package cz.cuni.amis.utils.flag;
   
   import java.io.Serializable;
   
   /**
    * This class is cruicial in order to have synchronized increments on the integer flag.
    * <p><p>
    * The .setFlag() mechanism is very complex and it is sometimes not viable to do .setFlag() call
    * inside synchronized statements (deadlocks!) therefore we have to solve it inside the class.
   * 
   * @author Jimmy
   *
   */
  public class FlagInteger extends Flag<Integer> implements Serializable {
  	
  	/**
  	 * This class extends the DoInSync of the reason that was passed along.
  	 */
  	public static abstract class DoInSyncWithReason<T, R> extends DoInSync<T> {
  		
  		/**
  		 * Tells you whether you operate over immutable flag (can't call setFlag() then) or not.
  		 * @return
  		 */
  		protected boolean isImmutable() {
  			return flag instanceof ImmutableFlag;
  		}
  		
  		/**
  		 * Set value in sync.
  		 */
  		protected void setFlag(T value, R reason) {
  			if (flag instanceof ImmutableFlag) throw new UnsupportedOperationException("trying to set flag of the immutable flag!");
  			flag.value = value;
  			flag.notifier.setValue(value);
  			flag.listeners.notify(flag.notifier);			
  		}
  		
  		protected T getFlag() {
  			return flag.getFlag();
  		}
  		
  		/**
  		 * @param flag
  		 */
  		public abstract void execute(T flagValue);
  		
  		/**
  		 * @param flag
  		 */
  		public abstract void execute(T flagValue, R reason);
  		
  	}
  	
  	public FlagInteger() {
  		super(0);
  	}
  	
  	public FlagInteger(Integer initial) {
  		super(initial);
  	}
  	
  	public void increment(final int number) {
  		inSync(
  			new DoInSync<Integer>() {
  	
  				@Override
  				public void execute(Integer flagValue) {
  					setFlag(flagValue+number);
  				}
  				
  			}
  		);
  	}
  	
  	public void decrement(final int number) {
  		inSync(
  			new DoInSync<Integer>() {
  	
  				@Override
  				public void execute(Integer flagValue) {
  					setFlag(flagValue-number);
  				}
  				
  			}
  		);
  	}
  
  }