i will be selected for value X if
- * terminator[i] <= X < limit[i + 1]. If the value X is not
- * included in any range, then either the first or last format will be
- * used depending on whether the value X falls outside the range.
- * - * This sounds complicated, but that is because I did a poor job of - * explaining it. Consider the following example: - *
- *
- * terminators = { 1, ChoiceFormat.nextDouble(1) }
- * formats = { "file", "files" }
- *
- *
- * In this case if the actual number tested is one or less, then the word
- * "file" is used as the format value. If the number tested is greater than
- * one, then "files" is used. This allows plurals to be handled
- * gracefully. Note the use of the method nextDouble. This
- * method selects the next highest double number than its argument. This
- * effectively makes any double greater than 1.0 cause the "files" string
- * to be selected. (Note that all terminator values are specified as
- * doubles.
- *
- * Note that in order for this class to work properly, the range terminator
- * array must be sorted in ascending order and the format string array
- * must be the same length as the terminator array.
- *
- * @author Tom Tromey ChoiceFormat that
- * generates its range terminator and format string arrays from the
- * specified pattern. This pattern is of the form
- * "term#string|term#string...". For example "1#Sunday|2#Monday|#Tuesday".
- * This is the same pattern type used by the applyPattern
- * method.
- *
- * @param pattern The pattern of terminators and format strings.
- *
- * @exception IllegalArgumentException If the pattern is not valid
- */
- public ChoiceFormat (String newPattern)
- {
- super ();
- applyPattern (newPattern);
- }
-
- /**
- * This method initializes a new instance of ChoiceFormat that
- * will use the specified range terminators and format strings.
- *
- * @param choiceLimits The array of range terminators
- * @param choiceFormats The array of format strings
- */
- public ChoiceFormat (double[] choiceLimits, String[] choiceFormats)
- {
- super ();
- setChoices (choiceLimits, choiceFormats);
- }
-
- /**
- * This method tests this object for equality with the specified
- * object. This will be true if and only if:
- *
- *
- *
- * @param obj The object to test for equality against.
- *
- * @return null.
- * ChoiceFormat.
- * true if the specified object is equal to
- * this one, false otherwise.
- */
- public boolean equals (Object obj)
- {
- if (! (obj instanceof ChoiceFormat))
- return false;
- ChoiceFormat cf = (ChoiceFormat) obj;
- if (choiceLimits.length != cf.choiceLimits.length)
- return false;
- for (int i = choiceLimits.length - 1; i >= 0; --i)
- {
- if (choiceLimits[i] != cf.choiceLimits[i]
- || !choiceFormats[i].equals(cf.choiceFormats[i]))
- return false;
- }
- return true;
- }
-
- /**
- * This method appends the appropriate format string to the specified
- * StringBuffer based on the supplied long
- * argument.
- *
- * @param number The number used for determine (based on the range
- * terminators) which format string to append.
- * @param sb The StringBuffer to append the format string to.
- * @param status Unused.
- *
- * @return The StringBuffer with the format string appended.
- */
- public StringBuffer format (long num, StringBuffer appendBuf,
- FieldPosition pos)
- {
- return format ((double) num, appendBuf, pos);
- }
-
- /**
- * This method appends the appropriate format string to the specified
- * StringBuffer based on the supplied double
- * argument.
- *
- * @param number The number used for determine (based on the range
- * terminators) which format string to append.
- * @param sb The StringBuffer to append the format string to.
- * @param status Unused.
- *
- * @return The StringBuffer with the format string appended.
- */
- public StringBuffer format (double num, StringBuffer appendBuf,
- FieldPosition pos)
- {
- if (choiceLimits.length == 0)
- return appendBuf;
-
- int index = 0;
- if (! Double.isNaN(num) && num >= choiceLimits[0])
- {
- for (; index < choiceLimits.length - 1; ++index)
- {
- if (choiceLimits[index] <= num
- && index != choiceLimits.length - 2
- && num < choiceLimits[index + 1])
- break;
- }
- }
-
- return appendBuf.append(choiceFormats[index]);
- }
-
- /**
- * This method returns the list of format strings in use.
- *
- * @return The list of format objects.
- */
- public Object[] getFormats ()
- {
- return (Object[]) choiceFormats.clone();
- }
-
- /**
- * This method returns the list of range terminators in use.
- *
- * @return The list of range terminators.
- */
- public double[] getLimits ()
- {
- return (double[]) choiceLimits.clone();
- }
-
- /**
- * This method returns a hash value for this object
- *
- * @return A hash value for this object.
- */
- public int hashCode ()
- {
- int hash = 0;
- for (int i = 0; i < choiceLimits.length; ++i)
- {
- long v = Double.doubleToLongBits(choiceLimits[i]);
- hash ^= (v ^ (v >>> 32));
- hash ^= choiceFormats[i].hashCode();
- }
- return hash;
- }
-
- /**
- * This method returns the lowest possible double greater than the
- * specified double. If the specified double value is equal to
- * Double.NaN then that is the value returned.
