Back to index...

	/*
	* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
	*/
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.sun.org.apache.xalan.internal.lib;

	import com.sun.org.apache.xpath.internal.NodeSet;

	import org.w3c.dom.Node;
	import org.w3c.dom.NodeList;

	/**
	* This class contains EXSLT math extension functions.
	* It is accessed by specifying a namespace URI as follows:
	* <pre>
	* xmlns:math="http://exslt.org/math"
	* </pre>
	*
	* The documentation for each function has been copied from the relevant
	* EXSLT Implementer page.
	*
	* @see <a href="http://www.exslt.org/">EXSLT</a>

	* @xsl.usage general
	*/
	public class ExsltMath extends ExsltBase
	{
	// Constants
	private static String PI = "3.1415926535897932384626433832795028841971693993751";
	private static String E = "2.71828182845904523536028747135266249775724709369996";
	private static String SQRRT2 = "1.41421356237309504880168872420969807856967187537694";
	private static String LN2 = "0.69314718055994530941723212145817656807550013436025";
	private static String LN10 = "2.302585092994046";
	private static String LOG2E = "1.4426950408889633";
	private static String SQRT1_2 = "0.7071067811865476";

	/**
	* The math:max function returns the maximum value of the nodes passed as the argument.
	* The maximum value is defined as follows. The node set passed as an argument is sorted
	* in descending order as it would be by xsl:sort with a data type of number. The maximum
	* is the result of converting the string value of the first node in this sorted list to
	* a number using the number function.
	* <p>
	* If the node set is empty, or if the result of converting the string values of any of the
	* nodes to a number is NaN, then NaN is returned.
	*
	* @param nl The NodeList for the node-set to be evaluated.
	*
	* @return the maximum value found, NaN if any node cannot be converted to a number.
	*
	* @see <a href="http://www.exslt.org/">EXSLT</a>
	*/
	public static double max (NodeList nl)
	{
	if (nl == null \|\| nl.getLength() == 0)
	return Double.NaN;

	double m = - Double.MAX_VALUE;
	for (int i = 0; i < nl.getLength(); i++)
	{
	Node n = nl.item(i);
	double d = toNumber(n);
	if (Double.isNaN(d))
	return Double.NaN;
	else if (d > m)
	m = d;
	}

	return m;
	}

	/**
	* The math:min function returns the minimum value of the nodes passed as the argument.
	* The minimum value is defined as follows. The node set passed as an argument is sorted
	* in ascending order as it would be by xsl:sort with a data type of number. The minimum
	* is the result of converting the string value of the first node in this sorted list to
	* a number using the number function.
	* <p>
	* If the node set is empty, or if the result of converting the string values of any of
	* the nodes to a number is NaN, then NaN is returned.
	*
	* @param nl The NodeList for the node-set to be evaluated.
	*
	* @return the minimum value found, NaN if any node cannot be converted to a number.
	*
	* @see <a href="http://www.exslt.org/">EXSLT</a>
	*/
	public static double min (NodeList nl)
	{
	if (nl == null \|\| nl.getLength() == 0)
	return Double.NaN;

	double m = Double.MAX_VALUE;
	for (int i = 0; i < nl.getLength(); i++)
	{
	Node n = nl.item(i);
	double d = toNumber(n);
	if (Double.isNaN(d))
	return Double.NaN;
	else if (d < m)
	m = d;
	}

	return m;
	}

	/**
	* The math:highest function returns the nodes in the node set whose value is the maximum
	* value for the node set. The maximum value for the node set is the same as the value as
	* calculated by math:max. A node has this maximum value if the result of converting its
	* string value to a number as if by the number function is equal to the maximum value,
	* where the equality comparison is defined as a numerical comparison using the = operator.
	* <p>
	* If any of the nodes in the node set has a non-numeric value, the math:max function will
	* return NaN. The definition numeric comparisons entails that NaN != NaN. Therefore if any
	* of the nodes in the node set has a non-numeric value, math:highest will return an empty
	* node set.
	*
	* @param nl The NodeList for the node-set to be evaluated.
	*
	* @return node-set with nodes containing the maximum value found, an empty node-set
	* if any node cannot be converted to a number.
	*/
	public static NodeList highest (NodeList nl)
	{
	double maxValue = max(nl);

	NodeSet highNodes = new NodeSet();
	highNodes.setShouldCacheNodes(true);

	if (Double.isNaN(maxValue))
	return highNodes; // empty Nodeset

	for (int i = 0; i < nl.getLength(); i++)
	{
	Node n = nl.item(i);
	double d = toNumber(n);
	if (d == maxValue)
	highNodes.addElement(n);
	}
	return highNodes;
	}

