/*
 This file is part of the software framework JStatCom, 
 a library for building applications for data based analysis.

 Copyright (C) 2000-2005  Markus Kraetzig

 This library is free software; you can redistribute it and/or modify
 it under the terms of the GNU Lesser General Public License as
 published by the Free Software Foundation; either version 2.1 of the
 License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful, but
 WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 USA
 */

package com.jstatcom.model;
/**
 * This class contains an enumeration of constants that define different
 * types of number ranges.
 * 

 * It implements the typesave enum pattern (Joshua Bloch, "Effective Java", Item 21).
 * If you compare NumberRangeTypes, always use the == operator. This is
 * save, because they are Singletons (Gamma et al., 1995).  
 *
 * @author Markus Kraetzig
 */
public class NumberRangeTypes {
	/**
	 * "(" (not inclusive) or "[" (inclusive). 
	 */
	public final String leftBracket;
	/**
	 * ")" (not inclusive) or "]" (inclusive). 
	 */
	public final String rightBracket;
	/**
	 * Whether lower bound is open.
	 */
	public final boolean leftOpen;
	/**
	 * Whether upper bound is open.
	 */
	public final boolean rightOpen;
	/**
	 * The name of the type.
	 */
	private final String name;

	/**
	 * Type for closed interval.
	 */
	public static final NumberRangeTypes CLOSED =
		new NumberRangeTypes("CLOSED", false, false);
	/**
	 * Type for open interval.
	 */
	public static final NumberRangeTypes OPEN =
		new NumberRangeTypes("OPEN", true, true);
	/**
	 * Type for left-open interval.
	 */
	public static final NumberRangeTypes LEFT_OPEN =
		new NumberRangeTypes("LEFT_OPEN", true, false);
	/**
	 * Type for right-open interval.
	 */
	public static final NumberRangeTypes RIGHT_OPEN =
		new NumberRangeTypes("RIGHT_OPEN", false, true);

	/**
	 * NumberRangeTypes constructor with a descriptive name
	 * and the bounds settings.
	 *
	 * @param name a descriptive name
	 * @param leftOpen true if lower bound is open
	 * @param rightopen true if upper bound is open
	 */
	private NumberRangeTypes(
		String name,
		boolean leftOpen,
		boolean rightOpen) {
		this.name = name;
		this.leftOpen = leftOpen;
		this.rightOpen = rightOpen;
		this.leftBracket = leftOpen ? "(" : "[";
		this.rightBracket = rightOpen ? ")" : "]";
	}

	/**
	 * Gets the strimg for the left bracket.
	 * 
	 * @return "(" or "["
	 */
	public final String leftBracket() {
		return leftBracket;
	}

	/**
	 * Returns the name of the type. Do not use for comparisons,
	 * but compare by reference.
	 *
	 * @return name of this type
	 */
	public final String name() {
		return name;
	}

	/**
	 * Gets the strimg for the right bracket.
	 * 
	 * @return ")" or "]"
	 */
	public final String rightBracket() {
		return rightBracket;
	}

	/**
	 * Gets the appropriate range type according to the specification
	 * of the bounds openess.
	 * 
	 * @param leftOpen whether lower bound is open 
	 * @param rightOpen whether upper bound is open 
	 * @return number range type
	 */
	public static final NumberRangeTypes getTypeForBounds(
		boolean leftOpen,
		boolean rightOpen) {

		if (leftOpen && rightOpen)
			return OPEN;
		if (!leftOpen && !rightOpen)
			return CLOSED;
		if (!leftOpen && rightOpen)
			return RIGHT_OPEN;
		if (leftOpen && !rightOpen)
			return LEFT_OPEN;

		throw new RuntimeException("Code should never be reached.");
	}

	/**
	 * Gets whether left bound is open.
	 * 
	 * @return true if left bound is open
	 */
	public final boolean isLeftOpen() {
		return leftOpen;
	}

	/**
	 * Gets whether right bound is open.
	 * 
	 * @return true if right bound is open
	 */
	public final boolean isRightOpen() {
		return rightOpen;
	}

	/**
	 * Returns a string representation of the type, do not use for comparisons.
	 *
	 * @return string representing this type
	 */
	public final String toString() {
		return name + " " + leftBracket + "lower, upper" + rightBracket;

	}
}