| /* |
| ******************************************************************************* |
| * Copyright (C) 1996-2000, International Business Machines Corporation and * |
| * others. All Rights Reserved. * |
| ******************************************************************************* |
| * |
| * $Source: /xsrl/Nsvn/icu/icu4j/src/com/ibm/text/Attic/Transliterator.java,v $ |
| * $Date: 2001/10/25 00:01:14 $ |
| * $Revision: 1.50 $ |
| * |
| ***************************************************************************************** |
| */ |
| package com.ibm.text; |
| |
| import java.util.*; |
| import java.text.MessageFormat; |
| import java.text.ParsePosition; |
| import java.io.UnsupportedEncodingException; |
| import com.ibm.text.resources.ResourceReader; |
| import com.ibm.util.CaseInsensitiveString; |
| import com.ibm.util.Utility; |
| |
| /** |
| * <code>Transliterator</code> is an abstract class that |
| * transliterates text from one format to another. The most common |
| * kind of transliterator is a script, or alphabet, transliterator. |
| * For example, a Russian to Latin transliterator changes Russian text |
| * written in Cyrillic characters to phonetically equivalent Latin |
| * characters. It does not <em>translate</em> Russian to English! |
| * Transliteration, unlike translation, operates on characters, without |
| * reference to the meanings of words and sentences. |
| * |
| * <p>Although script conversion is its most common use, a |
| * transliterator can actually perform a more general class of tasks. |
| * In fact, <code>Transliterator</code> defines a very general API |
| * which specifies only that a segment of the input text is replaced |
| * by new text. The particulars of this conversion are determined |
| * entirely by subclasses of <code>Transliterator</code>. |
| * |
| * <p><b>Transliterators are stateless</b> |
| * |
| * <p><code>Transliterator</code> objects are <em>stateless</em>; they |
| * retain no information between calls to |
| * <code>transliterate()</code>. As a result, threads may share |
| * transliterators without synchronizing them. This might seem to |
| * limit the complexity of the transliteration operation. In |
| * practice, subclasses perform complex transliterations by delaying |
| * the replacement of text until it is known that no other |
| * replacements are possible. In other words, although the |
| * <code>Transliterator</code> objects are stateless, the source text |
| * itself embodies all the needed information, and delayed operation |
| * allows arbitrary complexity. |
| * |
| * <p><b>Batch transliteration</b> |
| * |
| * <p>The simplest way to perform transliteration is all at once, on a |
| * string of existing text. This is referred to as <em>batch</em> |
| * transliteration. For example, given a string <code>input</code> |
| * and a transliterator <code>t</code>, the call |
| * |
| * <blockquote><code>String result = t.transliterate(input); |
| * </code></blockquote> |
| * |
| * will transliterate it and return the result. Other methods allow |
| * the client to specify a substring to be transliterated and to use |
| * {@link Replaceable} objects instead of strings, in order to |
| * preserve out-of-band information (such as text styles). |
| * |
| * <p><b>Keyboard transliteration</b> |
| * |
| * <p>Somewhat more involved is <em>keyboard</em>, or incremental |
| * transliteration. This is the transliteration of text that is |
| * arriving from some source (typically the user's keyboard) one |
| * character at a time, or in some other piecemeal fashion. |
| * |
| * <p>In keyboard transliteration, a <code>Replaceable</code> buffer |
| * stores the text. As text is inserted, as much as possible is |
| * transliterated on the fly. This means a GUI that displays the |
| * contents of the buffer may show text being modified as each new |
| * character arrives. |
| * |
| * <p>Consider the simple <code>RuleBasedTransliterator</code>: |
| * |
| * <blockquote><code> |
| * th>{theta}<br> |
| * t>{tau} |
| * </code></blockquote> |
| * |
| * When the user types 't', nothing will happen, since the |
| * transliterator is waiting to see if the next character is 'h'. To |
| * remedy this, we introduce the notion of a cursor, marked by a '|' |
| * in the output string: |
| * |
| * <blockquote><code> |
| * t>|{tau}<br> |
| * {tau}h>{theta} |
| * </code></blockquote> |
| * |
| * Now when the user types 't', tau appears, and if the next character |
| * is 'h', the tau changes to a theta. This is accomplished by |
| * maintaining a cursor position (independent of the insertion point, |
| * and invisible in the GUI) across calls to |
| * <code>transliterate()</code>. Typically, the cursor will |
| * be coincident with the insertion point, but in a case like the one |
| * above, it will precede the insertion point. |
| * |
| * <p>Keyboard transliteration methods maintain a set of three indices |
| * that are updated with each call to |
| * <code>transliterate()</code>, including the cursor, start, |
| * and limit. These indices are changed by the method, and they are |
| * passed in and out via a Position object. The <code>start</code> index |
| * marks the beginning of the substring that the transliterator will |
| * look at. It is advanced as text becomes committed (but it is not |
| * the committed index; that's the <code>cursor</code>). The |
| * <code>cursor</code> index, described above, marks the point at |
| * which the transliterator last stopped, either because it reached |
| * the end, or because it required more characters to disambiguate |
| * between possible inputs. The <code>cursor</code> can also be |
| * explicitly set by rules in a <code>RuleBasedTransliterator</code>. |
| * Any characters before the <code>cursor</code> index are frozen; |
| * future keyboard transliteration calls within this input sequence |
| * will not change them. New text is inserted at the |
| * <code>limit</code> index, which marks the end of the substring that |
| * the transliterator looks at. |
| * |
| * <p>Because keyboard transliteration assumes that more characters |
| * are to arrive, it is conservative in its operation. It only |
| * transliterates when it can do so unambiguously. Otherwise it waits |
| * for more characters to arrive. When the client code knows that no |
| * more characters are forthcoming, perhaps because the user has |
| * performed some input termination operation, then it should call |
| * <code>finishTransliteration()</code> to complete any |
| * pending transliterations. |
| * |
| * <p><b>Inverses</b> |
| * |
| * <p>Pairs of transliterators may be inverses of one another. For |
| * example, if transliterator <b>A</b> transliterates characters by |
| * incrementing their Unicode value (so "abc" -> "def"), and |
| * transliterator <b>B</b> decrements character values, then <b>A</b> |
| * is an inverse of <b>B</b> and vice versa. If we compose <b>A</b> |
| * with <b>B</b> in a compound transliterator, the result is the |
| * indentity transliterator, that is, a transliterator that does not |
| * change its input text. |
| * |
| * The <code>Transliterator</code> method <code>getInverse()</code> |
| * returns a transliterator's inverse, if one exists, or |
| * <code>null</code> otherwise. However, the result of |
| * <code>getInverse()</code> usually will <em>not</em> be a true |
| * mathematical inverse. This is because true inverse transliterators |
| * are difficult to formulate. For example, consider two |
| * transliterators: <b>AB</b>, which transliterates the character 'A' |
| * to 'B', and <b>BA</b>, which transliterates 'B' to 'A'. It might |
| * seem that these are exact inverses, since |
| * |
| * <blockquote>"A" x <b>AB</b> -> "B"<br> |
| * "B" x <b>BA</b> -> "A"</blockquote> |
| * |
| * where 'x' represents transliteration. However, |
| * |
| * <blockquote>"ABCD" x <b>AB</b> -> "BBCD"<br> |
| * "BBCD" x <b>BA</b> -> "AACD"</blockquote> |
| * |
| * so <b>AB</b> composed with <b>BA</b> is not the |
| * identity. Nonetheless, <b>BA</b> may be usefully considered to be |
| * <b>AB</b>'s inverse, and it is on this basis that |
| * <b>AB</b><code>.getInverse()</code> could legitimately return |
