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 *
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/*
 * (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.text.Normalizer;
import java.util.Vector;
import java.util.Locale;

/**
 * The <code>RuleBasedCollator</code> class is a concrete subclass of
 * <code>Collator</code> that provides a simple, data-driven, table
 * collator. With this class you can create a customized table-based
 * <code>Collator</code>. <code>RuleBasedCollator</code> maps
 * characters to sort keys.
 *
 * <p>
 * <code>RuleBasedCollator</code> has the following restrictions
 * for efficiency (other subclasses may be used for more complex languages) :
 * <ol>
 * <li>If a special collation rule controlled by a &lt;modifier&gt; is
 specified it applies to the whole collator object.
 * <li>All non-mentioned characters are at the end of the
 * collation order.
 * </ol>
 *
 * <p>
 * The collation table is composed of a list of collation rules, where each
 * rule is of one of three forms:
 * <pre>
 * &lt;modifier&gt;
 * &lt;relation&gt; &lt;text-argument&gt;
 * &lt;reset&gt; &lt;text-argument&gt;
 * </pre>
 * The definitions of the rule elements is as follows:
 * <UL>
 * <LI><strong>Text-Argument</strong>: A text-argument is any sequence of
 * characters, excluding special characters (that is, common
 * whitespace characters [0009-000D, 0020] and rule syntax characters
 * [0021-002F, 003A-0040, 005B-0060, 007B-007E]). If those
 * characters are desired, you can put them in single quotes
 * (e.g. ampersand =&gt; '&amp;'). Note that unquoted white space characters
 * are ignored; e.g. <code>b c</code> is treated as <code>bc</code>.
 * <LI><strong>Modifier</strong>: There are currently two modifiers that
 * turn on special collation rules.
 * <UL>
 * <LI>'@' : Turns on backwards sorting of accents (secondary
 * differences), as in French.
 * <LI>'!' : Turns on Thai/Lao vowel-consonant swapping. If this
 * rule is in force when a Thai vowel of the range
 * &#92;U0E40-&#92;U0E44 precedes a Thai consonant of the range
 * &#92;U0E01-&#92;U0E2E OR a Lao vowel of the range &#92;U0EC0-&#92;U0EC4
 * precedes a Lao consonant of the range &#92;U0E81-&#92;U0EAE then
 * the vowel is placed after the consonant for collation
 * purposes.
 * </UL>
 * <p>'@' : Indicates that accents are sorted backwards, as in French.
 * <LI><strong>Relation</strong>: The relations are the following:
 * <UL>
 * <LI>'&lt;' : Greater, as a letter difference (primary)
 * <LI>';' : Greater, as an accent difference (secondary)
 * <LI>',' : Greater, as a case difference (tertiary)
 * <LI>'=' : Equal
 * </UL>
 * <LI><strong>Reset</strong>: There is a single reset
 * which is used primarily for contractions and expansions, but which
 * can also be used to add a modification at the end of a set of rules.
 * <p>'&amp;' : Indicates that the next rule follows the position to where
 * the reset text-argument would be sorted.
 * </UL>
 *
 * <p>
 * This sounds more complicated than it is in practice. For example, the
 * following are equivalent ways of expressing the same thing:
 * <blockquote>
 * <pre>
 * a &lt; b &lt; c
 * a &lt; b &amp; b &lt; c
 * a &lt; c &amp; a &lt; b
 * </pre>
 * </blockquote>
 * Notice that the order is important, as the subsequent item goes immediately
 * after the text-argument. The following are not equivalent:
 * <blockquote>
 * <pre>
 * a &lt; b &amp; a &lt; c
 * a &lt; c &amp; a &lt; b
 * </pre>
 * </blockquote>
 * Either the text-argument must already be present in the sequence, or some
 * initial substring of the text-argument must be present. (e.g. "a &lt; b &amp; ae &lt;
