org.apache.xalan.lib.ExsltMath Maven / Gradle / Ivy
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/*
* 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.
*/
/*
* $Id: ExsltMath.java 468639 2006-10-28 06:52:33Z minchau $
*/
package org.apache.xalan.lib;
import org.apache.xpath.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:
*
* xmlns:math="http://exslt.org/math"
*
*
* The documentation for each function has been copied from the relevant
* EXSLT Implementer page.
*
* @see EXSLT
* @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.
*
* 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 EXSLT
*/
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.
*
* 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 EXSLT
*/
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.
*
* 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.
*
* 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:
*
* PI
* E
* SQRRT2
* LN2
* LN10
* LOG2E
* SQRT1_2
*
* @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 = new Double(precision).intValue();
if (bits <= value.length())
value = value.substring(0, bits);
return new Double(value).doubleValue();
}
else
return Double.NaN;
}
}