| /* |
| * Copyright 2000-2009 JetBrains s.r.o. |
| * |
| * 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.intellij.util; |
| |
| import org.jetbrains.annotations.Nullable; |
| |
| public abstract class VolatileDoubleCheckedLockedInit<T> { |
| private volatile boolean myInitialized; |
| private T myInstance; |
| private final Object myLock; |
| |
| public VolatileDoubleCheckedLockedInit() { |
| myLock = new Object(); |
| } |
| |
| @Nullable |
| protected abstract T createT(); |
| |
| @Nullable |
| public T get() { |
| if (! myInitialized) { |
| synchronized (myLock) { |
| if (! myInitialized) { |
| myInstance = createT(); |
| myInitialized = true; |
| } |
| } |
| } |
| return myInstance; |
| } |
| |
| public void reset() { |
| myInitialized = false; |
| } |
| } |