/src/main/java/org/andya/confluence/utils/MathUtils.java

/*

 * Copyright (c) 2006, 2007 Andy Armstrong, Kelsey Grant and other contributors.

 * All rights reserved.

 * 

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions are met:

 * 

 *     * Redistributions of source code must retain the above copyright notice,

 *       this list of conditions and the following disclaimer.

 *     * Redistributions in binary form must reproduce the above copyright notice,

 *       this list of conditions and the following disclaimer in the documentation

 *       and/or other materials provided with the distribution.

 *     * The names of contributors may not

 *       be used to endorse or promote products derived from this software without

 *       specific prior written permission.

 * 

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR

 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON

 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */



package org.andya.confluence.utils;



import com.atlassian.renderer.v2.macro.MacroException;



import java.util.List;



/**

 * Useful math utilities for use in macros.

 */

public class MathUtils {

	/**

	 * Parse a string as a number in the following order: 1. If the value is in

	 * Confluence duration format return a {@link Duration}. 2. If the value is

	 * an Integer return an integer. 3. If all else fails try to parse the

	 * number as a double.

	 */

	public static Number parseNumber(String value) {

		Duration duration = Duration.parseDuration(value);

		if (duration != null)

			return duration;

		try {

			// clean the value by stripping out non digits.

			// this lets people put $ signs and other misc units into

			// integer fields safely.

			char[] chars = value.toCharArray();

			StringBuffer out = new StringBuffer();

			for (int i = 0; i < chars.length; i++) {

				char c = chars[i];

				if (c >= '0' && c <= '9') {

					out.append(c);

				} else if (c == '.' || c == '-') {

					out.append(c);

				}

			}



			value = out.toString();



			int intValue = Integer.parseInt(value);

			return new Integer(intValue);

		} catch (NumberFormatException e) {

			try {

				double doubleValue = Double.parseDouble(value);

				return new Double(doubleValue);

			} catch (NumberFormatException e2) {

				return null;

			}

		}

	}



	/** Converts a number to the best string representation. */

	public static String toString(Number number) {

		if (number instanceof Duration)

			return ((Duration) number).getDurationString();

		else if (number instanceof Integer)

			return Integer.toString(number.intValue());

		else

			return Double.toString(number.doubleValue());

	}



	/** Apply the specified function to a list of values. */

	public static Number doCalculation(String function, List<Number> values)

			throws MacroException {

		function = function.trim().toLowerCase();

		if ("sum".equals(function))

			return sum(values);

		else if ("avg".equals(function) || "average".equals(function))

			return average(values);

		else if ("min".equals(function) || "minimum".equals(function))

			return min(values);

		else if ("max".equals(function) || "maximum".equals(function))

			return max(values);

		throw new MacroException("Unknown function \"" + function + "\"");

	}



	/** Calculate the sum of a list of numbers. */

	public static Number sum(List<Number> values) {

		double sum = 0;

		boolean integerOnly = true;

		boolean duration = false;

		for (Number number : values) {

			if (number instanceof Double)

				integerOnly = false;

			else if (number instanceof Duration)

				duration = true;

			sum += number.doubleValue();

		}

		if (duration)

			return new Duration((long) sum);

		if (integerOnly)

			return new Integer((int) sum);

		return new Double(sum);

	}



	/** Calculate the average of a list of numbers. */

	public static Number average(List<Number> values) {

		Number total = sum(values);

		double average = total.doubleValue() / values.size();

		if (total instanceof Duration)

			return new Duration((long) average);

		return new Double(average);

	}



	/** Calculate the minimum of a list of numbers. */

	public static Number min(List<Number> values) {

		double min = Double.MAX_VALUE;

		boolean integerOnly = true;

		boolean duration = false;

		for (Number number : values) {

			if (number instanceof Duration)

				duration = true;

			else if (number instanceof Double)

				integerOnly = false;

			min = Math.min(min, number.doubleValue());

		}

		if (duration)

			return new Duration((long) min);

		else if (integerOnly)

			return new Integer((int) min);

		return new Double(min);

	}



	/** Calculate the maximum of a list of numbers. */

	public static Number max(List<Number> values) {

		double max = Double.MIN_VALUE;

		boolean integerOnly = true;

		boolean duration = false;

		for (Number number : values) {

			if (number instanceof Duration)

				duration = true;

			else if (number instanceof Double)

				integerOnly = false;

			max = Math.max(max, number.doubleValue());

		}

		if (duration)

			return new Duration((long) max);

		if (integerOnly)

			return new Integer((int) max);

		return new Double(max);

	}

}