collator.java

java源代码 请看看啊 提点宝贵的意见

            try {
                result = new RuleBasedCollator( CollationRules.DEFAULTRULES );
            } catch (ParseException bar) {
                // do nothing
            }
        }
        // Now that RuleBasedCollator adds expansions for pre-composed characters
        // into their decomposed equivalents, the default collators don't need
        // to have decomposition turned on.  Laura, 5/5/98, bug 4114077
        result.setDecomposition(NO_DECOMPOSITION);
        
        cache.put(desiredLocale,result);
        return (Collator)result.clone();
    }

    /**
     * Compares the source string to the target string according to the
     * collation rules for this Collator.  Returns an integer less than,
     * equal to or greater than zero depending on whether the source String is
     * less than, equal to or greater than the target string.  See the Collator
     * class description for an example of use.
     * <p>
     * For a one time comparison, this method has the best performance. If a
     * given String will be involved in multiple comparisons, CollationKey.compareTo
     * has the best performance. See the Collator class description for an example
     * using CollationKeys.
     * @param source the source string.
     * @param target the target string.
     * @return Returns an integer value. Value is less than zero if source is less than
     * target, value is zero if source and target are equal, value is greater than zero
     * if source is greater than target.
     * @see java.text.CollationKey
     * @see java.text.Collator#getCollationKey
     */
    public abstract int compare(String source, String target);

    /**
     * Compares its two arguments for order.  Returns a negative integer,
     * zero, or a positive integer as the first argument is less than, equal
     * to, or greater than the second.
     * <p>
     * This implementation merely returns
     *  <code> compare((String)o1, (String)o2) </code>.
     * 
     * @return a negative integer, zero, or a positive integer as the
     *         first argument is less than, equal to, or greater than the
     *         second. 
     * @exception ClassCastException the arguments cannot be cast to Strings.
     * @see java.util.Comparator
     * @since   1.2
     */
    public int compare(Object o1, Object o2) {
    return compare((String)o1, (String)o2);
    }

    /**
     * Transforms the String into a series of bits that can be compared bitwise
     * to other CollationKeys. CollationKeys provide better performance than
     * Collator.compare when Strings are involved in multiple comparisons.
     * See the Collator class description for an example using CollationKeys.
     * @param source the string to be transformed into a collation key.
     * @return the CollationKey for the given String based on this Collator's collation
     * rules. If the source String is null, a null CollationKey is returned.
     * @see java.text.CollationKey
     * @see java.text.Collator#compare
     */
    public abstract CollationKey getCollationKey(String source);

    /**
     * Convenience method for comparing the equality of two strings based on
     * this Collator's collation rules.
     * @param source the source string to be compared with.
     * @param target the target string to be compared with.
     * @return true if the strings are equal according to the collation
     * rules.  false, otherwise.
     * @see java.text.Collator#compare
     */
    public boolean equals(String source, String target)
    {
        return (compare(source, target) == Collator.EQUAL);
    }

    /**
     * Returns this Collator's strength property.  The strength property determines
     * the minimum level of difference considered significant during comparison.
     * See the Collator class description for an example of use.
     * @return this Collator's current strength property.
     * @see java.text.Collator#setStrength
     * @see java.text.Collator#PRIMARY
     * @see java.text.Collator#SECONDARY
     * @see java.text.Collator#TERTIARY
     * @see java.text.Collator#IDENTICAL
     */
    public synchronized int getStrength()
    {
        return strength;
    }

    /**
     * Sets this Collator's strength property.  The strength property determines
     * the minimum level of difference considered significant during comparison.
     * See the Collator class description for an example of use.
     * @param newStrength  the new strength value.
     * @see java.text.Collator#getStrength
     * @see java.text.Collator#PRIMARY
     * @see java.text.Collator#SECONDARY
     * @see java.text.Collator#TERTIARY
     * @see java.text.Collator#IDENTICAL
     * @exception  IllegalArgumentException If the new strength value is not one of
     * PRIMARY, SECONDARY, TERTIARY or IDENTICAL.
     */
    public synchronized void setStrength(int newStrength) {
        if ((newStrength != PRIMARY) &&
            (newStrength != SECONDARY) &&
            (newStrength != TERTIARY) &&
            (newStrength != IDENTICAL))
            throw new IllegalArgumentException("Incorrect comparison level.");
        strength = newStrength;
    }

