org.jetbrains.kotlin.storage.SingleThreadValue Maven / Gradle / Ivy
/*
* Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
package org.jetbrains.kotlin.storage;
/**
* A storage for the value that should exist and be accessible in the single thread.
*
* Unlike ThreadLocal, thread doesn't store a reference to the value that makes it inaccessible globally, but simplifies memory
* management.
*
* The other difference from ThreadLocal is inability to have different values per each thread, so SingleThreadValue instance
* should be protected with external lock from rewrites.
*
* @param
*/
class SingleThreadValue {
private final T value;
private final Thread thread;
SingleThreadValue(T value) {
this.value = value;
thread = Thread.currentThread();
}
public boolean hasValue() {
return thread == Thread.currentThread();
}
public T getValue() {
if (!hasValue()) throw new IllegalStateException("No value in this thread (hasValue should be checked before)");
return value;
}
}