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Java example source code file (ChoiceFormat.java)
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The ChoiceFormat.java Java example source code
/*
* Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* (C) Copyright Taligent, Inc. 1996, 1997 - All Rights Reserved
* (C) Copyright IBM Corp. 1996 - 1998 - All Rights Reserved
*
* The original version of this source code and documentation is copyrighted
* and owned by Taligent, Inc., a wholly-owned subsidiary of IBM. These
* materials are provided under terms of a License Agreement between Taligent
* and Sun. This technology is protected by multiple US and International
* patents. This notice and attribution to Taligent may not be removed.
* Taligent is a registered trademark of Taligent, Inc.
*
*/
package java.text;
import java.io.InvalidObjectException;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.util.Arrays;
/**
* A <code>ChoiceFormat allows you to attach a format to a range of numbers.
* It is generally used in a <code>MessageFormat for handling plurals.
* The choice is specified with an ascending list of doubles, where each item
* specifies a half-open interval up to the next item:
* <blockquote>
* <pre>
* X matches j if and only if limit[j] ? X < limit[j+1]
* </pre>
* </blockquote>
* If there is no match, then either the first or last index is used, depending
* on whether the number (X) is too low or too high. If the limit array is not
* in ascending order, the results of formatting will be incorrect. ChoiceFormat
* also accepts <code>\u221E as equivalent to infinity(INF).
*
* <p>
* <strong>Note:
* <code>ChoiceFormat differs from the other Format
* classes in that you create a <code>ChoiceFormat object with a
* constructor (not with a <code>getInstance style factory
* method). The factory methods aren't necessary because <code>ChoiceFormat
* doesn't require any complex setup for a given locale. In fact,
* <code>ChoiceFormat doesn't implement any locale specific behavior.
*
* <p>
* When creating a <code>ChoiceFormat, you must specify an array of formats
* and an array of limits. The length of these arrays must be the same.
* For example,
* <ul>
* <li>
* <em>limits = {1,2,3,4,5,6,7}
* <em>formats = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"}
* <li>
* <em>limits = {0, 1, ChoiceFormat.nextDouble(1)}
* <em>formats = {"no files", "one file", "many files"}
* (<code>nextDouble can be used to get the next higher double, to
* make the half-open interval.)
* </ul>
*
* <p>
* Here is a simple example that shows formatting and parsing:
* <blockquote>
* <pre>{@code
* double[] limits = {1,2,3,4,5,6,7};
* String[] dayOfWeekNames = {"Sun","Mon","Tue","Wed","Thur","Fri","Sat"};
* ChoiceFormat form = new ChoiceFormat(limits, dayOfWeekNames);
* ParsePosition status = new ParsePosition(0);
* for (double i = 0.0; i <= 8.0; ++i) {
* status.setIndex(0);
* System.out.println(i + " -> " + form.format(i) + " -> "
* + form.parse(form.format(i),status));
* }
* }</pre>
* </blockquote>
* Here is a more complex example, with a pattern format:
* <blockquote>
* <pre>{@code
* double[] filelimits = {0,1,2};
* String[] filepart = {"are no files","is one file","are {2} files"};
* ChoiceFormat fileform = new ChoiceFormat(filelimits, filepart);
* Format[] testFormats = {fileform, null, NumberFormat.getInstance()};
* MessageFormat pattform = new MessageFormat("There {0} on {1}");
* pattform.setFormats(testFormats);
* Object[] testArgs = {null, "ADisk", null};
* for (int i = 0; i < 4; ++i) {
* testArgs[0] = new Integer(i);
* testArgs[2] = testArgs[0];
* System.out.println(pattform.format(testArgs));
* }
* }</pre>
* </blockquote>
* <p>
* Specifying a pattern for ChoiceFormat objects is fairly straightforward.
* For example:
* <blockquote>
* <pre>{@code
* ChoiceFormat fmt = new ChoiceFormat(
* "-1#is negative| 0#is zero or fraction | 1#is one |1.0<is 1+ |2#is two |2Synchronization
*
* <p>
* Choice formats are not synchronized.
* It is recommended to create separate format instances for each thread.
* If multiple threads access a format concurrently, it must be synchronized
* externally.
*
*
* @see DecimalFormat
* @see MessageFormat
* @author Mark Davis
*/
public class ChoiceFormat extends NumberFormat {
// Proclaim serial compatibility with 1.1 FCS
private static final long serialVersionUID = 1795184449645032964L;
/**
* Sets the pattern.
* @param newPattern See the class description.