| * <b>BA</b>. |
| * |
| * <p><b>IDs and display names</b> |
| * |
| * <p>A transliterator is designated by a short identifier string or |
| * <em>ID</em>. IDs follow the format <em>source-destination</em>, |
| * where <em>source</em> describes the entity being replaced, and |
| * <em>destination</em> describes the entity replacing |
| * <em>source</em>. The entities may be the names of scripts, |
| * particular sequences of characters, or whatever else it is that the |
| * transliterator converts to or from. For example, a transliterator |
| * from Russian to Latin might be named "Russian-Latin". A |
| * transliterator from keyboard escape sequences to Latin-1 characters |
| * might be named "KeyboardEscape-Latin1". By convention, system |
| * entity names are in English, with the initial letters of words |
| * capitalized; user entity names may follow any format so long as |
| * they do not contain dashes. |
| * |
| * <p>In addition to programmatic IDs, transliterator objects have |
| * display names for presentation in user interfaces, returned by |
| * {@link #getDisplayName}. |
| * |
| * <p><b>Factory methods and registration</b> |
| * |
| * <p>In general, client code should use the factory method |
| * <code>getInstance()</code> to obtain an instance of a |
| * transliterator given its ID. Valid IDs may be enumerated using |
| * <code>getAvailableIDs()</code>. Since transliterators are |
| * stateless, multiple calls to <code>getInstance()</code> with the |
| * same ID will return the same object. |
| * |
| * <p>In addition to the system transliterators registered at startup, |
| * user transliterators may be registered by calling |
| * <code>registerInstance()</code> at run time. To register a |
| * transliterator subclass without instantiating it (until it is |
| * needed), users may call <code>registerClass()</code>. |
| * |
| * <p><b>Composed transliterators</b> |
| * |
| * <p>In addition to built-in system transliterators like |
| * "Latin-Greek", there are also built-in <em>composed</em> |
| * transliterators. These are implemented by composing two or more |
| * component transliterators. For example, if we have scripts "A", |
| * "B", "C", and "D", and we want to transliterate between all pairs |
| * of them, then we need to write 12 transliterators: "A-B", "A-C", |
| * "A-D", "B-A",..., "D-A", "D-B", "D-C". If it is possible to |
| * convert all scripts to an intermediate script "M", then instead of |
| * writing 12 rule sets, we only need to write 8: "A~M", "B~M", "C~M", |
| * "D~M", "M~A", "M~B", "M~C", "M~D". (This might not seem like a big |
| * win, but it's really 2<em>n</em> vs. <em>n</em><sup>2</sup> - |
| * <em>n</em>, so as <em>n</em> gets larger the gain becomes |
| * significant. With 9 scripts, it's 18 vs. 72 rule sets, a big |
| * difference.) Note the use of "~" rather than "-" for the script |
| * separator here; this indicates that the given transliterator is |
| * intended to be composed with others, rather than be used as is. |
| * |
| * <p>Composed transliterators can be instantiated as usual. For |
| * example, the system transliterator "Devanagari-Gujarati" is a |
| * composed transliterator built internally as |
| * "Devanagari~InterIndic;InterIndic~Gujarati". When this |
| * transliterator is instantiated, it appears externally to be a |
| * standard transliterator (e.g., getID() returns |
| * "Devanagari-Gujarati"). |
| * |
| * <p><b>Subclassing</b> |
| * |
| * <p>Subclasses must implement the abstract method |
| * <code>handleTransliterate()</code>. <p>Subclasses should override |
| * the <code>transliterate()</code> method taking a |
| * <code>Replaceable</code> and the <code>transliterate()</code> |
| * method taking a <code>String</code> and <code>StringBuffer</code> |
| * if the performance of these methods can be improved over the |
| * performance obtained by the default implementations in this class. |
| * |
| * <p>Copyright © IBM Corporation 1999. All rights reserved. |
| * |
| * @author Alan Liu |
| * @version $RCSfile: Transliterator.java,v $ $Revision: 1.50 $ $Date: 2001/10/25 00:01:14 $ |
| */ |
| public abstract class Transliterator { |
| /** |
| * Direction constant indicating the forward direction in a transliterator, |
| * e.g., the forward rules of a RuleBasedTransliterator. An "A-B" |
| * transliterator transliterates A to B when operating in the forward |
| * direction, and B to A when operating in the reverse direction. |
| * @see RuleBasedTransliterator |
| * @see CompoundTransliterator |
| */ |
| public static final int FORWARD = 0; |
| |
| /** |
| * Direction constant indicating the reverse direction in a transliterator, |
| * e.g., the reverse rules of a RuleBasedTransliterator. An "A-B" |
| * transliterator transliterates A to B when operating in the forward |
| * direction, and B to A when operating in the reverse direction. |
| * @see RuleBasedTransliterator |
| * @see CompoundTransliterator |
| */ |
| public static final int REVERSE = 1; |
| |
| /** |
| * Position structure for incremental transliteration. This data |
| * structure defines two substrings of the text being |
| * transliterated. The first region, [contextStart, |
| * contextLimit), defines what characters the transliterator will |
| * read as context. The second region, [start, limit), defines |
| * what characters will actually be transliterated. The second |
| * region should be a subset of the first. |
| * |
| * <p>After a transliteration operation, some of the indices in this |
| * structure will be modified. See the field descriptions for |
| * details. |
| * |
| * <p>contextStart <= start <= limit <= contextLimit |
| */ |
| public static class Position { |
| |
| /** |
| * Beginning index, inclusive, of the context to be considered for |
| * a transliteration operation. The transliterator will ignore |
| * anything before this index. INPUT/OUTPUT parameter: This parameter |
| * is updated by a transliteration operation to reflect the maximum |
| * amount of antecontext needed by a transliterator. |
| */ |
| public int contextStart; |
| |
| /** |
| * Ending index, exclusive, of the context to be considered for a |
| * transliteration operation. The transliterator will ignore |
| * anything at or after this index. INPUT/OUTPUT parameter: This |
| * parameter is updated to reflect changes in the length of the |
| * text, but points to the same logical position in the text. |
| */ |
| public int contextLimit; |
| |
| /** |
| * Beginning index, inclusive, of the text to be transliteratd. |
| * INPUT/OUTPUT parameter: This parameter is advanced past |
| * characters that have already been transliterated by a |
| * transliteration operation. |
| */ |
| public int start; |
| |
| /** |
| * Ending index, exclusive, of the text to be transliteratd. |
| * INPUT/OUTPUT parameter: This parameter is updated to reflect |
| * changes in the length of the text, but points to the same |
| * logical position in the text. |
| */ |
| public int limit; |
| |
| public Position() { |
| this(0, 0, 0, 0); |
| } |
| |
| public Position(int contextStart, int contextLimit, int start) { |
| this(contextStart, contextLimit, start, contextLimit); |
| } |
| |
| public Position(int contextStart, int contextLimit, |
| int start, int limit) { |
| this.contextStart = contextStart; |
| this.contextLimit = contextLimit; |
| this.start = start; |
| this.limit = limit; |
| } |
| } |
| |
| /** |
| * Programmatic name, e.g., "Latin-Arabic". |
| */ |
| private String ID; |
| |
| /** |
| * This transliterator's filter. Any character for which |
| * <tt>filter.contains()</tt> returns <tt>false</tt> will not be |
| * altered by this transliterator. If <tt>filter</tt> is |
| * <tt>null</tt> then no filtering is applied. |
| */ |
| private UnicodeFilter filter; |
| |
| private int maximumContextLength = 0; |
| |
| /** |
| * System transliterator registry. |
| */ |
| private static TransliteratorRegistry registry; |
| |
| private static Hashtable displayNameCache; |
| |
| /** |
| * Prefix for resource bundle key for the display name for a |
| * transliterator. The ID is appended to this to form the key. |
| * The resource bundle value should be a String. |
| */ |