 * e" is valid since "a" is present in the sequence before "ae" is reset). In
 * this latter case, "ae" is not entered and treated as a single character;
 * instead, "e" is sorted as if it were expanded to two characters: "a"
 * followed by an "e". This difference appears in natural languages: in
 * traditional Spanish "ch" is treated as though it contracts to a single
 * character (expressed as "c &lt; ch &lt; d"), while in traditional German
 * a-umlaut is treated as though it expanded to two characters
 * (expressed as "a,A &lt; b,B ... &amp;ae;&#92;u00e3&amp;AE;&#92;u00c3").
 * [&#92;u00e3 and &#92;u00c3 are, of course, the escape sequences for a-umlaut.]
 * <p>
 * <strong>Ignorable Characters</strong>
 * <p>
 * For ignorable characters, the first rule must start with a relation (the
 * examples we have used above are really fragments; "a &lt; b" really should be
 * "&lt; a &lt; b"). If, however, the first relation is not "&lt;", then all the all
 * text-arguments up to the first "&lt;" are ignorable. For example, ", - &lt; a &lt; b"
 * makes "-" an ignorable character, as we saw earlier in the word
 * "black-birds". In the samples for different languages, you see that most
 * accents are ignorable.
 *
 * <p><strong>Normalization and Accents</strong>
 * <p>
 * <code>RuleBasedCollator</code> automatically processes its rule table to
 * include both pre-composed and combining-character versions of
 * accented characters. Even if the provided rule string contains only
 * base characters and separate combining accent characters, the pre-composed
 * accented characters matching all canonical combinations of characters from
 * the rule string will be entered in the table.
 * <p>
 * This allows you to use a RuleBasedCollator to compare accented strings
 * even when the collator is set to NO_DECOMPOSITION. There are two caveats,
 * however. First, if the strings to be collated contain combining
 * sequences that may not be in canonical order, you should set the collator to
 * CANONICAL_DECOMPOSITION or FULL_DECOMPOSITION to enable sorting of
 * combining sequences. Second, if the strings contain characters with
 * compatibility decompositions (such as full-width and half-width forms),
 * you must use FULL_DECOMPOSITION, since the rule tables only include
 * canonical mappings.
 *
 * <p><strong>Errors</strong>
 * <p>
 * The following are errors:
 * <UL>
 * <LI>A text-argument contains unquoted punctuation symbols
 * (e.g. "a &lt; b-c &lt; d").
 * <LI>A relation or reset character not followed by a text-argument
 * (e.g. "a &lt; ,b").
 * <LI>A reset where the text-argument (or an initial substring of the
 * text-argument) is not already in the sequence.
 * (e.g. "a &lt; b &amp; e &lt; f")
 * </UL>
 * If you produce one of these errors, a <code>RuleBasedCollator</code> throws
 * a <code>ParseException</code>.
 *
 * <p><strong>Examples</strong>
 * <p>Simple: "&lt; a &lt; b &lt; c &lt; d"
 * <p>Norwegian: "&lt; a, A &lt; b, B &lt; c, C &lt; d, D &lt; e, E &lt; f, F
 * &lt; g, G &lt; h, H &lt; i, I &lt; j, J &lt; k, K &lt; l, L
 * &lt; m, M &lt; n, N &lt; o, O &lt; p, P &lt; q, Q &lt; r, R
 * &lt; s, S &lt; t, T &lt; u, U &lt; v, V &lt; w, W &lt; x, X
 * &lt; y, Y &lt; z, Z
 * &lt; &#92;u00E6, &#92;u00C6
 * &lt; &#92;u00F8, &#92;u00D8
 * &lt; &#92;u00E5 = a&#92;u030A, &#92;u00C5 = A&#92;u030A;
 * aa, AA"
 *
 * <p>
 * To create a <code>RuleBasedCollator</code> object with specialized
 * rules tailored to your needs, you construct the <code>RuleBasedCollator</code>
 * with the rules contained in a <code>String</code> object. For example:
 * <blockquote>
