package jdk.internal.misc;

import java.util.Arrays;
import java.util.function.Consumer;

public class JdkThreadLocal<T> extends ThreadLocal<T> {
    protected void threadTerminated(T value) {
    }

    public void callThreadTerminated(Object value) {
        @SuppressWarnings("unchecked")
        final T v = (T) value;
        threadTerminated(v);
    }

    public JdkThreadLocal() {
        add(this);
    }

    private static final class Entry<U> {
        private final JdkThreadLocal<U> threadLocal;

        private Entry(JdkThreadLocal<U> threadLocal) {
            this.threadLocal = threadLocal;
        }

        public JdkThreadLocal<U> threadLocal() {
            return threadLocal;
        }
    }

    private static volatile Entry<?>[] entries = new Entry<?>[0];

    private static synchronized <U> void add(JdkThreadLocal<U> threadLocal) {
        if (threadLocal == null) {
            throw new IllegalArgumentException("threadLocal is null");
        }
        forEach(tl -> {
            if (tl == threadLocal) {
                throw new IllegalArgumentException("threadLocal has already been added");
            }
        });

        final Entry<U> entry = new Entry<>(threadLocal);
        final Entry<?>[] entries0 = Arrays.copyOf(entries, entries.length + 1);
        entries0[entries0.length - 1] = entry;
        entries = entries0;
    }

    public static void forEach(Consumer<JdkThreadLocal<?>> f) {
        final Entry<?>[] entries0 = entries;
        for (Entry<?> e: entries0) {
            final JdkThreadLocal<?> tl = e.threadLocal();
            f.accept(tl);
        }
    }
}