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Diffstat (limited to 'libjava/classpath/java/text/CollationElementIterator.java')
| -rw-r--r-- | libjava/classpath/java/text/CollationElementIterator.java | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/libjava/classpath/java/text/CollationElementIterator.java b/libjava/classpath/java/text/CollationElementIterator.java new file mode 100644 index 0000000..60b148e --- /dev/null +++ b/libjava/classpath/java/text/CollationElementIterator.java @@ -0,0 +1,467 @@ +/* CollationElementIterator.java -- Walks through collation elements + Copyright (C) 1998, 1999, 2001, 2002, 2003, 2004 Free Software Foundation + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath is distributed in the hope that it will be useful, but +WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA +02110-1301 USA. + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package java.text; + +import java.util.ArrayList; + +/* Written using "Java Class Libraries", 2nd edition, plus online + * API docs for JDK 1.2 from http://www.javasoft.com. + * Status: Believed complete and correct to JDK 1.1. + */ + +/** + * This class walks through the character collation elements of a + * <code>String</code> as defined by the collation rules in an instance of + * <code>RuleBasedCollator</code>. There is no public constructor for + * this class. An instance is created by calling the + * <code>getCollationElementIterator</code> method on + * <code>RuleBasedCollator</code>. + * + * @author Aaron M. Renn (arenn@urbanophile.com) + * @author Tom Tromey (tromey@cygnus.com) + * @author Guilhem Lavaux (guilhem.lavaux@free.fr) + */ +public final class CollationElementIterator +{ + /** + * This is a constant value that is returned to indicate that the end of + * the string was encountered. + */ + public static final int NULLORDER = -1; + + /** + * This is the RuleBasedCollator this object was created from. + */ + RuleBasedCollator collator; + + /** + * This is the String that is being iterated over. + */ + String text; + + /** + * This is the index into the collation decomposition where we are currently scanning. + */ + int index; + + /** + * This is the index into the String where we are currently scanning. + */ + int textIndex; + + /** + * Array containing the collation decomposition of the + * text given to the constructor. + */ + private RuleBasedCollator.CollationElement[] text_decomposition; + + /** + * Array containing the index of the specified block. + */ + private int[] text_indexes; + + /** + * This method initializes a new instance of <code>CollationElementIterator</code> + * to iterate over the specified <code>String</code> using the rules in the + * specified <code>RuleBasedCollator</code>. + * + * @param collator The <code>RuleBasedCollation</code> used for calculating collation values + * @param text The <code>String</code> to iterate over. + */ + CollationElementIterator(RuleBasedCollator collator, String text) + { + this.collator = collator; + + setText (text); + } + + RuleBasedCollator.CollationElement nextBlock() + { + if (index >= text_decomposition.length) + return null; + + RuleBasedCollator.CollationElement e = text_decomposition[index]; + + textIndex = text_indexes[index+1]; + + index++; + + return e; + } + + RuleBasedCollator.CollationElement previousBlock() + { + if (index == 0) + return null; + + index--; + RuleBasedCollator.CollationElement e = text_decomposition[index]; + + textIndex = text_indexes[index+1]; + + return e; + } + + /** + * This method returns the collation ordering value of the next character sequence + * in the string (it may be an extended character following collation rules). + * This method will return <code>NULLORDER</code> if the + * end of the string was reached. + * + * @return The collation ordering value. + */ + public int next() + { + RuleBasedCollator.CollationElement e = nextBlock(); + + if (e == null) + return NULLORDER; + + return e.getValue(); + } + + /** + * This method returns the collation ordering value of the previous character + * in the string. This method will return <code>NULLORDER</code> if the + * beginning of the string was reached. + * + * @return The collation ordering value. + */ + public int previous() + { + RuleBasedCollator.CollationElement e = previousBlock(); + + if (e == null) + return NULLORDER; + + return e.getValue(); + } + + /** + * This method returns the primary order value for the given collation + * value. + * + * @param value The collation value returned from <code>next()</code> or <code>previous()</code>. + * + * @return The primary order value of the specified collation value. This is the high 16 bits. + */ + public static int primaryOrder(int order) + { + // From the JDK 1.2 spec. + return order >>> 16; + } + + /** + * This method resets the internal position pointer to read from the + * beginning of the <code>String</code> again. + */ + public void reset() + { + index = 0; + textIndex = 0; + } + + /** + * This method returns the secondary order value for the given collation + * value. + * + * @param value The collation value returned from <code>next()</code> or <code>previous()</code>. + * + * @return The secondary order value of the specified collation value. This is the bits 8-15. + */ + public static short secondaryOrder(int order) + { + // From the JDK 1.2 spec. + return (short) ((order >>> 8) & 255); + } + + /** + * This method returns the tertiary order value for the given collation + * value. + * + * @param value The collation value returned from <code>next()</code> or <code>previous()</code>. + * + * @return The tertiary order value of the specified collation value. This is the low eight bits. + */ + public static short tertiaryOrder(int order) + { + // From the JDK 1.2 spec. + return (short) (order & 255); + } + + /** + * This method sets the <code>String</code> that it is iterating over + * to the specified <code>String</code>. + * + * @param text The new <code>String</code> to iterate over. + * + * @since 1.2 + */ + public void setText(String text) + { + int idx = 0; + int idx_idx = 0; + int alreadyExpanded = 0; + int idxToMove = 0; + + this.text = text; + this.index = 0; + + String work_text = text.intern(); + + ArrayList a_element = new ArrayList(); + ArrayList a_idx = new ArrayList(); + + // Build element collection ordered as they come in "text". + while (idx < work_text.length()) + { + String key, key_old; + + Object object = null; + int p = 1; + + // IMPROVE: use a TreeMap with a prefix-ordering rule. + key_old = key = null; + do + { + if (object != null) + key_old = key; + key = work_text.substring (idx, idx+p); + object = collator.prefix_tree.get (key); + if (object != null && idx < alreadyExpanded) + { + RuleBasedCollator.CollationElement prefix = (RuleBasedCollator.CollationElement)object; + if (prefix.expansion != null && + prefix.expansion.startsWith(work_text.substring(0, idx))) + { + object = null; + key = key_old; + } + } + p++; + } + while (idx+p <= work_text.length()); + + if (object == null) + key = key_old; + + RuleBasedCollator.CollationElement prefix = + (RuleBasedCollator.CollationElement) collator.prefix_tree.get (key); + + /* + * First case: There is no such sequence in the database. + * We will have to build one from the context. + */ + if (prefix == null) + { + /* + * We are dealing with sequences in an expansion. They + * are treated as accented characters (tertiary order). + */ + if (alreadyExpanded > 0) + { + RuleBasedCollator.CollationElement e = + collator.getDefaultAccentedElement (work_text.charAt (idx)); + + a_element.add (e); + a_idx.add (new Integer(idx_idx)); + idx++; + alreadyExpanded--; + if (alreadyExpanded == 0) + { + /* There is not any characters left in the expansion set. + * We can increase the pointer in the source string. + */ + idx_idx += idxToMove; + idxToMove = 0; + } + else + idx_idx++; + } + else + { + /* This is a normal character. */ + RuleBasedCollator.CollationElement e = + collator.getDefaultElement (work_text.charAt (idx)); + Integer i_ref = new Integer(idx_idx); + + /* Don't forget to mark it as a special sequence so the + * string can be ordered. + */ + a_element.add (RuleBasedCollator.SPECIAL_UNKNOWN_SEQ); + a_idx.add (i_ref); + a_element.add (e); + a_idx.add (i_ref); + idx_idx++; + idx++; + } + continue; + } + + /* + * Second case: Here we have found a matching sequence. + * Here we have an expansion string prepend it to the "work text" and + * add the corresponding sorting element. We must also mark + */ + if (prefix.expansion != null) + { + work_text = prefix.expansion + + work_text.substring (idx+prefix.key.length()); + idx = 0; + a_element.add (prefix); + a_idx.add (new Integer(idx_idx)); + if (alreadyExpanded == 0) + idxToMove = prefix.key.length(); + alreadyExpanded += prefix.expansion.length()-prefix.key.length(); + } + else + { + /* Third case: the simplest. We have got the prefix and it + * has not to be expanded. + */ + a_element.add (prefix); + a_idx.add (new Integer(idx_idx)); + idx += prefix.key.length(); + /* If the sequence is in an expansion, we must decrease the + * counter. + */ + if (alreadyExpanded > 0) + { + alreadyExpanded -= prefix.key.length(); + if (alreadyExpanded == 0) + { + idx_idx += idxToMove; + idxToMove = 0; + } + } + else + idx_idx += prefix.key.length(); + } + } + + text_decomposition = (RuleBasedCollator.CollationElement[]) + a_element.toArray(new RuleBasedCollator.CollationElement[a_element.size()]); + text_indexes = new int[a_idx.size()+1]; + for (int i = 0; i < a_idx.size(); i++) + { + text_indexes[i] = ((Integer)a_idx.get(i)).intValue(); + } + text_indexes[a_idx.size()] = text.length(); + } + + /** + * This method sets the <code>String</code> that it is iterating over + * to the <code>String</code> represented by the specified + * <code>CharacterIterator</code>. + * + * @param source The <code>CharacterIterator</code> containing the new + * <code>String</code> to iterate over. + */ + public void setText(CharacterIterator source) + { + StringBuffer expand = new StringBuffer(); + + // For now assume we read from the beginning of the string. + for (char c = source.first(); + c != CharacterIterator.DONE; + c = source.next()) + expand.append(c); + + setText(expand.toString()); + } + + /** + * This method returns the current offset into the <code>String</code> + * that is being iterated over. + * + * @return The iteration index position. + * + * @since 1.2 + */ + public int getOffset() + { + return textIndex; + } + + /** + * This method sets the iteration index position into the current + * <code>String</code> to the specified value. This value must not + * be negative and must not be greater than the last index position + * in the <code>String</code>. + * + * @param offset The new iteration index position. + * + * @exception IllegalArgumentException If the new offset is not valid. + */ + public void setOffset(int offset) + { + if (offset < 0) + throw new IllegalArgumentException("Negative offset: " + offset); + + if (offset > (text.length() - 1)) + throw new IllegalArgumentException("Offset too large: " + offset); + + for (index = 0; index < text_decomposition.length; index++) + { + if (offset <= text_indexes[index]) + break; + } + /* + * As text_indexes[0] == 0, we should not have to take care whether index is + * greater than 0. It is always. + */ + if (text_indexes[index] == offset) + textIndex = offset; + else + textIndex = text_indexes[index-1]; + } + + /** + * This method returns the maximum length of any expansion sequence that + * ends with the specified collation order value. (Whatever that means). + * + * @param value The collation order value + * + * @param The maximum length of an expansion sequence. + */ + public int getMaxExpansion(int value) + { + return 1; + } +} |