    /**
     * Get the decomposition mode of this Collator. Decomposition mode
     * determines how Unicode composed characters are handled. Adjusting
     * decomposition mode allows the user to select between faster and more
     * complete collation behavior.
     * <p>The three values for decomposition mode are:
     * <UL>
     * <LI>NO_DECOMPOSITION,
     * <LI>CANONICAL_DECOMPOSITION
     * <LI>FULL_DECOMPOSITION.
     * </UL>
     * See the documentation for these three constants for a description
     * of their meaning.
     * @return the decomposition mode
     * @see java.text.Collator#setDecomposition
     * @see java.text.Collator#NO_DECOMPOSITION
     * @see java.text.Collator#CANONICAL_DECOMPOSITION
     * @see java.text.Collator#FULL_DECOMPOSITION
     */
    public synchronized int getDecomposition()
    {
        return decmp;
    }
    /**
     * Set the decomposition mode of this Collator. See getDecomposition
     * for a description of decomposition mode.
     * @param decompositionMode  the new decomposition mode.
     * @see java.text.Collator#getDecomposition
     * @see java.text.Collator#NO_DECOMPOSITION
     * @see java.text.Collator#CANONICAL_DECOMPOSITION
     * @see java.text.Collator#FULL_DECOMPOSITION
     * @exception IllegalArgumentException If the given value is not a valid decomposition
     * mode.
     */
    public synchronized void setDecomposition(int decompositionMode) {
        if ((decompositionMode != NO_DECOMPOSITION) &&
            (decompositionMode != CANONICAL_DECOMPOSITION) &&
            (decompositionMode != FULL_DECOMPOSITION))
            throw new IllegalArgumentException("Wrong decomposition mode.");
        decmp = decompositionMode;
    }

    /**
     * Get the set of Locales for which Collators are installed.
     * @return the list of available locales which collators are installed.
     */
    public static synchronized Locale[] getAvailableLocales() {
        return LocaleData.getAvailableLocales("CollationElements");
    }

    /**
     * Overrides Cloneable
     */
    public Object clone()
    {
        try {
            return (Collator)super.clone();
        } catch (CloneNotSupportedException e) {
            throw new InternalError();
        }
    }

    /**
     * Compares the equality of two Collators.
     * @param that the Collator to be compared with this.
     * @return true if this Collator is the same as that Collator;
     * false otherwise.
     */
    public boolean equals(Object that)
    {
        if (this == that) return true;
        if (that == null) return false;
        if (getClass() != that.getClass()) return false;
        Collator other = (Collator) that;
        return ((strength == other.strength) &&
                (decmp == other.decmp));
    }

    /**
     * Generates the hash code for this Collator.
     */
    abstract public int hashCode();

    /**
     * Default constructor.  This constructor is
     * protected so subclasses can get access to it. Users typically create
     * a Collator sub-class by calling the factory method getInstance.
     * @see java.text.Collator#getInstance
     */
    protected Collator()
    {
        strength = TERTIARY;
        decmp = CANONICAL_DECOMPOSITION;
    }

    private int strength = 0;
    private int decmp = 0;
    private static SoftCache cache = new SoftCache();

    //
    // FIXME: These three constants should be removed.
    //
    /**
     * LESS is returned if source string is compared to be less than target
     * string in the compare() method.
     * @see java.text.Collator#compare
     */
    final static int LESS = -1;
    /**
     * EQUAL is returned if source string is compared to be equal to target
     * string in the compare() method.
     * @see java.text.Collator#compare
     */
    final static int EQUAL = 0;
    /**
     * GREATER is returned if source string is compared to be greater than
     * target string in the compare() method.
     * @see java.text.Collator#compare
     */
    final static int GREATER = 1;
 }