	/**
	* The math:lowest function returns the nodes in the node set whose value is the minimum value
	* for the node set. The minimum value for the node set is the same as the value as calculated
	* by math:min. A node has this minimum value if the result of converting its string value to
	* a number as if by the number function is equal to the minimum value, where the equality
	* comparison is defined as a numerical comparison using the = operator.
	* <p>
	* If any of the nodes in the node set has a non-numeric value, the math:min function will return
	* NaN. The definition numeric comparisons entails that NaN != NaN. Therefore if any of the nodes
	* in the node set has a non-numeric value, math:lowest will return an empty node set.
	*
	* @param nl The NodeList for the node-set to be evaluated.
	*
	* @return node-set with nodes containing the minimum value found, an empty node-set
	* if any node cannot be converted to a number.
	*
	*/
	public static NodeList lowest (NodeList nl)
	{
	double minValue = min(nl);

	NodeSet lowNodes = new NodeSet();
	lowNodes.setShouldCacheNodes(true);

	if (Double.isNaN(minValue))
	return lowNodes; // empty Nodeset

	for (int i = 0; i < nl.getLength(); i++)
	{
	Node n = nl.item(i);
	double d = toNumber(n);
	if (d == minValue)
	lowNodes.addElement(n);
	}
	return lowNodes;
	}

	/**
	* The math:abs function returns the absolute value of a number.
	*
	* @param num A number
	* @return The absolute value of the number
	*/
	public static double abs(double num)
	{
	return Math.abs(num);
	}

	/**
	* The math:acos function returns the arccosine value of a number.
	*
	* @param num A number
	* @return The arccosine value of the number
	*/
	public static double acos(double num)
	{
	return Math.acos(num);
	}

	/**
	* The math:asin function returns the arcsine value of a number.
	*
	* @param num A number
	* @return The arcsine value of the number
	*/
	public static double asin(double num)
	{
	return Math.asin(num);
	}

	/**
	* The math:atan function returns the arctangent value of a number.
	*
	* @param num A number
	* @return The arctangent value of the number
	*/
	public static double atan(double num)
	{
	return Math.atan(num);
	}

	/**
	* The math:atan2 function returns the angle ( in radians ) from the X axis to a point (y,x).
	*
	* @param num1 The X axis value
	* @param num2 The Y axis value
	* @return The angle (in radians) from the X axis to a point (y,x)
	*/
	public static double atan2(double num1, double num2)
	{
	return Math.atan2(num1, num2);
	}

	/**
	* The math:cos function returns cosine of the passed argument.
	*
	* @param num A number
	* @return The cosine value of the number
	*/
	public static double cos(double num)
	{
	return Math.cos(num);
	}

	/**
	* The math:exp function returns e (the base of natural logarithms) raised to a power.
	*
	* @param num A number
	* @return The value of e raised to the given power
	*/
	public static double exp(double num)
	{
	return Math.exp(num);
	}

	/**
	* The math:log function returns the natural logarithm of a number.
	*
	* @param num A number
	* @return The natural logarithm of the number
	*/
	public static double log(double num)
	{
	return Math.log(num);
	}

	/**
	* The math:power function returns the value of a base expression taken to a specified power.
	*
	* @param num1 The base
	* @param num2 The power
	* @return The value of the base expression taken to the specified power
	*/
	public static double power(double num1, double num2)
	{
	return Math.pow(num1, num2);
	}

	/**
	* The math:random function returns a random number from 0 to 1.
	*
	* @return A random double from 0 to 1
	*/
	public static double random()
	{
	return Math.random();
	}

	/**
	* The math:sin function returns the sine of the number.
	*
	* @param num A number
	* @return The sine value of the number
	*/
	public static double sin(double num)
	{
	return Math.sin(num);
	}

	/**
	* The math:sqrt function returns the square root of a number.
	*
	* @param num A number
	* @return The square root of the number
	*/
	public static double sqrt(double num)
	{
	return Math.sqrt(num);
	}

	/**
	* The math:tan function returns the tangent of the number passed as an argument.
	*
	* @param num A number
	* @return The tangent value of the number
	*/
	public static double tan(double num)
	{
	return Math.tan(num);
	}

	/**
	* The math:constant function returns the specified constant to a set precision.
	* The possible constants are:
	* <pre>
	* PI
	* E
	* SQRRT2
	* LN2
	* LN10
	* LOG2E
	* SQRT1_2
	* </pre>
	* @param name The name of the constant
	* @param precision The precision
	* @return The value of the specified constant to the given precision
	*/
	public static double constant(String name, double precision)
	{
	String value = null;
	if (name.equals("PI"))
	value = PI;
	else if (name.equals("E"))
	value = E;
	else if (name.equals("SQRRT2"))
	value = SQRRT2;
	else if (name.equals("LN2"))
	value = LN2;
	else if (name.equals("LN10"))
	value = LN10;
	else if (name.equals("LOG2E"))
	value = LOG2E;
	else if (name.equals("SQRT1_2"))
	value = SQRT1_2;

	if (value != null)
	{
	int bits = (int)precision;

	if (bits <= value.length())
	value = value.substring(0, bits);

	return Double.parseDouble(value);
	}
	else
	return Double.NaN;

	}

	}

Back to index...