*/
public void applyPattern(String newPattern) {
StringBuffer[] segments = new StringBuffer[2];
for (int i = 0; i < segments.length; ++i) {
segments[i] = new StringBuffer();
}
double[] newChoiceLimits = new double[30];
String[] newChoiceFormats = new String[30];
int count = 0;
int part = 0;
double startValue = 0;
double oldStartValue = Double.NaN;
boolean inQuote = false;
for (int i = 0; i < newPattern.length(); ++i) {
char ch = newPattern.charAt(i);
if (ch=='\'') {
// Check for "''" indicating a literal quote
if ((i+1)<newPattern.length() && newPattern.charAt(i+1)==ch) {
segments[part].append(ch);
++i;
} else {
inQuote = !inQuote;
}
} else if (inQuote) {
segments[part].append(ch);
} else if (ch == '<' || ch == '#' || ch == '\u2264') {
if (segments[0].length() == 0) {
throw new IllegalArgumentException();
}
try {
String tempBuffer = segments[0].toString();
if (tempBuffer.equals("\u221E")) {
startValue = Double.POSITIVE_INFINITY;
} else if (tempBuffer.equals("-\u221E")) {
startValue = Double.NEGATIVE_INFINITY;
} else {
startValue = Double.valueOf(segments[0].toString()).doubleValue();
}
} catch (Exception e) {
throw new IllegalArgumentException();
}
if (ch == '<' && startValue != Double.POSITIVE_INFINITY &&
startValue != Double.NEGATIVE_INFINITY) {
startValue = nextDouble(startValue);
}
if (startValue <= oldStartValue) {
throw new IllegalArgumentException();
}
segments[0].setLength(0);
part = 1;
} else if (ch == '|') {
if (count == newChoiceLimits.length) {
newChoiceLimits = doubleArraySize(newChoiceLimits);
newChoiceFormats = doubleArraySize(newChoiceFormats);
}
newChoiceLimits[count] = startValue;
newChoiceFormats[count] = segments[1].toString();
++count;
oldStartValue = startValue;
segments[1].setLength(0);
part = 0;
} else {
segments[part].append(ch);
}
}
// clean up last one
if (part == 1) {
if (count == newChoiceLimits.length) {
newChoiceLimits = doubleArraySize(newChoiceLimits);
newChoiceFormats = doubleArraySize(newChoiceFormats);
}
newChoiceLimits[count] = startValue;
newChoiceFormats[count] = segments[1].toString();
++count;
}
choiceLimits = new double[count];
System.arraycopy(newChoiceLimits, 0, choiceLimits, 0, count);
choiceFormats = new String[count];
System.arraycopy(newChoiceFormats, 0, choiceFormats, 0, count);
}
/**
* Gets the pattern.
*
* @return the pattern string
*/
public String toPattern() {
StringBuffer result = new StringBuffer();
for (int i = 0; i < choiceLimits.length; ++i) {
if (i != 0) {
result.append('|');
}
// choose based upon which has less precision
// approximate that by choosing the closest one to an integer.
// could do better, but it's not worth it.
double less = previousDouble(choiceLimits[i]);
double tryLessOrEqual = Math.abs(Math.IEEEremainder(choiceLimits[i], 1.0d));
double tryLess = Math.abs(Math.IEEEremainder(less, 1.0d));
if (tryLessOrEqual < tryLess) {
result.append(""+choiceLimits[i]);
result.append('#');
} else {
if (choiceLimits[i] == Double.POSITIVE_INFINITY) {
result.append("\u221E");
} else if (choiceLimits[i] == Double.NEGATIVE_INFINITY) {
result.append("-\u221E");
} else {
result.append(""+less);
}
result.append('<');
}
// Append choiceFormats[i], using quotes if there are special characters.
// Single quotes themselves must be escaped in either case.
String text = choiceFormats[i];
boolean needQuote = text.indexOf('<') >= 0
|| text.indexOf('#') >= 0
|| text.indexOf('\u2264') >= 0
|| text.indexOf('|') >= 0;
if (needQuote) result.append('\'');
if (text.indexOf('\'') < 0) result.append(text);
else {
for (int j=0; j<text.length(); ++j) {
char c = text.charAt(j);
result.append(c);
if (c == '\'') result.append(c);
}
}
if (needQuote) result.append('\'');
}
return result.toString();
}
/**
* Constructs with limits and corresponding formats based on the pattern.