| private static final String RB_DISPLAY_NAME_PREFIX = "%Translit%%"; |
| |
| /** |
| * Prefix for resource bundle key for the display name for a |
| * transliterator SCRIPT. The ID is appended to this to form the key. |
| * The resource bundle value should be a String. |
| */ |
| private static final String RB_SCRIPT_DISPLAY_NAME_PREFIX = "%Translit%"; |
| |
| /** |
| * Resource bundle key for display name pattern. |
| * The resource bundle value should be a String forming a |
| * MessageFormat pattern, e.g.: |
| * "{0,choice,0#|1#{1} Transliterator|2#{1} to {2} Transliterator}". |
| */ |
| private static final String RB_DISPLAY_NAME_PATTERN = "TransliteratorNamePattern"; |
| |
| /** |
| * Resource bundle containing display name keys and the |
| * RB_RULE_BASED_IDS array. |
| * |
| * <p>If we ever integrate this with the Sun JDK, the resource bundle |
| * root will change to java.text.resources.LocaleElements |
| */ |
| private static final String RB_LOCALE_ELEMENTS = |
| "com.ibm.text.resources.LocaleElements"; |
| |
| protected static final char ID_DELIM = ';'; |
| |
| protected static final char ID_SEP = '-'; |
| |
| private static final String COPYRIGHT = |
| "\u00A9 IBM Corporation 1999. All rights reserved."; |
| |
| /** |
| * Default constructor. |
| * @param ID the string identifier for this transliterator |
| * @param filter the filter. Any character for which |
| * <tt>filter.contains()</tt> returns <tt>false</tt> will not be |
| * altered by this transliterator. If <tt>filter</tt> is |
| * <tt>null</tt> then no filtering is applied. |
| */ |
| protected Transliterator(String ID, UnicodeFilter filter) { |
| if (ID == null) { |
| throw new NullPointerException(); |
| } |
| this.ID = ID; |
| this.filter = filter; |
| } |
| |
| /** |
| * Transliterates a segment of a string, with optional filtering. |
| * |
| * @param text the string to be transliterated |
| * @param start the beginning index, inclusive; <code>0 <= start |
| * <= limit</code>. |
| * @param limit the ending index, exclusive; <code>start <= limit |
| * <= text.length()</code>. |
| * @param filter the filter. Any character for which |
| * <tt>filter.contains()</tt> returns <tt>false</tt> will not be |
| * altered by this transliterator. If <tt>filter</tt> is |
| * <tt>null</tt> then no filtering is applied. |
| * @return The new limit index. The text previously occupying <code>[start, |
| * limit)</code> has been transliterated, possibly to a string of a different |
| * length, at <code>[start, </code><em>new-limit</em><code>)</code>, where |
| * <em>new-limit</em> is the return value. |
| */ |
| public final int transliterate(Replaceable text, int start, int limit) { |
| Position pos = new Position(start, limit, start); |
| filteredTransliterate(text, pos, false); |
| return pos.limit; |
| } |
| |
| /** |
| * Transliterates an entire string in place. Convenience method. |
| * @param text the string to be transliterated |
| */ |
| public final void transliterate(Replaceable text) { |
| transliterate(text, 0, text.length()); |
| } |
| |
| /** |
| * Transliterate an entire string and returns the result. Convenience method. |
| * |
| * @param text the string to be transliterated |
| * @return The transliterated text |
| */ |
| public final String transliterate(String text) { |
| ReplaceableString result = new ReplaceableString(text); |
| transliterate(result); |
| return result.toString(); |
| } |
| |
| /** |
| * Transliterates the portion of the text buffer that can be |
| * transliterated unambiguosly after new text has been inserted, |
| * typically as a result of a keyboard event. The new text in |
| * <code>insertion</code> will be inserted into <code>text</code> |
| * at <code>index.contextLimit</code>, advancing |
| * <code>index.contextLimit</code> by <code>insertion.length()</code>. |
| * Then the transliterator will try to transliterate characters of |
| * <code>text</code> between <code>index.start</code> and |
| * <code>index.contextLimit</code>. Characters before |
| * <code>index.start</code> will not be changed. |
| * |
| * <p>Upon return, values in <code>index</code> will be updated. |
| * <code>index.contextStart</code> will be advanced to the first |
| * character that future calls to this method will read. |
| * <code>index.start</code> and <code>index.contextLimit</code> will |
| * be adjusted to delimit the range of text that future calls to |
| * this method may change. |
| * |
| * <p>Typical usage of this method begins with an initial call |
| * with <code>index.contextStart</code> and <code>index.contextLimit</code> |
| * set to indicate the portion of <code>text</code> to be |
| * transliterated, and <code>index.start == index.contextStart</code>. |
| * Thereafter, <code>index</code> can be used without |
| * modification in future calls, provided that all changes to |
| * <code>text</code> are made via this method. |
| * |
| * <p>This method assumes that future calls may be made that will |
| * insert new text into the buffer. As a result, it only performs |
| * unambiguous transliterations. After the last call to this |
| * method, there may be untransliterated text that is waiting for |
| * more input to resolve an ambiguity. In order to perform these |
| * pending transliterations, clients should call {@link |
| * #finishTransliteration} after the last call to this |
| * method has been made. |
| * |
| * @param text the buffer holding transliterated and untransliterated text |
| * @param index the start and limit of the text, the position |
| * of the cursor, and the start and limit of transliteration. |
| * @param insertion text to be inserted and possibly |
| * transliterated into the translation buffer at |
| * <code>index.contextLimit</code>. If <code>null</code> then no text |
| * is inserted. |
| * @see #handleTransliterate |
| * @exception IllegalArgumentException if <code>index</code> |
| * is invalid |
| */ |
| public final void transliterate(Replaceable text, Position index, |
| String insertion) { |
| if (index.contextStart < 0 || |
| index.start < index.contextStart || |
| index.limit < index.start || |
| index.contextLimit < index.limit || |
| text.length() < index.contextLimit) { |
| throw new IllegalArgumentException("Invalid index {" + |
| index.contextStart + ", " + |
| index.start + ", " + |
| index.limit + ", " + |
| index.contextLimit + "}, len=" + |
| text.length()); |
| } |
| |
| // int originalStart = index.contextStart; |
| if (insertion != null) { |
| text.replace(index.limit, index.limit, insertion); |
| index.limit += insertion.length(); |
| index.contextLimit += insertion.length(); |
| } |
| |
| if (index.limit > 0 && |
| UTF16.isLeadSurrogate(text.charAt(index.limit - 1))) { |
| // Oops, there is a dangling lead surrogate in the buffer. |
| // This will break most transliterators, since they will |
| // assume it is part of a pair. Don't transliterate until |
| // more text comes in. |
| return; |
| } |
| |
| filteredTransliterate(text, index, true); |
| |
| // This doesn't work once we add quantifier support. Need to rewrite |
| // this code to support quantifiers and 'use maximum backup <n>;'. |
| // |
| // index.contextStart = Math.max(index.start - getMaximumContextLength(), |
| // originalStart); |
| } |
| |
| /** |
| * Transliterates the portion of the text buffer that can be |
| * transliterated unambiguosly after a new character has been |
| * inserted, typically as a result of a keyboard event. This is a |
| * convenience method; see {@link #transliterate(Replaceable, |
| * Transliterator.Position, String)} for details. |
| * @param text the buffer holding transliterated and |
| * untransliterated text |
| * @param index the start and limit of the text, the position |
| * of the cursor, and the start and limit of transliteration. |
| * @param insertion text to be inserted and possibly |
| * transliterated into the translation buffer at |
| * <code>index.contextLimit</code>. |
| * @see #transliterate(Replaceable, Transliterator.Position, String) |
| */ |
| public final void transliterate(Replaceable text, Position index, |
| int insertion) { |
| transliterate(text, index, UTF16.valueOf(insertion)); |
| } |
| |
| /** |
