netty-incubator-buffer-api/src/test/java/io/netty/buffer/api/Memoize.java

37 lines
1.0 KiB
Java

/*
* Copyright 2021 The Netty Project
*
* The Netty Project 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:
*
* https://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 io.netty.buffer.api;
import java.util.function.Supplier;
final class Memoize<T> implements Supplier<T> {
private final Supplier<T> supplier;
private volatile T memo;
Memoize(Supplier<T> supplier) {
this.supplier = supplier;
}
@Override
public T get() {
T val = memo;
if (val == null) {
memo = val = supplier.get();
}
return val;
}
}