*
* @param newPattern the new pattern string
* @see #applyPattern
*/
public ChoiceFormat(String newPattern) {
applyPattern(newPattern);
}
/**
* Constructs with the limits and the corresponding formats.
*
* @param limits limits in ascending order
* @param formats corresponding format strings
* @see #setChoices
*/
public ChoiceFormat(double[] limits, String[] formats) {
setChoices(limits, formats);
}
/**
* Set the choices to be used in formatting.
* @param limits contains the top value that you want
* parsed with that format, and should be in ascending sorted order. When
* formatting X, the choice will be the i, where
* limit[i] ? X {@literal <} limit[i+1].
* If the limit array is not in ascending order, the results of formatting
* will be incorrect.
* @param formats are the formats you want to use for each limit.
* They can be either Format objects or Strings.
* When formatting with object Y,
* if the object is a NumberFormat, then ((NumberFormat) Y).format(X)
* is called. Otherwise Y.toString() is called.
*/
public void setChoices(double[] limits, String formats[]) {
if (limits.length != formats.length) {
throw new IllegalArgumentException(
"Array and limit arrays must be of the same length.");
}
choiceLimits = Arrays.copyOf(limits, limits.length);
choiceFormats = Arrays.copyOf(formats, formats.length);
}
/**
* Get the limits passed in the constructor.
* @return the limits.
*/
public double[] getLimits() {
double[] newLimits = Arrays.copyOf(choiceLimits, choiceLimits.length);
return newLimits;
}
/**
* Get the formats passed in the constructor.
* @return the formats.
*/
public Object[] getFormats() {
Object[] newFormats = Arrays.copyOf(choiceFormats, choiceFormats.length);
return newFormats;
}
// Overrides
/**
* Specialization of format. This method really calls
* <code>format(double, StringBuffer, FieldPosition)
* thus the range of longs that are supported is only equal to
* the range that can be stored by double. This will never be
* a practical limitation.
*/
public StringBuffer format(long number, StringBuffer toAppendTo,
FieldPosition status) {
return format((double)number, toAppendTo, status);
}
/**
* Returns pattern with formatted double.
* @param number number to be formatted and substituted.
* @param toAppendTo where text is appended.
* @param status ignore no useful status is returned.
*/
public StringBuffer format(double number, StringBuffer toAppendTo,
FieldPosition status) {
// find the number
int i;
for (i = 0; i < choiceLimits.length; ++i) {
if (!(number >= choiceLimits[i])) {
// same as number < choiceLimits, except catchs NaN
break;
}
}
--i;
if (i < 0) i = 0;
// return either a formatted number, or a string
return toAppendTo.append(choiceFormats[i]);
}
/**
* Parses a Number from the input text.
* @param text the source text.
* @param status an input-output parameter. On input, the
* status.index field indicates the first character of the
* source text that should be parsed. On exit, if no error
* occurred, status.index is set to the first unparsed character
* in the source text. On exit, if an error did occur,
* status.index is unchanged and status.errorIndex is set to the
* first index of the character that caused the parse to fail.
* @return A Number representing the value of the number parsed.
*/
public Number parse(String text, ParsePosition status) {
// find the best number (defined as the one with the longest parse)
int start = status.index;
int furthest = start;
double bestNumber = Double.NaN;
double tempNumber = 0.0;
for (int i = 0; i < choiceFormats.length; ++i) {
String tempString = choiceFormats[i];
if (text.regionMatches(start, tempString, 0, tempString.length())) {
status.index = start + tempString.length();
tempNumber = choiceLimits[i];
if (status.index > furthest) {
furthest = status.index;
bestNumber = tempNumber;
if (furthest == text.length()) break;
}
}
}
status.index = furthest;
if (status.index == start) {
status.errorIndex = furthest;
}
return new Double(bestNumber);
}
/**
* Finds the least double greater than {@code d}.
* If {@code NaN}, returns same value.
* <p>Used to make half-open intervals.
*
* @param d the reference value
* @return the least double value greather than {@code d}
* @see #previousDouble
*/
public static final double nextDouble (double d) {
return nextDouble(d,true);
}
/**
* Finds the greatest double less than {@code d}.
* If {@code NaN}, returns same value.
*
* @param d the reference value
* @return the greatest double value less than {@code d}
* @see #nextDouble
*/
public static final double previousDouble (double d) {
return nextDouble(d,false);
}
/**
* Overrides Cloneable
*/
public Object clone()
{
ChoiceFormat other = (ChoiceFormat) super.clone();
// for primitives or immutables, shallow clone is enough
other.choiceLimits = choiceLimits.clone();
other.choiceFormats = choiceFormats.clone();
return other;
}
/**
* Generates a hash code for the message format object.
