier in order to * call this method! */ public void set(T newVal) { val = newVal; } @Override public String toString() { return MoreObjects.toStringHelper(getClass()) .add("val", val).toString(); } }