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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 libcore.icu.CollationKeyICU; |
| |
| /** |
| * 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 <modifier> 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> |
| * <modifier> |
| * <relation> <text-argument> |
| * <reset> <text-argument> |
| * </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 => '&'). 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 |
| * \U0E40-\U0E44 precedes a Thai consonant of the range |
| * \U0E01-\U0E2E OR a Lao vowel of the range \U0EC0-\U0EC4 |
| * precedes a Lao consonant of the range \U0E81-\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>'<' : 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>'&' : 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 < b < c |
| * a < b & b < c |
| * a < c & a < 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 < b & a < c |
| * a < c & a < 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 < b & ae < |
| * 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 < ch < d"), while in traditional German |
| * a-umlaut is treated as though it expanded to two characters |
| * (expressed as "a,A < b,B ... &ae;\u00e3&AE;\u00c3"). |
| * [\u00e3 and \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 < b" really should be |
| * "< a < b"). If, however, the first relation is not "<", then all the all |
| * text-arguments up to the first "<" are ignorable. For example, ", - < a < 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 < b-c < d"). |
| * <LI>A relation or reset character not followed by a text-argument |
| * (e.g. "a < ,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 < b & e < f") |
| * </UL> |
| * If you produce one of these errors, a <code>RuleBasedCollator</code> throws |
| * a <code>ParseException</code>. |
| * |
| * <p><strong>Examples</strong> |
| * <p>Simple: "< a < b < c < d" |
| * <p>Norwegian: "< a, A < b, B < c, C < d, D < e, E < f, F |
| * < g, G < h, H < i, I < j, J < k, K < l, L |
| * < m, M < n, N < o, O < p, P < q, Q < r, R |
| * < s, S < t, T < u, U < v, V < w, W < x, X |
| * < y, Y < z, Z |
| * < \u00E6, \u00C6 |
| * < \u00F8, \u00D8 |
| * < \u00E5 = a\u030A, \u00C5 = A\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 = "< a< b< c< d"; |
| * RuleBasedCollator mySimple = new RuleBasedCollator(simple); |
| * </pre> |
| * </blockquote> |
| * Or: |
| * <blockquote> |
| * <pre> |
| * String Norwegian = "< a, A < b, B < c, C < d, D < e, E < f, F < g, G < h, H < i, I" + |
| * "< j, J < k, K < l, L < m, M < n, N < o, O < p, P < q, Q < r, R" + |
| * "< s, S < t, T < u, U < v, V < w, W < x, X < y, Y < z, Z" + |
| * "< \u00E6, \u00C6" + // Latin letter ae & AE |
| * "< \u00F8, \u00D8" + // Latin letter o & O with stroke |
| * "< \u00E5 = a\u030A," + // Latin letter a with ring above |
| * " \u00C5 = A\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 = "=\u0301;\u0300;\u0302;\u0308" // main accents |
| * + ";\u0327;\u0303;\u0304;\u0305" // main accents |
| * + ";\u0306;\u0307;\u0309;\u030A" // main accents |
| * + ";\u030B;\u030C;\u030D;\u030E" // main accents |
| * + ";\u030F;\u0310;\u0311;\u0312" // main accents |
| * + "< a , A ; ae, AE ; \u00e6 , \u00c6" |
| * + "< b , B < c, C < e, E & C < d, D"; |
| * // change the order of accent characters |
| * String addOn = "& \u0300 ; \u0308 ; \u0302"; |
| * RuleBasedCollator myCollator = new RuleBasedCollator(oldRules + addOn); |
| * </pre> |
| * </blockquote> |
| * |
| * @see Collator |
| * @see CollationElementIterator |
| * @author Helena Shih, Laura Werner, Richard Gillam |
| */ |
| public class RuleBasedCollator extends Collator{ |
| // Android-added: protected constructor taking an ICU RuleBasedCollator. |
| RuleBasedCollator(android.icu.text.RuleBasedCollator wrapper) { |
| super(wrapper); |
| } |
| |
| // 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 < ? < d" will cause the constructor to |
| * throw the ParseException because the '?' is not quoted. |
| */ |
| public RuleBasedCollator(String rules) throws ParseException { |
| // BEGIN Android-changed: Switched to ICU. |
| if (rules == null) { |
| throw new NullPointerException("rules == null"); |
| } |
| try { |
| icuColl = new android.icu.text.RuleBasedCollator(rules); |
| } catch (Exception e) { |
| if (e instanceof ParseException) { |
| throw (ParseException) e; |
| } |
| /* |
| * -1 means it's not a ParseException. Maybe IOException thrown when |
| * an error occurred while reading internal data. |
| */ |
| throw new ParseException(e.getMessage(), -1); |
| } |
| // BEGIN Android-changed: Switched to ICU. |
| } |
| |
| // Android-removed: (String rules, int decomp) constructor and copy constructor. |
| |
| // Android-changed: document that getRules() won't return rules in common case. |
| /** |
| * Gets the table-based rules for the collation object. |
| * |
| * <p>On Android, the returned string will be empty unless this instance was |
| * constructed using {@link #RuleBasedCollator(String)}. |
| * |
| * @return returns the collation rules that the table collation object |
| * was created from. |
| */ |
| public String getRules() |
| { |
| // Android-changed: Switched to ICU. |
| return collAsICU().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) { |
| // Android-changed: Switch to ICU and check for null value. |
| if (source == null) { |
| throw new NullPointerException("source == null"); |
| } |
| return new CollationElementIterator(collAsICU().getCollationElementIterator(source)); |
| } |
| |
| /** |
| * 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) { |
| // Android-changed: Switch to ICU and check for null value. |
| if (source == null) { |
| throw new NullPointerException("source == null"); |
| } |
| return new CollationElementIterator(collAsICU().getCollationElementIterator(source)); |
| } |
| |
| /** |
| * 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(); |
| } |
| // Android-changed: Switched to ICU. |
| return icuColl.compare(source, target); |
| } |
| |
| /** |
| * 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) |
| { |
| // Android-changed: Switched to ICU. |
| if (source == null) { |
| return null; |
| } |
| return new CollationKeyICU(source, icuColl.getCollationKey(source)); |
| } |
| |
| /** |
| * Standard override; no change in semantics. |
| */ |
| public Object clone() { |
| // Android-changed: remove special case for cloning. |
| return super.clone(); |
| } |
| |
| /** |
| * 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; |
| // Android-changed: delegate to super class, as that already compares icuColl. |
| return super.equals(obj); |
| } |
| |
| /** |
| * Generates the hash code for the table-based collation object |
| */ |
| public int hashCode() { |
| // Android-changed: Switched to ICU. |
| return icuColl.hashCode(); |
| } |
| |
| // Android-added: collAsIcu helper method. |
| private android.icu.text.RuleBasedCollator collAsICU() { |
| return (android.icu.text.RuleBasedCollator) icuColl; |
| } |
| |
| // Android-removed: private constants and fields. |
| } |
