rbtablebuilder.java

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/*
 * @(#)RBTableBuilder.java	1.9 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

/*
 * (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.util.Vector;
import sun.text.CompactIntArray;
import sun.text.IntHashtable;
import sun.text.Normalizer;
import sun.text.ComposedCharIter;
import sun.text.NormalizerUtilities;

/**
 * This class contains all the code to parse a RuleBasedCollator pattern
 * and build a RBCollationTables object from it.  A particular instance
 * of tis class exists only during the actual build process-- once an
 * RBCollationTables object has been built, the RBTableBuilder object
 * goes away.  This object carries all of the state which is only needed
 * during the build process, plus a "shadow" copy of all of the state
 * that will go into the tables object itself.  This object communicates
 * with RBCollationTables through a separate class, RBCollationTables.BuildAPI,
 * this is an inner class of RBCollationTables and provides a separate
 * private API for communication with RBTableBuilder.
 * This class isn't just an inner class of RBCollationTables itself because
 * of its large size.  For source-code readability, it seemed better for the
 * builder to have its own source file.
 */
final class RBTableBuilder {

    public RBTableBuilder(RBCollationTables.BuildAPI tables) {
        this.tables = tables;
    }

    /**
     * Create a table-based collation object with the given rules.
     * This is the main function that actually builds the tables and
     * stores them back in the RBCollationTables object.  It is called
     * ONLY by the RBCollationTables constructor.
     * @see java.util.RuleBasedCollator#RuleBasedCollator
     * @exception ParseException If the rules format is incorrect.
     */
    public void build(String pattern, int decmp) throws ParseException
    {
        boolean isSource = true;
        int i = 0;
        String expChars;
        String groupChars;
        if (pattern.length() == 0)
            throw new ParseException("Build rules empty.", 0);

        // This array maps Unicode characters to their collation ordering
        mapping = new CompactIntArray((int)RBCollationTables.UNMAPPED);

        // Normalize the build rules.  Find occurances of all decomposed characters
        // and normalize the rules before feeding into the builder.  By "normalize",
        // we mean that all precomposed Unicode characters must be converted into
        // a base character and one or more combining characters (such as accents).
        // When there are multiple combining characters attached to a base character,
        // the combining characters must be in their canonical order
        //
        Normalizer.Mode mode = NormalizerUtilities.toNormalizerMode(decmp);
        pattern = Normalizer.normalize(pattern, mode, 0, true);

        // Build the merged collation entries
        // Since rules can be specified in any order in the string
        // (e.g. "c , C < d , D < e , E .... C < CH")
        // this splits all of the rules in the string out into separate
        // objects and then sorts them.  In the above example, it merges the
        // "C < CH" rule in just before the "C < D" rule.
        //
        mPattern = new MergeCollation(pattern);
        int order = 0;

        // Now walk though each entry and add it to my own tables
        for (i = 0; i < mPattern.getCount(); ++i)
        {
            PatternEntry entry = mPattern.getItemAt(i);
            if (entry != null) {
                groupChars = entry.getChars();
                if (groupChars.length() > 1) {
		    switch(groupChars.charAt(groupChars.length()-1)) {
		    case '@':
			frenchSec = true;
			groupChars = groupChars.substring(0, groupChars.length()-1);
			break;
		    case '!':
			seAsianSwapping = true;
			groupChars = groupChars.substring(0, groupChars.length()-1);
			break;
		    }
                }

                order = increment(entry.getStrength(), order);
                expChars = entry.getExtension();

                if (expChars.length() != 0) {
                    addExpandOrder(groupChars, expChars, order);
                } else if (groupChars.length() > 1) {
                    addContractOrder(groupChars, order);
                } else {
                    char ch = groupChars.charAt(0);
                    addOrder(ch, order);
                }
            }
        }

        addComposedChars();

        commit();
        mapping.compact();

        tables.fillInTables(frenchSec, seAsianSwapping, mapping, contractTable, expandTable,
                    contractFlags, maxSecOrder, maxTerOrder);
    }