 * <pre>
 * String simple = "&lt; a&lt; b&lt; c&lt; d";
 * RuleBasedCollator mySimple = new RuleBasedCollator(simple);
 * </pre>
 * </blockquote>
 * Or:
 * <blockquote>
 * <pre>
 * String Norwegian = "&lt; a, A &lt; b, B &lt; c, C &lt; d, D &lt; e, E &lt; f, F &lt; g, G &lt; h, H &lt; i, I" +
 * "&lt; j, J &lt; k, K &lt; l, L &lt; m, M &lt; n, N &lt; o, O &lt; p, P &lt; q, Q &lt; r, R" +
 * "&lt; s, S &lt; t, T &lt; u, U &lt; v, V &lt; w, W &lt; x, X &lt; y, Y &lt; z, Z" +
 * "&lt; &#92;u00E6, &#92;u00C6" + // Latin letter ae &amp; AE
 * "&lt; &#92;u00F8, &#92;u00D8" + // Latin letter o &amp; O with stroke
 * "&lt; &#92;u00E5 = a&#92;u030A," + // Latin letter a with ring above
 * " &#92;u00C5 = A&#92;u030A;" + // Latin letter A with ring above
 * " aa, AA";
 * RuleBasedCollator myNorwegian = new RuleBasedCollator(Norwegian);
 * </pre>
 * </blockquote>
 *
 * <p>
 * A new collation rules string can be created by concatenating rules
 * strings. For example, the rules returned by {@link #getRules()} could
 * be concatenated to combine multiple <code>RuleBasedCollator</code>s.
 *
 * <p>
 * The following example demonstrates how to change the order of
 * non-spacing accents,
 * <blockquote>
 * <pre>
 * // old rule
 * String oldRules = "=&#92;u0301;&#92;u0300;&#92;u0302;&#92;u0308" // main accents
 * + ";&#92;u0327;&#92;u0303;&#92;u0304;&#92;u0305" // main accents
 * + ";&#92;u0306;&#92;u0307;&#92;u0309;&#92;u030A" // main accents
 * + ";&#92;u030B;&#92;u030C;&#92;u030D;&#92;u030E" // main accents
 * + ";&#92;u030F;&#92;u0310;&#92;u0311;&#92;u0312" // main accents
 * + "&lt; a , A ; ae, AE ; &#92;u00e6 , &#92;u00c6"
 * + "&lt; b , B &lt; c, C &lt; e, E &amp; C &lt; d, D";
 * // change the order of accent characters
 * String addOn = "&amp; &#92;u0300 ; &#92;u0308 ; &#92;u0302";
 * RuleBasedCollator myCollator = new RuleBasedCollator(oldRules + addOn);
 * </pre>
 * </blockquote>
 *
 * @see Collator
 * @see CollationElementIterator
 * @author Helena Shih, Laura Werner, Richard Gillam
 * @since 1.1
 */
public class RuleBasedCollator extends Collator{
 // IMPLEMENTATION NOTES: The implementation of the collation algorithm is
 // divided across three classes: RuleBasedCollator, RBCollationTables, and
 // CollationElementIterator. RuleBasedCollator contains the collator's
 // transient state and includes the code that uses the other classes to
 // implement comparison and sort-key building. RuleBasedCollator also
 // contains the logic to handle French secondary accent sorting.
 // A RuleBasedCollator has two CollationElementIterators. State doesn't
 // need to be preserved in these objects between calls to compare() or
 // getCollationKey(), but the objects persist anyway to avoid wasting extra
 // creation time. compare() and getCollationKey() are synchronized to ensure
 // thread safety with this scheme. The CollationElementIterator is responsible
 // for generating collation elements from strings and returning one element at
 // a time (sometimes there's a one-to-many or many-to-one mapping between
 // characters and collation elements-- this class handles that).
 // CollationElementIterator depends on RBCollationTables, which contains the
 // collator's static state. RBCollationTables contains the actual data
 // tables specifying the collation order of characters for a particular locale
 // or use. It also contains the base logic that CollationElementIterator
 // uses to map from characters to collation elements. A single RBCollationTables
 // object is shared among all RuleBasedCollators for the same locale, and
 // thus by all the CollationElementIterators they create.

