/*
 *     file: FinalCollections.java
 *  package: oreilly.hcj.finalstory
 *
 * This software is granted under the terms of the Common Public License,
 * CPL, which may be found at the following URL:
 * http://www-124.ibm.com/developerworks/oss/CPLv1.0.htm
 *
 * Copyright(c) 2003-2005 by the authors indicated in the @author tags.
 * All Rights are Reserved by the various authors.
 *
########## DO NOT EDIT ABOVE THIS LINE ########## */

package oreilly.hcj.finalstory;

import java.awt.Color;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;

/**  
 * Demonstrates the use of final collections.
 *
 * @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
 * @version $Revision: 1.3 $
 */
public class FinalCollections {
	/** 
	 * Main method for demonstration.
	 *
	 * @param args Command line arguments.
	 */
	public static final void main(final String[] args) {
		Rainbow.someMethod();
		System.out.println("------------------");
		try {
			RainbowBetter.someMethod();
		} catch (final UnsupportedOperationException ex) {
			ex.printStackTrace(System.out);
			System.out.println("Told you it would exception =)");
		}
	}

	/**  
	 * A class that demonstrates the rainbow.
	 *
	 * @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
	 * @version $Revision: 1.3 $
	 */
	public static class Rainbow {
		/** The set of valid colors of the rainbow. */
		public static final Set VALID_COLORS;

		static {
			VALID_COLORS = new HashSet();
			VALID_COLORS.add(Color.red);
			VALID_COLORS.add(Color.orange);
			VALID_COLORS.add(Color.yellow);
			VALID_COLORS.add(Color.green);
			VALID_COLORS.add(Color.blue);
			VALID_COLORS.add(Color.decode("#4B0082"));  // indigo
			VALID_COLORS.add(Color.decode("#8A2BE2"));  // violet
		}

		/** 
		 * A demo method.
		 */
		public static final void someMethod() {
			Set colors = Rainbow.VALID_COLORS;
			colors.add(Color.black);  // <= logic error but allowed by compiler
			System.out.println(colors);
		}
	}

	/**  
	 * A better version of the rainbow class using an unmodifiable set.
	 *
	 * @author <a href=mailto:kraythe@arcor.de>Robert Simmons jr. (kraythe)</a>
	 * @version $Revision: 1.3 $
	 */
	public static class RainbowBetter {
		/** The valid colors of the rainbow. */
		public static final Set VALID_COLORS;

		static {
			Set temp = new HashSet();
			temp.add(Color.red);
			temp.add(Color.orange);
			temp.add(Color.yellow);
			temp.add(Color.green);
			temp.add(Color.blue);
			temp.add(Color.decode("#4B0082"));  // indigo
			temp.add(Color.decode("#8A2BE2"));  // violet
			VALID_COLORS = Collections.unmodifiableSet(temp);
		}

		/** 
		 * Some demo method.
		 */
		public static final void someMethod() {
			Set colors = RainbowBetter.VALID_COLORS;
			colors.add(Color.black);  // <= exception here
			System.out.println(colors);
		}
	}
}

/* ########## End of File ########## */