package cz.cuni.amis.pogamut.base.utils.logging;
   
   import java.util.HashSet;
   import java.util.Set;
   import java.util.logging.Filter;
   import java.util.logging.LogRecord;
   
   /**
    * Simple filter for LogCategory - it is instantiated with the instance
   * of the LogCategory (or array of them) which it should accept.
   * 
   * @author Jimmy
   */
  public class LogCategoryFilter implements Filter {
  	
  	private interface Filter {
  		public boolean isLoggable(LogRecord record);
  	}
  	
  	private class LogSingleCategoryFilter implements Filter {
  		
  		public boolean isLoggable(LogRecord record) {
  			return record.getParameters() != null && record.getParameters().length > 0 && record.getParameters()[0] == category; 
  		}
  		
  	}
  	
  	private class LogMultipleCategoriesFilter implements Filter {
  		
  		public boolean isLoggable(LogRecord record) {
  			return record.getParameters() != null && record.getParameters().length > 0 && categories.contains(record.getParameters()[0]); 
  		}
  		
  	}
  	
  	private LogCategory category = null;
  	
  	private Filter filter;
  	
  	private Set<LogCategory> categories = null;
  	
  	public LogCategoryFilter(LogCategory category) {
  		this.category = category;
  		filter = new LogSingleCategoryFilter();
  	}
  	
  	public LogCategoryFilter(LogCategory[] categories) {
  		this.categories = new HashSet<LogCategory>();
  		for (LogCategory category : categories) {
  			this.categories.add(category);
  		}
  		filter = new LogMultipleCategoriesFilter();
  	}
  
  	@Override
  	public boolean isLoggable(LogRecord record) {
  		return filter.isLoggable(record); 
  	}
  	
  	/**
  	 * Returns cathegories the filter is looking for (taking / allowing the log record to be published).
  	 * <p><p>
  	 * This array is copy - altering it won't alter the filter.
  	 *  
  	 * @return
  	 */
  	public LogCategory[] getFilterCategories() {
  		if (category != null) return new LogCategory[]{category};
  		return categories.toArray(new LogCategory[categories.size()]);
  	}
  
  }