| * Transliterates the portion of the text buffer that can be |
| * transliterated unambiguosly. This is a convenience method; see |
| * {@link #transliterate(Replaceable, Transliterator.Position, |
| * String)} for details. |
| * @param text the buffer holding transliterated and |
| * untransliterated text |
| * @param index the start and limit of the text, the position |
| * of the cursor, and the start and limit of transliteration. |
| * @see #transliterate(Replaceable, Transliterator.Position, String) |
| */ |
| public final void transliterate(Replaceable text, Position index) { |
| transliterate(text, index, null); |
| } |
| |
| /** |
| * Finishes any pending transliterations that were waiting for |
| * more characters. Clients should call this method as the last |
| * call after a sequence of one or more calls to |
| * <code>transliterate()</code>. |
| * @param text the buffer holding transliterated and |
| * untransliterated text. |
| * @param index the array of indices previously passed to {@link |
| * #transliterate} |
| */ |
| public final void finishTransliteration(Replaceable text, |
| Position index) { |
| filteredTransliterate(text, index, false); |
| } |
| |
| /** |
| * Abstract method that concrete subclasses define to implement |
| * keyboard transliteration. This method should transliterate all |
| * characters between <code>index.start</code> and |
| * <code>index.contextLimit</code> that can be unambiguously |
| * transliterated, regardless of future insertions of text at |
| * <code>index.contextLimit</code>. <code>index.start</code> should |
| * be advanced past committed characters (those that will not |
| * change in future calls to this method). |
| * <code>index.contextLimit</code> should be updated to reflect text |
| * replacements that shorten or lengthen the text between |
| * <code>index.start</code> and <code>index.contextLimit</code>. Upon |
| * return, neither <code>index.start</code> nor |
| * <code>index.contextLimit</code> should be less than the initial value |
| * of <code>index.start</code>. <code>index.contextStart</code> |
| * should <em>not</em> be changed. |
| * |
| * <p>Subclasses may safely assume that all characters in |
| * [index.start, index.limit) are unfiltered. In other words, the |
| * filter has already been applied by the time this method is |
| * called. See filteredTransliterate(). |
| * |
| * <p>This method is <b>not</b> for public consumption. Calling |
| * this method directly will transliterate [index.start, |
| * index.limit) without applying the filter. End user code that |
| * wants to call this method should be calling transliterate(). |
| * Subclass code that wants to call this method should probably be |
| * calling filteredTransliterate(). |
| * |
| * @param text the buffer holding transliterated and |
| * untransliterated text |
| * @param pos the start and limit of the text, the position |
| * of the cursor, and the start and limit of transliteration. |
| * @param incremental if true, assume more text may be coming after |
| * pos.contextLimit. Otherwise, assume the text is complete. |
| * @see #transliterate |
| */ |
| protected abstract void handleTransliterate(Replaceable text, |
| Position pos, boolean incremental); |
| |
| /** |
| * This method breaks up the input text into runs of unfiltered |
| * characters. It passes each such run to |
| * <subclass>.handleTransliterate(). Subclasses that can handle the |
| * filter logic more efficiently themselves may override this method. |
| * |
| * All transliteration calls in this class go through this method. |
| */ |
| protected void filteredTransliterate(Replaceable text, |
| Position index, |
| boolean incremental) { |
| if (filter == null) { |
| // Short circuit path for transliterators with no filter |
| handleTransliterate(text, index, incremental); |
| return; |
| } |
| |
| // globalLimit is the limit value for the entire operation. We |
| // set index.limit to the end of each unfiltered run before |
| // calling handleTransliterate(), so we need to maintain the real |
| // value of index.limit here. After each transliteration, we |
| // update globalLimit for insertions or deletions that have |
| // happened. |
| int globalLimit = index.limit; |
| |
| // Break the input text up. Say the input text has the form: |
| // xxxabcxxdefxx |
| // where 'x' represents a filtered character. Then we break this |
| // up into: |
| // xxxabc xxdef xx |
| // Each pass through the loop consumes a run of filtered |
| // characters (which are ignored) and a subsequent run of |
| // unfiltered characters (which are transliterated). If, at any |
| // point, we fail to consume our entire segment, we stop. |
| for (;;) { |
| // Narrow the range to be transliterated to the first segment |
| // of unfiltered characters at or after index.start. |
| |
| int c; |
| |
| // Advance compoundStart past filtered chars |
| while (index.start < globalLimit && |
| !filter.contains(c=UTF16.charAt(text, index.start))) { |
| index.start += UTF16.getCharCount(c); |
| } |
| |
| // Find the end of this run of unfiltered chars |
| index.limit = index.start; |
| while (index.limit < globalLimit && |
| filter.contains(c=UTF16.charAt(text, index.limit))) { |
| index.limit += UTF16.getCharCount(c); |
| } |
| |
| // Check to see if the unfiltered run is empty. This only |
| // happens at the end of the string when all the remaining |
| // characters are filtered. |
| if (index.limit == index.start) { |
| // assert(index.start == globalLimit); |
| break; |
| } |
| |
| int limit = index.limit; |
| |
| // Is this segment incremental? If there is additional |
| // filtered text (if limit < globalLimit) then we pass in |
| // an incremental value of FALSE to force the subclass to |
| // complete the transliteration for this segment. |
| boolean isIncrementalSegment = |
| (limit < globalLimit ? false : incremental); |
| |
| // Implement rollback. To understand the need for rollback, |
| // consider the following transliterator: |
| // |
| // "t" is "a > A;" |
| // "u" is "A > b;" |
| // "v" is a compound of "t; NFD; u" with a filter [:Ll:] |
| // |
| // Now apply "c" to the input text "a". The result is "b". But if |
| // the transliteration is done incrementally, then the NFD holds |
| // things up after "t" has already transformed "a" to "A". When |
| // finishTransliterate() is called, "A" is _not_ processed because |
| // it gets excluded by the [:Ll:] filter, and the end result is "A" |
| // -- incorrect. The problem is that the filter is applied to a |
| // partially-transliterated result, when we only want it to apply to |
| // input text. Although this example hinges on a compound |
| // transliterator containing NFD and a specific filter, it can |
| // actually happen with any transliterator which may do a partial |
| // transformation in incremental mode into characters outside its |
| // filter. |
| // |
| // There are two solutions. The first is to add two new index |
| // values to the position structure, a filteredStart and a |
| // filteredLimit. Then filteredTransliterate() can set and read |
| // these, and avoid filtering partially transliterated results. A |
| // variant of this solution is to retain an internal state object |
| // with the filtered range that is indexed by the text pointer and |
| // the position object pointer, in analogy to strtok(). The third |
| // solution involves no change to the API and no internal state |
| // cache. It is to roll back any partially transliterated results |
| // if (a) there is a filter, and (b) the transliteration is |
| // incremental. This is the solution implemented here. |
| int rollbackStart = 0; |
| int rollbackCopy = 0; |
| if (isIncrementalSegment) { |
| // Make a rollback copy at the end of the string |
| rollbackStart = index.start; |
| rollbackCopy = text.length(); |
| text.copy(rollbackStart, limit, rollbackCopy); |
| } |
| |
| // Delegate to subclass for actual transliteration. |
| handleTransliterate(text, index, isIncrementalSegment); |
| |
| int delta = index.limit - limit; // change in length |
| |
| // Adjust overall limit for insertions/deletions. Don't need |
| // to worry about contextLimit because handleTransliterate() |
| // maintains that. |
