private static void prepare(boolean quitAllowed) { 
  if (sThreadLocal.get() != null) { 
    throw new RuntimeException("Only one Looper may be created per thread"); 
  } 
  sThreadLocal.set(new Looper(quitAllowed)); 
} 

public void set(T value) { 
  Thread currentThread = Thread.currentThread(); 
  Values values = values(currentThread); 
  if (values == null) { 
    values = initializeValues(currentThread); 
  } 
  values.put(this, value); 
} 

/** 
 * Gets Values instance for this thread and variable type. 
 */ 
Values values(Thread current) { 
  return current.localValues; 
} 

/** 
  * Normal thread local values. 
  */ 
  ThreadLocal.Values localValues; 

/** 
 * Sets entry for given ThreadLocal to given value, creating an 
 * entry if necessary. 
 */ 
void put(ThreadLocal<?> key, Object value) { 
  cleanUp(); 
 
  // Keep track of first tombstone. That's where we want to go back 
  // and add an entry if necessary. 
  int firstTombstone = -1; 
 
  for (int index = key.hash & mask;; index = next(index)) { 
    Object k = table[index]; 
 
    if (k == key.reference) { 
      // Replace existing entry. 
      table[index + 1] = value; 
      return; 
    } 
 
    if (k == null) { 
      if (firstTombstone == -1) { 
        // Fill in null slot. 
        table[index] = key.reference; 
        table[index + 1] = value; 
        size++; 
        return; 
      } 
 
      // Go back and replace first tombstone. 
      table[firstTombstone] = key.reference; 
      table[firstTombstone + 1] = value; 
      tombstones--; 
      size++; 
      return; 
    } 
 
    // Remember first tombstone. 
    if (firstTombstone == -1 && k == TOMBSTONE) { 
      firstTombstone = index; 
    } 
  } 
} 

public T get() { 
    // Optimized for the fast path. 
    Thread currentThread = Thread.currentThread(); 
    Values values = values(currentThread); 
    if (values != null) { 
      Object[] table = values.table; 
      int index = hash & values.mask; 
      if (this.reference == table[index]) { 
        return (T) table[index + 1]; 
      } 
    } else { 
      values = initializeValues(currentThread); 
    } 
 
    return (T) values.getAfterMiss(this); 
  }