*/
public int hashCode() {
int result = choiceLimits.length;
if (choiceFormats.length > 0) {
// enough for reasonable distribution
result ^= choiceFormats[choiceFormats.length-1].hashCode();
}
return result;
}
/**
* Equality comparision between two
*/
public boolean equals(Object obj) {
if (obj == null) return false;
if (this == obj) // quick check
return true;
if (getClass() != obj.getClass())
return false;
ChoiceFormat other = (ChoiceFormat) obj;
return (Arrays.equals(choiceLimits, other.choiceLimits)
&& Arrays.equals(choiceFormats, other.choiceFormats));
}
/**
* After reading an object from the input stream, do a simple verification
* to maintain class invariants.
* @throws InvalidObjectException if the objects read from the stream is invalid.
*/
private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException {
in.defaultReadObject();
if (choiceLimits.length != choiceFormats.length) {
throw new InvalidObjectException(
"limits and format arrays of different length.");
}
}
// ===============privates===========================
/**
* A list of lower bounds for the choices. The formatter will return
* <code>choiceFormats[i] if the number being formatted is greater than or equal to
* <code>choiceLimits[i] and less than choiceLimits[i+1].
* @serial
*/
private double[] choiceLimits;
/**
* A list of choice strings. The formatter will return
* <code>choiceFormats[i] if the number being formatted is greater than or equal to
* <code>choiceLimits[i] and less than choiceLimits[i+1].
* @serial
*/
private String[] choiceFormats;
/*
static final long SIGN = 0x8000000000000000L;
static final long EXPONENT = 0x7FF0000000000000L;
static final long SIGNIFICAND = 0x000FFFFFFFFFFFFFL;
private static double nextDouble (double d, boolean positive) {
if (Double.isNaN(d) || Double.isInfinite(d)) {
return d;
}
long bits = Double.doubleToLongBits(d);
long significand = bits & SIGNIFICAND;
if (bits < 0) {
significand |= (SIGN | EXPONENT);
}
long exponent = bits & EXPONENT;
if (positive) {
significand += 1;
// FIXME fix overflow & underflow
} else {
significand -= 1;
// FIXME fix overflow & underflow
}
bits = exponent | (significand & ~EXPONENT);
return Double.longBitsToDouble(bits);
}
*/
static final long SIGN = 0x8000000000000000L;
static final long EXPONENT = 0x7FF0000000000000L;
static final long POSITIVEINFINITY = 0x7FF0000000000000L;
/**
* Finds the least double greater than {@code d} (if {@code positive} is
* {@code true}), or the greatest double less than {@code d} (if
* {@code positive} is {@code false}).
* If {@code NaN}, returns same value.
*
* Does not affect floating-point flags,
* provided these member functions do not:
* Double.longBitsToDouble(long)
* Double.doubleToLongBits(double)
* Double.isNaN(double)
*
* @param d the reference value
* @param positive {@code true} if the least double is desired;
* {@code false} otherwise
* @return the least or greater double value
*/
public static double nextDouble (double d, boolean positive) {
/* filter out NaN's */
if (Double.isNaN(d)) {
return d;
}
/* zero's are also a special case */
if (d == 0.0) {
double smallestPositiveDouble = Double.longBitsToDouble(1L);
if (positive) {
return smallestPositiveDouble;
} else {
return -smallestPositiveDouble;
}
}
/* if entering here, d is a nonzero value */
/* hold all bits in a long for later use */
long bits = Double.doubleToLongBits(d);
/* strip off the sign bit */
long magnitude = bits & ~SIGN;
/* if next double away from zero, increase magnitude */
if ((bits > 0) == positive) {
if (magnitude != POSITIVEINFINITY) {
magnitude += 1;
}
}
/* else decrease magnitude */
else {
magnitude -= 1;
}
/* restore sign bit and return */
long signbit = bits & SIGN;
return Double.longBitsToDouble (magnitude | signbit);
}
private static double[] doubleArraySize(double[] array) {
int oldSize = array.length;
double[] newArray = new double[oldSize * 2];
System.arraycopy(array, 0, newArray, 0, oldSize);
return newArray;
}
private String[] doubleArraySize(String[] array) {
int oldSize = array.length;
String[] newArray = new String[oldSize * 2];
System.arraycopy(array, 0, newArray, 0, oldSize);
return newArray;
}
}
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