android/guava/src/com/google/common/util/concurrent/Monitor.java
public boolean enterIf(Guard guard) {
    if (guard.monitor != this) {
      throw new IllegalMonitorStateException();
    }
    final ReentrantLock lock = this.lock;
    lock.lock();

    boolean satisfied = false;
    try {
      return satisfied = guard.isSatisfied();
    } finally {
      if (!satisfied) {
        lock.unlock();
      }
    }
  }
public boolean enterIf(Guard guard) {
    if (guard.monitor != this) {
      throw new IllegalMonitorStateException();
    }
    final ReentrantLock lock = this.lock;
    lock.lock();

    boolean satisfied = false;
    try {
      return satisfied = guard.isSatisfied();
    } finally {
      if (!satisfied) {
        lock.unlock();
      }
    }
  }
public boolean enterIf ( Guard guard ) { if ( guard . monitor != this ) { throw new IllegalMonitorStateException ( ) ; } final ReentrantLock lock = this . lock ; lock . lock ( ) ; boolean satisfied = false ; try { return satisfied = guard . isSatisfied ( ) ; } finally { if ( ! satisfied ) { lock . unlock ( ) ; } } }
Enters this monitor if the guard is satisfied. Blocks indefinitely acquiring the lock, but does
not wait for the guard to be satisfied.

@return whether the monitor was entered, which guarantees that the guard is now satisfied
Enters this monitor if the guard is satisfied . Blocks indefinitely acquiring the lock but does not wait for the guard to be satisfied .