co.easimart.LockSet Maven / Gradle / Ivy

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package co.easimart;

import java.util.Collection;
import java.util.Comparator;
import java.util.Set;
import java.util.TreeSet;
import java.util.WeakHashMap;
import java.util.concurrent.locks.Lock;

/** package */ class LockSet {
  private static WeakHashMap stableIds = new WeakHashMap();
  private static long nextStableId = 0L;

  private final Set locks;

  public LockSet(Collection locks) {
    this.locks = new TreeSet(new Comparator() {
      @Override
      public int compare(Lock lhs, Lock rhs) {
        Long lhsId = getStableId(lhs);
        Long rhsId = getStableId(rhs);
        return lhsId.compareTo(rhsId);
      }
    });
    this.locks.addAll(locks);
  }

  private static Long getStableId(Lock lock) {
    synchronized (stableIds) {
      if (stableIds.containsKey(lock)) {
        return stableIds.get(lock);
      }
      long id = nextStableId++;
      stableIds.put(lock, id);
      return id;
    }
  }

  public void lock() {
    for (Lock l : locks) {
      l.lock();
    }
  }

  public void unlock() {
    for (Lock l : locks) {
      l.unlock();
    }
  }
}