| /* |
| * 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. |
| */ |
| /* |
| * $Id$ |
| */ |
| 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: |
| * <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 = new Double(precision).intValue(); |
| |
| if (bits <= value.length()) |
| value = value.substring(0, bits); |
| |
| return new Double(value).doubleValue(); |
| } |
| else |
| return Double.NaN; |
| |
| } |
| |
| } |