| globalLimit += delta; |
| |
| // If we failed to complete transliterate this segment, |
| // then we are done. If rollback is required, then do so. |
| if (index.start != index.limit) { |
| if (isIncrementalSegment) { |
| // Replace [rollbackStart, limit) -- this is the |
| // original filtered segment -- with |
| // [rollbackCopy, text.length()), the rollback |
| // copy, then delete the rollback copy. |
| rollbackCopy += delta; |
| int rollbackLen = text.length() - rollbackCopy; |
| |
| // Delete the partially transliterated segment |
| rollbackCopy -= index.limit - rollbackStart; |
| text.replace(rollbackStart, index.limit, ""); |
| |
| // Copy the rollback copy back |
| text.copy(rollbackCopy, text.length(), rollbackStart); |
| |
| // Delete the rollback copy |
| rollbackCopy += rollbackLen; |
| text.replace(rollbackCopy, text.length(), ""); |
| |
| // Restore indices |
| index.start = rollbackStart; |
| index.limit = limit; |
| index.contextLimit -= delta; |
| globalLimit -= delta; |
| } |
| break; |
| } else if (isIncrementalSegment) { |
| // We finished this segment; delete the rollback copy |
| rollbackCopy += delta; |
| text.replace(rollbackCopy, text.length(), ""); |
| } |
| |
| // If we did completely transliterate this |
| // segment, then repeat with the next unfiltered segment. |
| } |
| |
| // Start is valid where it is. Limit needs to be put back where |
| // it was, modulo adjustments for deletions/insertions. |
| index.limit = globalLimit; |
| } |
| |
| /** |
| * Returns the length of the longest context required by this transliterator. |
| * This is <em>preceding</em> context. The default value is zero, but |
| * subclasses can change this by calling <code>setMaximumContextLength()</code>. |
| * For example, if a transliterator translates "ddd" (where |
| * d is any digit) to "555" when preceded by "(ddd)", then the preceding |
| * context length is 5, the length of "(ddd)". |
| * |
| * @return The maximum number of preceding context characters this |
| * transliterator needs to examine |
| */ |
| protected final int getMaximumContextLength() { |
| return maximumContextLength; |
| } |
| |
| /** |
| * Method for subclasses to use to set the maximum context length. |
| * @see #getMaximumContextLength |
| */ |
| protected void setMaximumContextLength(int a) { |
| if (a < 0) { |
| throw new IllegalArgumentException("Invalid context length " + a); |
| } |
| maximumContextLength = a; |
| } |
| |
| /** |
| * Returns a programmatic identifier for this transliterator. |
| * If this identifier is passed to <code>getInstance()</code>, it |
| * will return this object, if it has been registered. |
| * @see #registerClass |
| * @see #getAvailableIDs |
| */ |
| public final String getID() { |
| return ID; |
| } |
| |
| /** |
| * Set the programmatic identifier for this transliterator. Only |
| * for use by subclasses. |
| */ |
| protected final void setID(String id) { |
| ID = id; |
| } |
| |
| /** |
| * Returns a name for this transliterator that is appropriate for |
| * display to the user in the default locale. See {@link |
| * #getDisplayName(String,Locale)} for details. |
| */ |
| public final static String getDisplayName(String ID) { |
| return getDisplayName(ID, Locale.getDefault()); |
| } |
| |
| /** |
| * Returns a name for this transliterator that is appropriate for |
| * display to the user in the given locale. This name is taken |
| * from the locale resource data in the standard manner of the |
| * <code>java.text</code> package. |
| * |
| * <p>If no localized names exist in the system resource bundles, |
| * a name is synthesized using a localized |
| * <code>MessageFormat</code> pattern from the resource data. The |
| * arguments to this pattern are an integer followed by one or two |
| * strings. The integer is the number of strings, either 1 or 2. |
| * The strings are formed by splitting the ID for this |
| * transliterator at the first '-'. If there is no '-', then the |
| * entire ID forms the only string. |
| * @param inLocale the Locale in which the display name should be |
| * localized. |
| * @see java.text.MessageFormat |
| */ |
| public static String getDisplayName(String ID, Locale inLocale) { |
| ResourceBundle bundle = ResourceBundle.getBundle( |
| RB_LOCALE_ELEMENTS, inLocale); |
| |
| // Use the registered display name, if any |
| String n = (String) displayNameCache.get(ID); |
| if (n != null) { |
| return n; |
| } |
| |
| // Use display name for the entire transliterator, if it |
| // exists. |
| try { |
| return bundle.getString(RB_DISPLAY_NAME_PREFIX + ID); |
| } catch (MissingResourceException e) {} |
| |
| try { |
| // Construct the formatter first; if getString() fails |
| // we'll exit the try block |
| MessageFormat format = new MessageFormat( |
| bundle.getString(RB_DISPLAY_NAME_PATTERN)); |
| // Construct the argument array |
| int i = ID.indexOf('-'); |
| Object[] args = (i < 0) |
| ? new Object[] { new Integer(1), ID } |
| : new Object[] { new Integer(2), ID.substring(0, i), |
| ID.substring(i+1) }; |
| |
| // Use display names for the scripts, if they exist |
| for (int j=1; j<=((i<0)?1:2); ++j) { |
| try { |
| args[j] = bundle.getString(RB_SCRIPT_DISPLAY_NAME_PREFIX + |
| (String) args[j]); |
| } catch (MissingResourceException e) {} |
| } |
| |
| // Format it using the pattern in the resource |
| return format.format(args); |
| } catch (MissingResourceException e2) {} |
| |
| // We should not reach this point unless there is something |
| // wrong with the build or the RB_DISPLAY_NAME_PATTERN has |
| // been deleted from the root RB_LOCALE_ELEMENTS resource. |
| throw new RuntimeException(); |
| } |
| |
| /** |
| * Returns the filter used by this transliterator, or <tt>null</tt> |
| * if this transliterator uses no filter. |
| */ |
| public final UnicodeFilter getFilter() { |
| return filter; |
| } |
| |
| /** |
| * Changes the filter used by this transliterator. If the filter |
| * is set to <tt>null</tt> then no filtering will occur. |
| * |
| * <p>Callers must take care if a transliterator is in use by |
| * multiple threads. The filter should not be changed by one |
| * thread while another thread may be transliterating. |
| */ |
| public void setFilter(UnicodeFilter filter) { |
| this.filter = filter; |
| } |
| |
| /** |
| * Returns a <code>Transliterator</code> object given its ID. |
| * The ID must be either a system transliterator ID or a ID registered |
| * using <code>registerClass()</code>. |
| * |
| * @param ID a valid ID, as enumerated by <code>getAvailableIDs()</code> |
| * @return A <code>Transliterator</code> object with the given ID |
| * @exception IllegalArgumentException if the given ID is invalid. |
| * @see #registerClass |
| * @see #getAvailableIDs |
| * @see #getID |
| */ |
| public static final Transliterator getInstance(String ID, int direction) { |
| return getInstance(ID, direction, -1, null); |
| } |
| |
| public static final Transliterator getInstance(String ID) { |
| return getInstance(ID, FORWARD, -1, null); |
| } |
| |
| /** |
| * Create a transliterator given a compound ID (possibly degenerate, |
| * with no ID_DELIM). If idSplitPoint >= 0 and adoptedSplitTrans != |
| * 0, then insert adoptedSplitTrans in the compound ID at offset |
| * idSplitPoint. Otherwise idSplitPoint should be -1 and |
| * adoptedSplitTrans should be 0. The resultant transliterator will |
| * be an atomic (non-compound) transliterator if this is indicated by |
| * ID. Otherwise it will be a compound translitertor. |
| */ |
| private static Transliterator getInstance(String ID, |
| int dir, |
| int idSplitPoint, |
| Transliterator adoptedSplitTrans) { |
| Vector list = new Vector(); |
| int[] ignored = new int[1]; |
| UnicodeSet[] compoundFilter = new UnicodeSet[1]; |
| StringBuffer regenID = new StringBuffer(); |
| parseCompoundID(ID, regenID, dir, idSplitPoint, adoptedSplitTrans, |
| list, ignored, compoundFilter); |
| |
| Transliterator t = null; |
| switch (list.size()) { |
| case 0: |
| t = new NullTransliterator(); |
| break; |
| case 1: |
| t = (Transliterator) list.elementAt(0); |
| break; |
| default: |
| t = new CompoundTransliterator(dir, list); |
| break; |
| } |
| t.setID(regenID.toString()); |