 /**
 * RuleBasedCollator constructor. This takes the table rules and builds
 * a collation table out of them. Please see RuleBasedCollator class
 * description for more details on the collation rule syntax.
 * @see java.util.Locale
 * @param rules the collation rules to build the collation table from.
 * @exception ParseException A format exception
 * will be thrown if the build process of the rules fails. For
 * example, build rule "a &lt; ? &lt; d" will cause the constructor to
 * throw the ParseException because the '?' is not quoted.
 */
 public RuleBasedCollator(String rules) throws ParseException {
 this(rules, Collator.CANONICAL_DECOMPOSITION);
 }

 /**
 * RuleBasedCollator constructor. This takes the table rules and builds
 * a collation table out of them. Please see RuleBasedCollator class
 * description for more details on the collation rule syntax.
 * @see java.util.Locale
 * @param rules the collation rules to build the collation table from.
 * @param decomp the decomposition strength used to build the
 * collation table and to perform comparisons.
 * @exception ParseException A format exception
 * will be thrown if the build process of the rules fails. For
 * example, build rule "a < ? < d" will cause the constructor to
 * throw the ParseException because the '?' is not quoted.
 */
 RuleBasedCollator(String rules, int decomp) throws ParseException {
 setStrength(Collator.TERTIARY);
 setDecomposition(decomp);
 tables = new RBCollationTables(rules, decomp);
 }

 /**
 * "Copy constructor." Used in clone() for performance.
 */
 private RuleBasedCollator(RuleBasedCollator that) {
 setStrength(that.getStrength());
 setDecomposition(that.getDecomposition());
 tables = that.tables;
 }

 /**
 * Gets the table-based rules for the collation object.
 * @return returns the collation rules that the table collation object
 * was created from.
 */
 public String getRules()
 {
 return tables.getRules();
 }

 /**
 * Returns a CollationElementIterator for the given String.
 *
 * @param source the string to be collated
 * @return a {@code CollationElementIterator} object
 * @see java.text.CollationElementIterator
 */
 public CollationElementIterator getCollationElementIterator(String source) {
 return new CollationElementIterator( source, this );
 }

 /**
 * Returns a CollationElementIterator for the given CharacterIterator.
 *
 * @param source the character iterator to be collated
 * @return a {@code CollationElementIterator} object
 * @see java.text.CollationElementIterator
 * @since 1.2
 */
 public CollationElementIterator getCollationElementIterator(
 CharacterIterator source) {
 return new CollationElementIterator( source, this );
 }

 /**
 * Compares the character data stored in two different strings based on the
 * collation rules. Returns information about whether a string is less
 * than, greater than or equal to another string in a language.
 * This can be overriden in a subclass.
 *
 * @exception NullPointerException if <code>source</code> or <code>target</code> is null.
 */
 public synchronized int compare(String source, String target)
 {
 if (source == null || target == null) {
 throw new NullPointerException();
 }

 // The basic algorithm here is that we use CollationElementIterators
 // to step through both the source and target strings. We compare each
 // collation element in the source string against the corresponding one
 // in the target, checking for differences.
 //
 // If a difference is found, we set <result> to LESS or GREATER to
 // indicate whether the source string is less or greater than the target.
 //
 // However, it's not that simple. If we find a tertiary difference
 // (e.g. 'A' vs. 'a') near the beginning of a string, it can be
 // overridden by a primary difference (e.g. "A" vs. "B") later in
 // the string. For example, "AA" < "aB", even though 'A' > 'a'.
 //
 // To keep track of this, we use strengthResult to keep track of the
 // strength of the most significant difference that has been found
 // so far. When we find a difference whose strength is greater than
 // strengthResult, it overrides the last difference (if any) that
 // was found.

 int result = Collator.EQUAL;

 if (sourceCursor == null) {
 sourceCursor = getCollationElementIterator(source);
 } else {
 sourceCursor.setText(source);
 }
 if (targetCursor == null) {
 targetCursor = getCollationElementIterator(target);
 } else {
 targetCursor.setText(target);
 }

 int sOrder = 0, tOrder = 0;

 boolean initialCheckSecTer = getStrength() >= Collator.SECONDARY;
 boolean checkSecTer = initialCheckSecTer;
 boolean checkTertiary = getStrength() >= Collator.TERTIARY;

 boolean gets = true, gett = true;

 while(true) {
 // Get the next collation element in each of the strings, unless
 // we've been requested to skip it.
 if (gets) sOrder = sourceCursor.next(); else gets = true;
 if (gett) tOrder = targetCursor.next(); else gett = true;

 // If we've hit the end of one of the strings, jump out of the loop
 if ((sOrder == CollationElementIterator.NULLORDER)||
 (tOrder == CollationElementIterator.NULLORDER))
 break;

 int pSOrder = CollationElementIterator.primaryOrder(sOrder);
 int pTOrder = CollationElementIterator.primaryOrder(tOrder);

