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Miscellaneous Utilities (Pure Java)
/*
* Copyright (c) 2018 by Andrew Charneski.
*
* The author 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
*
* 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.simiacryptus.util.function;
import java.util.function.Supplier;
/**
* The type Cached supplier.
*
* @param the type parameter
*/
public class CachedSupplier implements Supplier {
private final Supplier fn;
private volatile T cached;
/**
* Instantiates a new Cached supplier.
*
* @param fn the fn
*/
public CachedSupplier(Supplier fn) {
this.fn = fn;
}
@Override
public T get() {
T obj = cached;
if (null == obj) {
synchronized (this) {
obj = cached;
if (null == obj) {
obj = fn.get();
cached = (obj);
}
}
}
return obj;
}
}