- *
- * @param d The specified double
- *
- * @return The lowest double value greater than the specified double.
- */
- public static final double nextDouble (double d)
- {
- return nextDouble (d, true);
- }
-
- /**
- * This method returns a double that is either the next highest double
- * or next lowest double compared to the specified double depending on the
- * value of the passed boolean parameter. If the boolean parameter is
- * true, then the lowest possible double greater than the
- * specified double will be returned. Otherwise the highest possible
- * double less than the specified double will be returned.
- *
- * @param d The specified double
- * @param positive true to return the next highest
- * double, false otherwise.
- *
- * @return The next highest or lowest double value.
- */
- public static double nextDouble (double d, boolean next)
- {
- if (Double.isInfinite(d) || Double.isNaN(d))
- return d;
-
- long bits = Double.doubleToLongBits(d);
-
- long mantMask = (1L << mantissaBits) - 1;
- long mantissa = bits & mantMask;
-
- long expMask = (1L << exponentBits) - 1;
- long exponent = (bits >>> mantissaBits) & expMask;
-
- if (next ^ (bits < 0)) // Increment magnitude
- {
- if (mantissa == (1L << mantissaBits) - 1)
- {
- mantissa = 0L;
- exponent++;
-
- // Check for absolute overflow.
- if (exponent >= (1L << mantissaBits))
- return (bits > 0) ? Double.POSITIVE_INFINITY
- : Double.NEGATIVE_INFINITY;
- }
- else
- mantissa++;
- }
- else // Decrement magnitude
- {
- if (exponent == 0L && mantissa == 0L)
- {
- // The only case where there is a change of sign
- return next ? Double.MIN_VALUE : -Double.MIN_VALUE;
- }
- else
- {
- if (mantissa == 0L)
- {
- mantissa = (1L << mantissaBits) - 1;
- exponent--;
- }
- else
- mantissa--;
- }
- }
-
- long result = bits < 0 ? 1 : 0;
- result = (result << exponentBits) | exponent;
- result = (result << mantissaBits) | mantissa;
- return Double.longBitsToDouble(result);
- }
-
- /**
- * I'm not sure what this method is really supposed to do, as it is
- * not documented.
- */
- public Number parse (String sourceStr, ParsePosition pos)
- {
- int index = pos.getIndex();
- for (int i = 0; i < choiceLimits.length; ++i)
- {
- if (sourceStr.startsWith(choiceFormats[i], index))
- {
- pos.setIndex(index + choiceFormats[i].length());
- return new Double (choiceLimits[i]);
- }
- }
- pos.setErrorIndex(index);
- return new Double (Double.NaN);
- }
-
- /**
- * This method returns the highest possible double less than the
- * specified double. If the specified double value is equal to
- * Double.NaN then that is the value returned.
- *
- * @param d The specified double
- *
- * @return The highest double value less than the specified double.
- */
- public static final double previousDouble (double d)
- {
- return nextDouble (d, false);
- }
-
- /**
- * This method sets new range terminators and format strings for this
- * object.
- *
- * @param choiceLimits The new range terminators
- * @param choiceFormats The new choice formats
- */
- public void setChoices (double[] choiceLimits, String[] choiceFormats)
- {
- if (choiceLimits == null || choiceFormats == null)
- throw new NullPointerException ();
- if (choiceLimits.length != choiceFormats.length)
- throw new IllegalArgumentException ();
- this.choiceFormats = (String[]) choiceFormats.clone();
- this.choiceLimits = (double[]) choiceLimits.clone();
- }
-
- private final void quoteString (StringBuffer dest, String text)
- {
- int max = text.length();
- for (int i = 0; i < max; ++i)
- {
- char c = text.charAt(i);
- if (c == '\'')
- {
- dest.append(c);
- dest.append(c);
- }
- else if (c == '#' || c == '|' || c == '\u2064' || c == '<')
- {
- dest.append('\'');
- dest.append(c);
- dest.append('\'');
- }
- else
- dest.append(c);
- }
- }
-
- /**
- * This method returns the range terminator list and format string list
- * as a String suitable for using with the
- * applyPattern method.
- *
- * @return A pattern string for this object
- */
- public String toPattern ()
- {
- StringBuffer result = new StringBuffer ();
- for (int i = 0; i < choiceLimits.length; ++i)
- {
- result.append(choiceLimits[i]);
- result.append('#');
- quoteString (result, choiceFormats[i]);
- }
- return result.toString();
- }
-
- /**
- * This is the list of format strings. Note that this variable is
- * specified by the serialization spec of this class.
- */
- private String[] choiceFormats;
-
- /**
- * This is the list of range terminator values. Note that this variable is
- * specified by the serialization spec of this class.
- */
- private double[] choiceLimits;
-
- // Number of mantissa bits in double.
- private static final int mantissaBits = 52;
- // Number of exponent bits in a double.
- private static final int exponentBits = 11;
-
- private static final long serialVersionUID = 1795184449645032964L;
-}