 // If there's no difference at this position, we can skip it
 if (sOrder == tOrder) {
 if (tables.isFrenchSec() && pSOrder != 0) {
 if (!checkSecTer) {
 // in french, a secondary difference more to the right is stronger,
 // so accents have to be checked with each base element
 checkSecTer = initialCheckSecTer;
 // but tertiary differences are less important than the first
 // secondary difference, so checking tertiary remains disabled
 checkTertiary = false;
 }
 }
 continue;
 }

 // Compare primary differences first.
 if ( pSOrder != pTOrder )
 {
 if (sOrder == 0) {
 // The entire source element is ignorable.
 // Skip to the next source element, but don't fetch another target element.
 gett = false;
 continue;
 }
 if (tOrder == 0) {
 gets = false;
 continue;
 }

 // The source and target elements aren't ignorable, but it's still possible
 // for the primary component of one of the elements to be ignorable....

 if (pSOrder == 0) // primary order in source is ignorable
 {
 // The source's primary is ignorable, but the target's isn't. We treat ignorables
 // as a secondary difference, so remember that we found one.
 if (checkSecTer) {
 result = Collator.GREATER; // (strength is SECONDARY)
 checkSecTer = false;
 }
 // Skip to the next source element, but don't fetch another target element.
 gett = false;
 }
 else if (pTOrder == 0)
 {
 // record differences - see the comment above.
 if (checkSecTer) {
 result = Collator.LESS; // (strength is SECONDARY)
 checkSecTer = false;
 }
 // Skip to the next source element, but don't fetch another target element.
 gets = false;
 } else {
 // Neither of the orders is ignorable, and we already know that the primary
 // orders are different because of the (pSOrder != pTOrder) test above.
 // Record the difference and stop the comparison.
 if (pSOrder < pTOrder) {
 return Collator.LESS; // (strength is PRIMARY)
 } else {
 return Collator.GREATER; // (strength is PRIMARY)
 }
 }
 } else { // else of if ( pSOrder != pTOrder )
 // primary order is the same, but complete order is different. So there
 // are no base elements at this point, only ignorables (Since the strings are
 // normalized)

 if (checkSecTer) {
 // a secondary or tertiary difference may still matter
 short secSOrder = CollationElementIterator.secondaryOrder(sOrder);
 short secTOrder = CollationElementIterator.secondaryOrder(tOrder);
 if (secSOrder != secTOrder) {
 // there is a secondary difference
 result = (secSOrder < secTOrder) ? Collator.LESS : Collator.GREATER;
 // (strength is SECONDARY)
 checkSecTer = false;
 // (even in french, only the first secondary difference within
 // a base character matters)
 } else {
 if (checkTertiary) {
 // a tertiary difference may still matter
 short terSOrder = CollationElementIterator.tertiaryOrder(sOrder);
 short terTOrder = CollationElementIterator.tertiaryOrder(tOrder);
 if (terSOrder != terTOrder) {
 // there is a tertiary difference
 result = (terSOrder < terTOrder) ? Collator.LESS : Collator.GREATER;
 // (strength is TERTIARY)
 checkTertiary = false;
 }
 }
 }
 } // if (checkSecTer)

 } // if ( pSOrder != pTOrder )
 } // while()

 if (sOrder != CollationElementIterator.NULLORDER) {
 // (tOrder must be CollationElementIterator::NULLORDER,
 // since this point is only reached when sOrder or tOrder is NULLORDER.)
 // The source string has more elements, but the target string hasn't.
 do {
 if (CollationElementIterator.primaryOrder(sOrder) != 0) {
 // We found an additional non-ignorable base character in the source string.
 // This is a primary difference, so the source is greater
 return Collator.GREATER; // (strength is PRIMARY)
 }
 else if (CollationElementIterator.secondaryOrder(sOrder) != 0) {
 // Additional secondary elements mean the source string is greater
 if (checkSecTer) {
 result = Collator.GREATER; // (strength is SECONDARY)
 checkSecTer = false;
 }
 }
 } while ((sOrder = sourceCursor.next()) != CollationElementIterator.NULLORDER);
 }
 else if (tOrder != CollationElementIterator.NULLORDER) {
 // The target string has more elements, but the source string hasn't.
 do {
 if (CollationElementIterator.primaryOrder(tOrder) != 0)
 // We found an additional non-ignorable base character in the target string.
 // This is a primary difference, so the source is less
 return Collator.LESS; // (strength is PRIMARY)
 else if (CollationElementIterator.secondaryOrder(tOrder) != 0) {
 // Additional secondary elements in the target mean the source string is less
 if (checkSecTer) {
 result = Collator.LESS; // (strength is SECONDARY)
 checkSecTer = false;
 }
 }
 } while ((tOrder = targetCursor.next()) != CollationElementIterator.NULLORDER);
 }