    /** Add expanding entries for pre-composed unicode characters so that this
     * collator can be used reasonably well with decomposition turned off.
     */
    private void addComposedChars() throws ParseException {
        StringBuffer buf = new StringBuffer(1);

        // Iterate through all of the pre-composed characters in Unicode
        ComposedCharIter iter = new ComposedCharIter(false, Normalizer.IGNORE_HANGUL);

        while (iter.hasNext()) {
            char c = iter.next();

            if (getCharOrder(c) == RBCollationTables.UNMAPPED) {
                //
                // We don't already have an ordering for this pre-composed character.
                //
                // First, see if the decomposed string is already in our
                // tables as a single contracting-string ordering.
                // If so, just map the precomposed character to that order.
                //
                // TODO: What we should really be doing here is trying to find the
                // longest initial substring of the decomposition that is present
                // in the tables as a contracting character sequence, and find its
                // ordering.  Then do this recursively with the remaining chars
                // so that we build a list of orderings, and add that list to
                // the expansion table.
                // That would be more correct but also significantly slower, so
                // I'm not totally sure it's worth doing.
                //
                String s = iter.decomposition();
                int contractOrder = getContractOrder(s);
                if (contractOrder != RBCollationTables.UNMAPPED) {
                    addOrder(c, contractOrder);
                } else {
                    //
                    // We don't have a contracting ordering for the entire string
                    // that results from the decomposition, but if we have orders
                    // for each individual character, we can add an expanding
                    // table entry for the pre-composed character
                    //
                    boolean allThere = true;
                    for (int i = 0; i < s.length(); i++) {
                        if (getCharOrder(s.charAt(i)) == RBCollationTables.UNMAPPED) {
                            allThere = false;
                            break;
                        }
                    }
                    if (allThere) {
                        buf.setLength(0);
                        buf.append(c);
                        addExpandOrder(buf.toString(), s, RBCollationTables.UNMAPPED);
                    }
                }
            }
        }
    }

    /**
     * Look up for unmapped values in the expanded character table.
     *
     * When the expanding character tables are built by addExpandOrder,
     * it doesn't know what the final ordering of each character
     * in the expansion will be.  Instead, it just puts the raw character
     * code into the table, adding CHARINDEX as a flag.  Now that we've
     * finished building the mapping table, we can go back and look up
     * that character to see what its real collation order is and
     * stick that into the expansion table.  That lets us avoid doing
     * a two-stage lookup later.
     */
    private final void commit()
    {
        if (expandTable != null) {
            for (int i = 0; i < expandTable.size(); i++) {
                int[] valueList = (int [])expandTable.elementAt(i);
                for (int j = 0; j < valueList.length; j++) {
                    int order = valueList[j];
                    if (order < RBCollationTables.EXPANDCHARINDEX && order > CHARINDEX) {
                        // found a expanding character that isn't filled in yet
                        char ch = (char)(order - CHARINDEX);

                        // Get the real values for the non-filled entry
                        int realValue = getCharOrder(ch);

                        if (realValue == RBCollationTables.UNMAPPED) {
                            // The real value is still unmapped, maybe it's ignorable
                            valueList[j] = IGNORABLEMASK & ch;
                        } else {
                            // just fill in the value
                            valueList[j] = realValue;
                        }
                    }
                }
            }
        }
    }
    /**
     *  Increment of the last order based on the comparison level.
     */
    private final int increment(int aStrength, int lastValue)
    {
        switch(aStrength)
        {
        case Collator.PRIMARY:
            // increment priamry order  and mask off secondary and tertiary difference
            lastValue += PRIMARYORDERINCREMENT;
            lastValue &= RBCollationTables.PRIMARYORDERMASK;
            isOverIgnore = true;
            break;
        case Collator.SECONDARY:
            // increment secondary order and mask off tertiary difference
            lastValue += SECONDARYORDERINCREMENT;
            lastValue &= RBCollationTables.SECONDARYDIFFERENCEONLY;
            // record max # of ignorable chars with secondary difference
            if (!isOverIgnore)
                maxSecOrder++;
            break;
        case Collator.TERTIARY:
            // increment tertiary order