| if (compoundFilter[0] != null) { |
| t.setFilter(compoundFilter[0]); |
| } |
| return t; |
| } |
| |
| /** |
| * Returns a <code>Transliterator</code> object constructed from |
| * the given rule string. This will be a RuleBasedTransliterator, |
| * if the rule string contains only rules, or a |
| * CompoundTransliterator, if it contains ID blocks, or a |
| * NullTransliterator, if it contains ID blocks which parse as |
| * empty for the given direction. |
| */ |
| public static final Transliterator createFromRules(String ID, String rules, int dir) { |
| Transliterator t = null; |
| |
| TransliteratorParser parser = new TransliteratorParser(); |
| parser.parse(rules, dir); |
| |
| // NOTE: The logic here matches that in TransliteratorRegistry. |
| if (parser.idBlock.length() == 0) { |
| if (parser.data == null) { |
| // No idBlock, no data -- this is just an |
| // alias for Null |
| t = new NullTransliterator(); |
| } else { |
| // No idBlock, data != 0 -- this is an |
| // ordinary RBT_DATA. |
| t = new RuleBasedTransliterator(ID, parser.data, null); |
| } |
| } else { |
| if (parser.data == null) { |
| // idBlock, no data -- this is an alias. The ID has |
| // been munged from reverse into forward mode, if |
| // necessary, so instantiate the ID in the forward |
| // direction. |
| t = getInstance(parser.idBlock); |
| if (t != null) { |
| t.setID(ID); |
| } |
| } else { |
| // idBlock and data -- this is a compound |
| // RBT |
| t = new RuleBasedTransliterator("_", parser.data, null); |
| t = new CompoundTransliterator(ID, parser.idBlock, parser.idSplitPoint, |
| t); |
| if (parser.compoundFilter != null) { |
| t.setFilter(parser.compoundFilter); |
| } |
| } |
| } |
| |
| return t; |
| } |
| |
| public String toRules(boolean escapeUnprintable) { |
| return baseToRules(escapeUnprintable); |
| } |
| |
| protected final String baseToRules(boolean escapeUnprintable) { |
| // The base class implementation of toRules munges the ID into |
| // the correct format. That is: foo => ::foo |
| // KEEP in sync with rbt_pars |
| return "::" + getID() + ID_DELIM; |
| } |
| |
| /** |
| * Parse a compound ID (possibly a degenerate one, containing no |
| * ID_DELIM). If idSplitPoint >= 0 and adoptedSplitTrans != 0, then |
| * insert adoptedSplitTrans in the compound ID at offset idSplitPoint. |
| * Otherwise idSplitPoint should be -1 and adoptedSplitTrans should be |
| * 0. Return in the result vector the instantiated transliterator |
| * objects (one of these will be adoptedSplitTrans, if the latter was |
| * specified). These will be in order of id, so if dir is REVERSE, |
| * then the caller will have to reverse the order. |
| * |
| * @param regenID regenerated ID, reversed if appropriate, which |
| * should be applied to the final created transliterator |
| * @param splitTransIndex output parameter to receive the index in |
| * 'result' at which the adoptedSplitTrans is stored, or -1 if |
| * adoptedSplitTrans == 0 |
| * @param compoundFilter output parameter to receive the parsed |
| * compound filter, if any. It receives either the FORWARD or the |
| * REVERSE compound filter, depending on dir. |
| */ |
| static void parseCompoundID(String id, |
| StringBuffer regenID, |
| int dir, |
| int idSplitPoint, |
| Transliterator splitTrans, |
| Vector result, |
| int[] splitTransIndex, |
| UnicodeSet[] compoundFilter) { |
| regenID.setLength(0); |
| splitTransIndex[0] = -1; |
| int pos = 0; |
| int i; |
| |
| // A compound filter is a filter on an entire compound |
| // transliterator. It is indicated by the syntax [abc]; A-B; |
| // B-C or in the reverse direction A-B; B-C; ([abc]). We |
| // record the filter and its index (in terms of the result |
| // vector). |
| compoundFilter[0] = null; |
| int compoundFilterIndex = -1; |
| |
| while (pos < id.length()) { |
| // We compare (pos >= split), not (pos == split), so we can |
| // skip over whitespace (see below). |
| if (pos >= idSplitPoint && splitTrans != null) { |
| splitTransIndex[0] = result.size(); |
| result.addElement(splitTrans); |
| splitTrans = null; |
| } |
| int[] p = new int[] { pos }; |
| boolean[] sawDelimiter = new boolean[1]; |
| UnicodeSet[] cpdFilter = new UnicodeSet[1]; |
| Transliterator t = |
| parseID(id, regenID, p, sawDelimiter, cpdFilter, dir, true); |
| |
| if (p[0] == pos || (p[0] < id.length() && !sawDelimiter[0])) { |
| throw new IllegalArgumentException("Invalid ID " + id); |
| } |
| if (cpdFilter[0] != null) { |
| if (compoundFilter[0] != null) { |
| // Multiple compound filters |
| throw new IllegalArgumentException("Multiple compound filters in " + id); |
| } |
| compoundFilter[0] = cpdFilter[0]; |
| compoundFilterIndex = result.size(); |
| } |
| pos = p[0]; |
| // The return value may be NULL when, for instance, creating a |
| // REVERSE transliterator of ID "Latin-Greek()". |
| if (t != null) { |
| result.addElement(t); |
| } |
| } |
| |
| // Handle case of idSplitPoint == id.length() |
| if (pos >= idSplitPoint && splitTrans != null) { |
| splitTransIndex[0] = result.size(); |
| result.addElement(splitTrans); |
| splitTrans = null; |
| } |
| |
| // Check validity of compound filter position |
| if (compoundFilter[0] != null) { |
| if ((dir == FORWARD && compoundFilterIndex != 0) || |
| (dir == REVERSE && compoundFilterIndex != result.size())) { |
| throw new IllegalArgumentException("Compound filters misplaced in " + id); |
| } |
| } |
| } |
| |
| /** |
| * Parse a single ID, possibly including an inline filter, and return |
| * the resultant transliterator object. NOTE: If 'create' is false, |
| * then the amount of syntax checking is limited. However, the 'pos' |
| * parameter will be updated correctly, assuming the input string is |
| * valid. |
| * |
| * A trailing /;? \s* / is skipped. The parameter sawDelimiter |
| * indicates whether the ';' was seen or not. Upon return, if pos is |
| * advanced, it will either point to a non-whitespace character past |
| * the trailing ';', if any, or be equal to length(). |
| * |
| * @param ID the ID string |
| * @param regenID regenerated ID, reversed if appropriate, which |
| * should be applied to the final created transliterator. This method |
| * will append to this parameter for FORWARD direction and insert |
| * addition text at offset 0 for REVERSE direction. If create is |
| * false then this parameter is not used. |
| * @param pos INPUT-OUTPUT parameter. On input, the position of the |
| * first character to parse. On output, the position after the last |
| * character parsed. This will be a semicolon or ID.length(). In the |
| * case of an error this value will be unchanged. |
| * @param compoundFilter OUTPUT parameter to receive a compound |
| * filter, if one is parsed. When a non-null compound filter is |
| * returned then a null Transliterator pointer is returned. |
| * @param create if true, create and return the result. If false, |
| * only scan the ID, and return NULL. |
| * @return a newly created transliterator, or NULL. NULL is returned |
| * in all cases if create is false. If create is true, then NULL is |
| * returned on error, or if the ID is effectively empty. |
| * E.g. "Latin-Greek()" with dir == REVERSE. Do NOT check for NULL to |
| * determine if there was an error. Instead, check to see if pos |
| * moved. |
| */ |
| static Transliterator parseID(String ID, |
| StringBuffer regenID, |
| int[] pos, |
| boolean[] sawDelimiter, |
| UnicodeSet[] compoundFilter, |
| int dir, |
| boolean create) { |
| int limit, preDelimLimit, |
| revStart, revLimit=0, |
| idStart, idLimit, |
| setStart, setLimit; |
| |
| UnicodeSet[] fwdFilter = new UnicodeSet[1]; |
| UnicodeSet[] revFilter = new UnicodeSet[1]; |
| UnicodeSet filter = null; |
| int[] indices = new int[4]; |
| |
| parseIDBounds(ID, pos[0], false, indices, fwdFilter); |
| limit = indices[0]; |
| setStart = indices[1]; |
| setLimit = indices[2]; |
| revStart = indices[3]; |
| filter = fwdFilter[0]; |
| |
| idStart = pos[0]; |
| idLimit = limit; |
| |
| if (revStart >= 0 && revStart < limit) { |
| int revSetStart, revSetLimit; |
| parseIDBounds(ID, revStart+1, true, indices, revFilter); |
| revLimit = indices[0]; |
| revSetStart = indices[1]; |
| revSetLimit = indices[2]; |
