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Commons Math example source code file (ComplexFormat.java)

This example Commons Math source code file (ComplexFormat.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Commons Math tags/keywords

complex, complex, complexformat, complexformat, fieldposition, number, numberformat, numberformat, override, parseexception, parseposition, string, stringbuffer, stringbuffer, text, util

The Commons Math ComplexFormat.java source code

/*
 * 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 org.apache.commons.math.complex;

import java.text.FieldPosition;
import java.text.NumberFormat;
import java.text.ParseException;
import java.text.ParsePosition;
import java.util.Locale;

import org.apache.commons.math.MathRuntimeException;
import org.apache.commons.math.util.CompositeFormat;

/**
 * Formats a Complex number in cartesian format "Re(c) + Im(c)i".  'i' can
 * be replaced with 'j' (or anything else), and the number format for both real
 * and imaginary parts can be configured.
 *
 * @version $Revision: 811783 $ $Date: 2009-09-06 04:56:58 -0400 (Sun, 06 Sep 2009) $
 */
public class ComplexFormat extends CompositeFormat {

    /** Serializable version identifier */
    private static final long serialVersionUID = -3343698360149467646L;

     /** The default imaginary character. */
    private static final String DEFAULT_IMAGINARY_CHARACTER = "i";

    /** The notation used to signify the imaginary part of the complex number. */
    private String imaginaryCharacter;

    /** The format used for the imaginary part. */
    private NumberFormat imaginaryFormat;

    /** The format used for the real part. */
    private NumberFormat realFormat;

    /**
     * Create an instance with the default imaginary character, 'i', and the
     * default number format for both real and imaginary parts.
     */
    public ComplexFormat() {
        this(DEFAULT_IMAGINARY_CHARACTER, getDefaultNumberFormat());
    }

    /**
     * Create an instance with a custom number format for both real and
     * imaginary parts.
     * @param format the custom format for both real and imaginary parts.
     */
    public ComplexFormat(NumberFormat format) {
        this(DEFAULT_IMAGINARY_CHARACTER, format);
    }

    /**
     * Create an instance with a custom number format for the real part and a
     * custom number format for the imaginary part.
     * @param realFormat the custom format for the real part.
     * @param imaginaryFormat the custom format for the imaginary part.
     */
    public ComplexFormat(NumberFormat realFormat, NumberFormat imaginaryFormat) {
        this(DEFAULT_IMAGINARY_CHARACTER, realFormat, imaginaryFormat);
    }

    /**
     * Create an instance with a custom imaginary character, and the default
     * number format for both real and imaginary parts.
     * @param imaginaryCharacter The custom imaginary character.
     */
    public ComplexFormat(String imaginaryCharacter) {
        this(imaginaryCharacter, getDefaultNumberFormat());
    }

    /**
     * Create an instance with a custom imaginary character, and a custom number
     * format for both real and imaginary parts.
     * @param imaginaryCharacter The custom imaginary character.
     * @param format the custom format for both real and imaginary parts.
     */
    public ComplexFormat(String imaginaryCharacter, NumberFormat format) {
        this(imaginaryCharacter, format, (NumberFormat)format.clone());
    }

    /**
     * Create an instance with a custom imaginary character, a custom number
     * format for the real part, and a custom number format for the imaginary
     * part.
     * @param imaginaryCharacter The custom imaginary character.
     * @param realFormat the custom format for the real part.
     * @param imaginaryFormat the custom format for the imaginary part.
     */
    public ComplexFormat(String imaginaryCharacter, NumberFormat realFormat,
            NumberFormat imaginaryFormat) {
        super();
        setImaginaryCharacter(imaginaryCharacter);
        setImaginaryFormat(imaginaryFormat);
        setRealFormat(realFormat);
    }

    /**
     * Get the set of locales for which complex formats are available.
     * <p>This is the same set as the {@link NumberFormat} set.

