package net.avcompris.commons3.dao.impl;
   
   import static com.google.common.base.Preconditions.checkNotNull;
   
   import java.io.IOException;
   import java.sql.SQLException;
   
   import org.apache.commons.logging.Log;
   import org.apache.commons.logging.LogFactory;
  
  import net.avcompris.commons3.utils.Clock;
  
  public abstract class AbstractDao {
  
  	private static final Log logger = LogFactory.getLog(AbstractDao.class);
  
  	protected final Clock clock;
  
  	protected AbstractDao(final Clock clock) {
  
  		this.clock = checkNotNull(clock, "clock");
  	}
  
  	@FunctionalInterface
  	protected interface Action<T> {
  
  		T action() throws SQLException, IOException;
  	}
  
  	protected static final <T> T retryUntil(final long timeoutMs, final long delayMs, final Action<T> action)
  			throws SQLException, IOException {
  
  		return retryUntil(timeoutMs, delayMs, true, action);
  	}
  
  	protected static final <T> T retryUntil(final long timeoutMs, final long delayMs,
  			final boolean throwExceptionInCaseOfTimeout, final Action<T> action) throws SQLException, IOException {
  
  		checkNotNull(action, "action");
  
  		for (final long startMs = System.currentTimeMillis(); System.currentTimeMillis() < startMs + timeoutMs;) {
  
  			T result = null;
  
  			try {
  
  				result = action.action();
  
  			} catch (final SQLException | IOException | RuntimeException | Error e) {
  
  				throw e;
  
  			} catch (final Exception e) {
  
  				throw new RuntimeException(e);
  			}
  
  			if (result != null) {
  
  				return result;
  			}
  
  			try {
  
  				Thread.sleep(delayMs);
  
  			} catch (final InterruptedException e) {
  
  				e.printStackTrace();
  
  				// do nothing
  			}
  		}
  
  		logger.error("A timeout occurs (" + timeoutMs + " ms)");
  
  		if (throwExceptionInCaseOfTimeout) {
  
  			throw new RuntimeException("Timeout after: " + timeoutMs + " ms");
  
  		} else {
  
  			return null;
  		}
  	}
  }