| // we ignore indices[3] |
| |
| // revStart points to '(' |
| if (dir == REVERSE) { |
| idStart = revStart+1; |
| idLimit = revLimit; |
| setStart = revSetStart; |
| setLimit = revSetLimit; |
| filter = revFilter[0]; |
| } else { |
| idLimit = revStart; |
| } |
| // assert(revLimit < ID.length() && ID.charAt(revLimit) == ')'); |
| limit = revLimit+1; |
| } else { |
| // Ignore () exprs outside of this atomic ID, that is, in |
| // "Greek-Latin; Title()", ignore the "()" after Title when |
| // parsing Greek-Latin. |
| revStart = -1; |
| } |
| |
| // Advance limit past /\s*;?\s*/ |
| preDelimLimit = limit; |
| limit = skipSpaces(ID, limit); |
| sawDelimiter[0] = (limit < ID.length() && ID.charAt(limit) == ID_DELIM); |
| if (sawDelimiter[0]) { |
| limit = skipSpaces(ID, ++limit); |
| } |
| |
| // 'id' is the ID with the filter pattern removed and with |
| // whitespace deleted. In a Foo(Bar) ID, id is Foo for FORWARD |
| // and Bar for REVERSE. |
| String str; |
| str = ID.substring(setLimit, idLimit); |
| StringBuffer id = new StringBuffer(ID.substring(idStart, setStart)); |
| id.append(str); |
| |
| // Delete whitespace |
| int i; |
| for (i=0; i<id.length(); ++i) { |
| if (UCharacter.isWhitespace(id.charAt(i))) { |
| id.deleteCharAt(i); |
| --i; |
| } |
| } |
| |
| Transliterator t = null; |
| int sep = 0; // index of the separator ('-') in id |
| |
| // If id is empty, then we have either an empty specifier, |
| // which is illegal, or a compound filter, which is legal |
| // as long as its in the right place -- we let the caller |
| // decide that. |
| boolean isCompoundFilter = (id.length() == 0 && filter != null); |
| if (isCompoundFilter) { |
| compoundFilter[0] = (dir == REVERSE) ? revFilter[0] : fwdFilter[0]; |
| } |
| |
| else { |
| // Fix the id, if necessary, by reversing it (A-B => B-A). This |
| // is only done if the id is NOT of the form Foo(Bar). Record the |
| // position of the separator. |
| // |
| // For both A-B and Foo(Bar) ids, detect the special case of Null, |
| // whose inverse is itself. Given an ID with no separator "Foo", |
| // an abbreviation for "Any-Foo", consider the inverse to be |
| // "Foo-Any". |
| sep = id.toString().indexOf(ID_SEP); |
| if (sep < 0 && id.toString().equalsIgnoreCase(NullTransliterator.SHORT_ID)) { |
| // Handle "Null" |
| sep = id.length(); |
| } else if (dir == REVERSE && |
| id.toString().equalsIgnoreCase(NullTransliterator._ID)) { |
| // Reverse of "Any-Null" => "Null" |
| id.delete(0, sep+1); |
| sep = id.length(); |
| } else if (dir == REVERSE && revStart < 0) { |
| if (sep >= 0) { |
| str = id.substring(0, sep); |
| id.delete(0, sep+1); |
| } else { |
| str = "Any"; |
| } |
| sep = id.length(); |
| id.append(ID_SEP).append(str); |
| } else if (sep < 0 && id.length() > 0) { |
| // Don't do anything for empty IDs -- we handle these specially below |
| str = "Any-"; |
| sep = str.length() - 1; |
| id.insert(0, str); |
| } |
| |
| // If we have a reverse part of the ID, e.g., Foo(Bar), then we |
| // need to check for an empty part, which represents a Null |
| // transliterator. We return 0 (not a NullTransliterator). If we |
| // are not of the form Foo(Bar) then an empty string is illegal. |
| if (revStart >= 0 && id.length() == 0) { |
| // Ignore any filters; filters on Null are meaningless (and we |
| // can't attach them to 0 anyway) |
| filter = null; |
| } |
| |
| else if (create) { |
| StringBuffer s = new StringBuffer(); |
| |
| t = registry.get(id.toString(), s); |
| |
| if (s.length() != 0) { |
| // assert(t==0); |
| // Instantiate an alias |
| t = getInstance(s.toString(), FORWARD); |
| } |
| |
| if (t == null) { |
| // Creation failed; the ID is invalid or is an alias |
| filter = null; |
| return null; |
| } |
| |
| // Set the filter, if any. The transliterator may |
| // already have a filter on it so we need to AND any |
| // id-based filter together with it. E.g., |
| // getInstance("[abc] Latin-Foo"), where Latin-Foo is |
| // an RBT of "::[:Latin:]; a>A;". |
| // getInstance("Latin-Foo") is going to return an RBT |
| // with an a [:Latin:] filter, and we need to AND this |
| // with [abc]. |
| t.setFilter(UnicodeFilterLogic.and(filter, t.getFilter())); |
| } |
| } |
| |
| // Set the ID. This is normally just a substring of the input |
| // ID, but for reverse transliterators we need to munge A-B to |
| // B-A or Foo(Bar) to Bar(Foo). |
| if (dir == FORWARD) { |
| id.setLength(0); |
| id.append(ID.substring(pos[0], preDelimLimit)); |
| } else if (isCompoundFilter) { |
| // Change [:Foo:] to ([:Foo:]) and vice versa |
| id.setLength(0); |
| if (revStart < 0) { |
| id.append('(').append(ID.substring(setStart, setLimit)). |
| append(')'); |
| } else { |
| id.append(ID.substring(revStart+1, revLimit)); |
| } |
| } else if (revStart < 0) { |
| id.insert(sep, ID.substring(setStart, setLimit)); |
| } else { |
| // Change Foo(Bar) to Bar(Foo) |
| str = ID.substring(pos[0], revStart); |
| str = str.trim(); |
| id.setLength(0); |
| id.append(ID.substring(revStart+1, revLimit)); |
| Utility.trim(id); |
| id.append('(').append(str).append(')'); |
| } |
| Utility.trim(id); |
| |
| if (t != null) { |
| t.setID(id.toString()); |
| } |
| |
| // Regenerate ID of a compound entity |
| if (dir == FORWARD) { |
| if (regenID.length() != 0) { |
| regenID.append(ID_DELIM); |
| } |
| regenID.append(id); |
| } else { |
| if (regenID.length() != 0) { |
| regenID.insert(0, ID_DELIM); |
| } |
| regenID.insert(0, id); |
| } |
| |
| // Indicate success by bumping pos past the final /;?\s*/. |
| pos[0] = limit; |
| |
| return t; |
| } |
| |
| /** |
| * Internal method used by parseID. Given a piece of a single ID, |
| * find the boundaries of various parts. For IDs of the form |
| * Foo(Bar), this method parses the Foo, then the Bar. In each piece |
| * it locates any inline UnicodeSet pattern [setStart, setLimit) |
| * and finds the limit (this will point to either ';' or ')' or |
| * ID.length()). |
| * |
| * @param ID the ID to be parsed |
| * @param pos the index of ID at which to start |
| * @param withinParens if true, parse the Bar of Foo(Bar), stop at a |
| * close paren, and do not look for an open paren. If true then a |
| * close paren MUST be seen or false is returned; if false then the |
| * ';' delimiter is optional. |
| * @param indices[0] = limit set to the position of ';' or ')' (depending on |
| * withinParens), or ID.length() if no delimiter was found |
| * @param indices[1] = setStart set to the start of an inline filter pattern, |
| * or pos if none |
| * @param indices[2] = setLimit set to the limit of an inline filter pattern, |
| * or pos if none |
| * @param indices[3] = revStart if not withinParens then set to the position of the |
| * first '(', which may be > limit; otherwise set to -1 |
| * @param filter set to a newly created UnicodeSet object for the |
| * inline filter pattern, if any; OWNED BY THE CALLER |
| * |
| * @return true if the pattern is valid, false is there is an invalid |
| * UnicodeSet pattern or if withinParens is true and no close paren is |
| * seen. |
| */ |
| private static void parseIDBounds(String ID, |
| int pos, |
| boolean withinParens, |
| int[] indices, |
| UnicodeSet[] filter) { |
| int limit; |
| int setStart; |
| int setLimit; |
| int revStart; |
| |
| char endDelimiter = withinParens ? ')' : ID_DELIM; |
| limit = ID.indexOf(endDelimiter, pos); |
| if (limit < 0) { |
| if (withinParens) { |
| //return false; |
| throw new IllegalArgumentException("Missing closing parenthesis in " + ID); |
| } |
| limit = ID.length(); |
| } |
| setStart = ID.indexOf('[', pos); |
| revStart = withinParens ? -1 : ID.indexOf('(', pos); |
| |
| if (setStart >= 0 && setStart < limit && |
| (revStart < 0 || setStart < revStart)) { |
| ParsePosition ppos = new ParsePosition(setStart); |
| // TODO Improve performance by scanning the UnicodeSet pattern |
| // without actually constructing it, if create is false. That |
| // is, create a method like this one for UnicodeSet. |
| filter[0] = new UnicodeSet(); |
| filter[0].applyPattern(ID, ppos, null, true); |
| setLimit = ppos.getIndex(); |
| if (limit < setLimit) { |
| limit = ID.indexOf(endDelimiter, setLimit); |
| if (limit < 0) { |