* @return available complex format locales. */ public static Locale[] getAvailableLocales() { return NumberFormat.getAvailableLocales(); } /** * This static method calls {@link #format(Object)} on a default instance of * ComplexFormat. * * @param c Complex object to format * @return A formatted number in the form "Re(c) + Im(c)i" */ public static String formatComplex(Complex c) { return getInstance().format(c); } /** * Formats a {@link Complex} object to produce a string. * * @param complex the object to format. * @param toAppendTo where the text is to be appended * @param pos On input: an alignment field, if desired. On output: the * offsets of the alignment field * @return the value passed in as toAppendTo. */ public StringBuffer format(Complex complex, StringBuffer toAppendTo, FieldPosition pos) { pos.setBeginIndex(0); pos.setEndIndex(0); // format real double re = complex.getReal(); formatDouble(re, getRealFormat(), toAppendTo, pos); // format sign and imaginary double im = complex.getImaginary(); if (im < 0.0) { toAppendTo.append(" - "); formatDouble(-im, getImaginaryFormat(), toAppendTo, pos); toAppendTo.append(getImaginaryCharacter()); } else if (im > 0.0 || Double.isNaN(im)) { toAppendTo.append(" + "); formatDouble(im, getImaginaryFormat(), toAppendTo, pos); toAppendTo.append(getImaginaryCharacter()); } return toAppendTo; } /** * Formats a object to produce a string. <code>obj must be either a * {@link Complex} object or a {@link Number} object. Any other type of * object will result in an {@link IllegalArgumentException} being thrown. * * @param obj the object to format. * @param toAppendTo where the text is to be appended * @param pos On input: an alignment field, if desired. On output: the * offsets of the alignment field * @return the value passed in as toAppendTo. * @see java.text.Format#format(java.lang.Object, java.lang.StringBuffer, java.text.FieldPosition) * @throws IllegalArgumentException is <code>obj is not a valid type. */ @Override public StringBuffer format(Object obj, StringBuffer toAppendTo, FieldPosition pos) { StringBuffer ret = null; if (obj instanceof Complex) { ret = format( (Complex)obj, toAppendTo, pos); } else if (obj instanceof Number) { ret = format( new Complex(((Number)obj).doubleValue(), 0.0), toAppendTo, pos); } else { throw MathRuntimeException.createIllegalArgumentException( "cannot format a {0} instance as a complex number", obj.getClass().getName()); } return ret; } /** * Access the imaginaryCharacter. * @return the imaginaryCharacter. */ public String getImaginaryCharacter() { return imaginaryCharacter; } /** * Access the imaginaryFormat. * @return the imaginaryFormat. */ public NumberFormat getImaginaryFormat() { return imaginaryFormat; } /** * Returns the default complex format for the current locale. * @return the default complex format. */ public static ComplexFormat getInstance() { return getInstance(Locale.getDefault()); } /** * Returns the default complex format for the given locale. * @param locale the specific locale used by the format. * @return the complex format specific to the given locale. */ public static ComplexFormat getInstance(Locale locale) { NumberFormat f = getDefaultNumberFormat(locale); return new ComplexFormat(f); } /** * Access the realFormat. * @return the realFormat. */ public NumberFormat getRealFormat() { return realFormat; } /** * Parses a string to produce a {@link Complex} object. * * @param source the string to parse * @return the parsed {@link Complex} object. * @exception ParseException if the beginning of the specified string * cannot be parsed. */ public Complex parse(String source) throws ParseException { ParsePosition parsePosition = new ParsePosition(0); Complex result = parse(source, parsePosition); if (parsePosition.getIndex() == 0) { throw MathRuntimeException.createParseException( parsePosition.getErrorIndex(), "unparseable complex number: \"{0}\"", source); } return result; } /** * Parses a string to produce a {@link Complex} object. * * @param source the string to parse * @param pos input/ouput parsing parameter. * @return the parsed {@link Complex} object. */ public Complex parse(String source, ParsePosition pos) { int initialIndex = pos.getIndex(); // parse whitespace parseAndIgnoreWhitespace(source, pos); // parse real Number re = parseNumber(source, getRealFormat(), pos); if (re == null) { // invalid real number // set index back to initial, error index should already be set pos.setIndex(initialIndex); return null; } // parse sign int startIndex = pos.getIndex(); char c = parseNextCharacter(source, pos); int sign = 0; switch (c) { case 0 : // no sign // return real only complex number return new Complex(re.doubleValue(), 0.0); case '-' : sign = -1; break; case '+' : sign = 1; break; default : // invalid sign // set index back to initial, error index should be the last // character examined. pos.setIndex(initialIndex); pos.setErrorIndex(startIndex); return null; } // parse whitespace parseAndIgnoreWhitespace(source, pos); // parse imaginary Number im = parseNumber(source, getRealFormat(), pos); if (im == null) { // invalid imaginary number // set index back to initial, error index should already be set pos.setIndex(initialIndex); return null; } // parse imaginary character if (!parseFixedstring(source, getImaginaryCharacter(), pos)) { return null; } return new Complex(re.doubleValue(), im.doubleValue() * sign); } /** * Parses a string to produce a object. * * @param source the string to parse * @param pos input/ouput parsing parameter. * @return the parsed object. * @see java.text.Format#parseObject(java.lang.String, java.text.ParsePosition) */ @Override public Object parseObject(String source, ParsePosition pos) { return parse(source, pos); } /** * Modify the imaginaryCharacter. * @param imaginaryCharacter The new imaginaryCharacter value. * @throws IllegalArgumentException if <code>imaginaryCharacter is * <code>null or an empty string. */ public void setImaginaryCharacter(String imaginaryCharacter) { if (imaginaryCharacter == null || imaginaryCharacter.length() == 0) { throw MathRuntimeException.createIllegalArgumentException( "empty string for imaginary character"); } this.imaginaryCharacter = imaginaryCharacter; } /** * Modify the imaginaryFormat. * @param imaginaryFormat The new imaginaryFormat value. * @throws IllegalArgumentException if <code>imaginaryFormat is * <code>null. */ public void setImaginaryFormat(NumberFormat imaginaryFormat) { if (imaginaryFormat == null) { throw MathRuntimeException.createIllegalArgumentException( "null imaginary format"); } this.imaginaryFormat = imaginaryFormat; } /** * Modify the realFormat. * @param realFormat The new realFormat value. * @throws IllegalArgumentException if <code>realFormat is * <code>null. */ public void setRealFormat(NumberFormat realFormat) { if (realFormat == null) { throw MathRuntimeException.createIllegalArgumentException( "null real format"); } this.realFormat = realFormat; } }

Other Commons Math examples (source code examples)

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