 // For IDENTICAL comparisons, we use a bitwise character comparison
 // as a tiebreaker if all else is equal
 if (result == 0 && getStrength() == IDENTICAL) {
 int mode = getDecomposition();
 Normalizer.Form form;
 if (mode == CANONICAL_DECOMPOSITION) {
 form = Normalizer.Form.NFD;
 } else if (mode == FULL_DECOMPOSITION) {
 form = Normalizer.Form.NFKD;
 } else {
 return source.compareTo(target);
 }

 String sourceDecomposition = Normalizer.normalize(source, form);
 String targetDecomposition = Normalizer.normalize(target, form);
 return sourceDecomposition.compareTo(targetDecomposition);
 }
 return result;
 }

 /**
 * Transforms the string into a series of characters that can be compared
 * with CollationKey.compareTo. This overrides java.text.Collator.getCollationKey.
 * It can be overriden in a subclass.
 */
 public synchronized CollationKey getCollationKey(String source)
 {
 //
 // The basic algorithm here is to find all of the collation elements for each
 // character in the source string, convert them to a char representation,
 // and put them into the collation key. But it's trickier than that.
 // Each collation element in a string has three components: primary (A vs B),
 // secondary (A vs A-acute), and tertiary (A' vs a); and a primary difference
 // at the end of a string takes precedence over a secondary or tertiary
 // difference earlier in the string.
 //
 // To account for this, we put all of the primary orders at the beginning of the
 // string, followed by the secondary and tertiary orders, separated by nulls.
 //
 // Here's a hypothetical example, with the collation element represented as
 // a three-digit number, one digit for primary, one for secondary, etc.
 //
 // String: A a B \u00e9 <--(e-acute)
 // Collation Elements: 101 100 201 510
 //
 // Collation Key: 1125<null>0001<null>1010
 //
 // To make things even trickier, secondary differences (accent marks) are compared
 // starting at the *end* of the string in languages with French secondary ordering.
 // But when comparing the accent marks on a single base character, they are compared
 // from the beginning. To handle this, we reverse all of the accents that belong
 // to each base character, then we reverse the entire string of secondary orderings
 // at the end. Taking the same example above, a French collator might return
 // this instead:
 //
 // Collation Key: 1125<null>1000<null>1010
 //
 if (source == null)
 return null;

 if (primResult == null) {
 primResult = new StringBuffer();
 secResult = new StringBuffer();
 terResult = new StringBuffer();
 } else {
 primResult.setLength(0);
 secResult.setLength(0);
 terResult.setLength(0);
 }
 int order = 0;
 boolean compareSec = (getStrength() >= Collator.SECONDARY);
 boolean compareTer = (getStrength() >= Collator.TERTIARY);
 int secOrder = CollationElementIterator.NULLORDER;
 int terOrder = CollationElementIterator.NULLORDER;
 int preSecIgnore = 0;

 if (sourceCursor == null) {
 sourceCursor = getCollationElementIterator(source);
 } else {
 sourceCursor.setText(source);
 }