| if (withinParens) { |
| //return false; |
| throw new IllegalArgumentException("Missing closing parenthesis in " + ID); |
| } |
| limit = ID.length(); |
| } |
| } |
| if (revStart >= 0 && revStart < setLimit) { |
| revStart = ID.indexOf(')', setLimit); |
| } |
| } else { |
| setStart = setLimit = pos; |
| } |
| indices[0] = limit; |
| indices[1] = setStart; |
| indices[2] = setLimit; |
| indices[3] = revStart; |
| } |
| |
| /** |
| * If pos is the index of a space in str, then advance it over that |
| * space and any immediately subsequent ones. |
| */ |
| private static int skipSpaces(String str, |
| int pos) { |
| while (pos < str.length() && |
| UCharacter.isWhitespace(str.charAt(pos))) { |
| ++pos; |
| } |
| return pos; |
| } |
| |
| /** |
| * Returns this transliterator's inverse. See the class |
| * documentation for details. This implementation simply inverts |
| * the two entities in the ID and attempts to retrieve the |
| * resulting transliterator. That is, if <code>getID()</code> |
| * returns "A-B", then this method will return the result of |
| * <code>getInstance("B-A")</code>, or <code>null</code> if that |
| * call fails. |
| * |
| * <p>This method does not take filtering into account. The |
| * returned transliterator will have no filter. |
| * |
| * <p>Subclasses with knowledge of their inverse may wish to |
| * override this method. |
| * |
| * @return a transliterator that is an inverse, not necessarily |
| * exact, of this transliterator, or <code>null</code> if no such |
| * transliterator is registered. |
| * @see #registerClass |
| */ |
| public final Transliterator getInverse() { |
| return getInstance(ID, REVERSE); |
| } |
| |
| /** |
| * Registers a subclass of <code>Transliterator</code> with the |
| * system. This subclass must have a public constructor taking no |
| * arguments. When that constructor is called, the resulting |
| * object must return the <code>ID</code> passed to this method if |
| * its <code>getID()</code> method is called. |
| * |
| * @param ID the result of <code>getID()</code> for this |
| * transliterator |
| * @param transClass a subclass of <code>Transliterator</code> |
| * @see #unregister |
| */ |
| public static void registerClass(String ID, Class transClass, String displayName) { |
| registry.put(ID, transClass, true); |
| if (displayName != null) { |
| displayNameCache.put(new CaseInsensitiveString(ID), displayName); |
| } |
| } |
| |
| /** |
| * Register a factory object with the given ID. The factory |
| * method should return a new instance of the given transliterator. |
| * @param ID the ID of this transliterator |
| * @param factory the factory object |
| */ |
| public static void registerFactory(String ID, Factory factory) { |
| registry.put(ID, factory, true); |
| } |
| |
| /** |
| * Unregisters a transliterator or class. This may be either |
| * a system transliterator or a user transliterator or class. |
| * |
| * @param ID the ID of the transliterator or class |
| * @see #registerClass |
| */ |
| public static void unregister(String ID) { |
| displayNameCache.remove(new CaseInsensitiveString(ID)); |
| registry.remove(ID); |
| } |
| |
| /** |
| * Returns an enumeration over the programmatic names of registered |
| * <code>Transliterator</code> objects. This includes both system |
| * transliterators and user transliterators registered using |
| * <code>registerClass()</code>. The enumerated names may be |
| * passed to <code>getInstance()</code>. |
| * |
| * @return An <code>Enumeration</code> over <code>String</code> objects |
| * @see #getInstance |
| * @see #registerClass |
| */ |
| public static final Enumeration getAvailableIDs() { |
| return registry.getAvailableIDs(); |
| } |
| |
| public static final Enumeration getAvailableSources() { |
| return registry.getAvailableSources(); |
| } |
| |
| public static final Enumeration getAvailableTargets(String source) { |
| return registry.getAvailableTargets(source); |
| } |
| |
| public static final Enumeration getAvailableVariants(String source, |
| String target) { |
| return registry.getAvailableVariants(source, target); |
| } |
| |
| /** |
| * Method for subclasses to use to obtain a character in the given |
| * string, with filtering. If the character at the given offset |
| * is excluded by this transliterator's filter, then U+FFFE is returned. |
| * |
| * <p><b>Note:</b> Most subclasses that implement |
| * handleTransliterator() will <em>not</em> want to use this |
| * method, since characters they see are already filtered. Only |
| * subclasses with special requirements, such as those overriding |
| * filteredTransliterate(), should need this method. |
| * |
| * @deprecated the new architecture provides filtering at the top |
| * level. This method will be removed Dec 31 2001. |
| */ |
| protected char filteredCharAt(Replaceable text, int i) { |
| char c; |
| UnicodeFilter filter = getFilter(); |
| return (filter == null) ? text.charAt(i) : |
| (filter.contains(c = text.charAt(i)) ? c : '\uFFFE'); |
| } |
| |
| static { |
| registry = new TransliteratorRegistry(); |
| |
| // The display name cache starts out empty |
| displayNameCache = new Hashtable(); |
| |
| // Read the index file and populate the registry. |
| // Each line of the index file is either blank, a '#' comment, |
| // or a colon-delimited line. In the latter case the first |
| // field is the ID being defined. The second field is one of |
| // three strings: "file", "internal", or "alias". Remaining |
| // fields vary according the value fo the second field. See |
| // the index file itself for further documentation. |
| ResourceReader r = new ResourceReader("Transliterator_index.txt"); |
| for (;;) { |
| String line = null; |
| try { |
| line = r.readLine(); |
| } catch (java.io.IOException e) {} |
| if (line == null) { |
| break; |
| } |
| // Skip over whitespace |
| int pos = 0; |
| while (pos < line.length() && |
| Character.isWhitespace(line.charAt(pos))) { |
| ++pos; |
| } |
| // Ignore blank lines and comments |
| if (pos == line.length() || line.charAt(pos) == '#') { |
| continue; |
| } |
| // Parse colon-delimited line |
| int colon = line.indexOf(':', pos); |
| String ID = line.substring(pos, colon); |
| pos = colon+1; |
| colon = line.indexOf(':', pos); |
| String type = line.substring(pos, colon); |
| pos = colon+1; |
| |
| if (type.equals("file") || type.equals("internal")) { |
| // Rest of line is <resource>:<encoding>:<direction> |
| // pos colon c2 |
| colon = line.indexOf(':', pos); |
| int c2 = line.indexOf(':', colon+1); |
| int dir = line.substring(c2+1).equals("FORWARD") ? |
| FORWARD : REVERSE; |
| registry.put(ID, |
| line.substring(pos, colon), // resource |
| line.substring(colon+1, c2), // encoding |
| dir, |
| !type.equals("internal")); |
| } else if (type.equals("alias")) { |
| // Rest of line is the <getInstanceArg> |
| registry.put(ID, line.substring(pos), true); |
| } else { |
| // Unknown type |
| throw new RuntimeException("Can't parse line: " + line); |
| } |
| } |
| |
| // Register non-rule-based transliterators |
| registerClass(HexToUnicodeTransliterator._ID, |
| HexToUnicodeTransliterator.class, null); |
| registerClass(UnicodeToHexTransliterator._ID, |
| UnicodeToHexTransliterator.class, null); |
| registerClass(NullTransliterator._ID, |
| NullTransliterator.class, null); |
| registerClass(RemoveTransliterator._ID, |
| RemoveTransliterator.class, null); |
| LowercaseTransliterator.register(); |
| UppercaseTransliterator.register(); |
| TitlecaseTransliterator.register(); |
| UnicodeNameTransliterator.register(); |
| NameUnicodeTransliterator.register(); |
| NormalizationTransliterator.register(); |
| } |
| |
| /** |
| * The factory interface for transliterators. Transliterator |
| * subclasses can register factory objects for IDs using the |
| * registerFactory() method of Transliterator. When invoked, the |
| * factory object will be passed the ID being instantiated. This |
| * makes it possible to register one factory method to more than |
| * one ID, or for a factory method to parameterize its result |
| * based on the variant. |
| */ |
| public static interface Factory { |
| Transliterator getInstance(String ID); |
| } |
| } |