 // walk through each character
 while ((order = sourceCursor.next()) !=
 CollationElementIterator.NULLORDER)
 {
 secOrder = CollationElementIterator.secondaryOrder(order);
 terOrder = CollationElementIterator.tertiaryOrder(order);
 if (!CollationElementIterator.isIgnorable(order))
 {
 primResult.append((char) (CollationElementIterator.primaryOrder(order)
 + COLLATIONKEYOFFSET));

 if (compareSec) {
 //
 // accumulate all of the ignorable/secondary characters attached
 // to a given base character
 //
 if (tables.isFrenchSec() && preSecIgnore < secResult.length()) {
 //
 // We're doing reversed secondary ordering and we've hit a base
 // (non-ignorable) character. Reverse any secondary orderings
 // that applied to the last base character. (see block comment above.)
 //
 RBCollationTables.reverse(secResult, preSecIgnore, secResult.length());
 }
 // Remember where we are in the secondary orderings - this is how far
 // back to go if we need to reverse them later.
 secResult.append((char)(secOrder+ COLLATIONKEYOFFSET));
 preSecIgnore = secResult.length();
 }
 if (compareTer) {
 terResult.append((char)(terOrder+ COLLATIONKEYOFFSET));
 }
 }
 else
 {
 if (compareSec && secOrder != 0)
 secResult.append((char)
 (secOrder + tables.getMaxSecOrder() + COLLATIONKEYOFFSET));
 if (compareTer && terOrder != 0)
 terResult.append((char)
 (terOrder + tables.getMaxTerOrder() + COLLATIONKEYOFFSET));
 }
 }
 if (tables.isFrenchSec())
 {
 if (preSecIgnore < secResult.length()) {
 // If we've accumulated any secondary characters after the last base character,
 // reverse them.
 RBCollationTables.reverse(secResult, preSecIgnore, secResult.length());
 }
 // And now reverse the entire secResult to get French secondary ordering.
 RBCollationTables.reverse(secResult, 0, secResult.length());
 }
 primResult.append((char)0);
 secResult.append((char)0);
 secResult.append(terResult.toString());
 primResult.append(secResult.toString());

 if (getStrength() == IDENTICAL) {
 primResult.append((char)0);
 int mode = getDecomposition();
 if (mode == CANONICAL_DECOMPOSITION) {
 primResult.append(Normalizer.normalize(source, Normalizer.Form.NFD));
 } else if (mode == FULL_DECOMPOSITION) {
 primResult.append(Normalizer.normalize(source, Normalizer.Form.NFKD));
 } else {
 primResult.append(source);
 }
 }
 return new RuleBasedCollationKey(source, primResult.toString());
 }

 /**
 * Standard override; no change in semantics.
 */
 public Object clone() {
 // if we know we're not actually a subclass of RuleBasedCollator
 // (this class really should have been made final), bypass
 // Object.clone() and use our "copy constructor". This is faster.
 if (getClass() == RuleBasedCollator.class) {
 return new RuleBasedCollator(this);
 }
 else {
 RuleBasedCollator result = (RuleBasedCollator) super.clone();
 result.primResult = null;
 result.secResult = null;
 result.terResult = null;
 result.sourceCursor = null;
 result.targetCursor = null;
 return result;
 }
 }

 /**
 * Compares the equality of two collation objects.
 * @param obj the table-based collation object to be compared with this.
 * @return true if the current table-based collation object is the same
 * as the table-based collation object obj; false otherwise.
 */
 public boolean equals(Object obj) {
 if (obj == null) return false;
 if (!super.equals(obj)) return false; // super does class check
 RuleBasedCollator other = (RuleBasedCollator) obj;
 // all other non-transient information is also contained in rules.
 return (getRules().equals(other.getRules()));
 }

 /**
 * Generates the hash code for the table-based collation object
 */
 public int hashCode() {
 return getRules().hashCode();
 }

 /**
 * Allows CollationElementIterator access to the tables object
 */
 RBCollationTables getTables() {
 return tables;
 }

 // ==============================================================
 // private
 // ==============================================================

 static final int CHARINDEX = 0x70000000; // need look up in .commit()
 static final int EXPANDCHARINDEX = 0x7E000000; // Expand index follows
 static final int CONTRACTCHARINDEX = 0x7F000000; // contract indexes follow
 static final int UNMAPPED = 0xFFFFFFFF;

 private static final int COLLATIONKEYOFFSET = 1;

 private RBCollationTables tables = null;

 // Internal objects that are cached across calls so that they don't have to
 // be created/destroyed on every call to compare() and getCollationKey()
 private StringBuffer primResult = null;
 private StringBuffer secResult = null;
 private StringBuffer terResult = null;
 private CollationElementIterator sourceCursor = null;
 private CollationElementIterator targetCursor = null;
}