Mailing List Archive

otis 02/04/09 21:05:38

Modified: src/java/org/apache/lucene/search WildcardTermEnum.java
Log:
- A fix for bug # 7710:
http://nagoya.apache.org/bugzilla/show_bug.cgi?id=7710
Submitted by: Lee Mallabone

Revision Changes Path
1.2 +111 -39 jakarta-lucene/src/java/org/apache/lucene/search/WildcardTermEnum.java

Index: WildcardTermEnum.java
===================================================================
RCS file: /home/cvs/jakarta-lucene/src/java/org/apache/lucene/search/WildcardTermEnum.java,v
retrieving revision 1.1
retrieving revision 1.2
diff -u -r1.1 -r1.2
--- WildcardTermEnum.java 18 Sep 2001 16:29:59 -0000 1.1
+++ WildcardTermEnum.java 10 Apr 2002 04:05:38 -0000 1.2
@@ -59,10 +59,13 @@
import org.apache.lucene.index.Term;
import org.apache.lucene.index.TermEnum;

-/** Subclass of FilteredTermEnum for enumerating all terms that match the specified wildcard filter term.
-
- <p>Term enumerations are always ordered by Term.compareTo(). Each term in
- the enumeration is greater than all that precede it. */
+/**
+ * Subclass of FilteredTermEnum for enumerating all terms that match the
+ * specified wildcard filter term.
+ * <p>
+ * Term enumerations are always ordered by Term.compareTo(). Each term in
+ * the enumeration is greater than all that precede it.
+ */
public class WildcardTermEnum extends FilteredTermEnum {
Term searchTerm;
String field = "";
@@ -71,7 +74,7 @@
int preLen = 0;
boolean fieldMatch = false;
boolean endEnum = false;
-
+
/** Creates new WildcardTermEnum */
public WildcardTermEnum(IndexReader reader, Term term) throws IOException {
super(reader, term);
@@ -90,7 +93,7 @@
text = text.substring(preLen);
setEnum(reader.terms(new Term(searchTerm.field(), pre)));
}
-
+
final protected boolean termCompare(Term term) {
if (field == term.field()) {
String searchText = term.text();
@@ -101,49 +104,118 @@
endEnum = true;
return false;
}
-
+
final public float difference() {
return 1.0f;
}
-
+
final public boolean endEnum() {
return endEnum;
}
-
+
/********************************************
* String equality with support for wildcards
********************************************/
-
+
public static final char WILDCARD_STRING = '*';
public static final char WILDCARD_CHAR = '?';
-
- public static final boolean wildcardEquals(String pattern, int patternIdx, String string, int stringIdx) {
- for ( int p = patternIdx; ; ++p ) {
- for ( int s = stringIdx; ; ++p, ++s ) {
- boolean sEnd = (s >= string.length());
- boolean pEnd = (p >= pattern.length());
-
- if (sEnd && pEnd) return true;
- if (sEnd || pEnd) break;
- if (pattern.charAt(p) == WILDCARD_CHAR) continue;
- if (pattern.charAt(p) == WILDCARD_STRING) {
- int i;
- ++p;
- for (i = string.length(); i >= s; --i)
- if (wildcardEquals(pattern, p, string, i))
- return true;
- break;
- }
- if (pattern.charAt(p) != string.charAt(s)) break;
- }
- return false;
+
+ /**
+ * Determines if a word matches a wildcard pattern.
+ * <small>Work released by Granta Design Ltd after originally being done on
+ * company time.</small>
+ */
+ public static final boolean wildcardEquals(String pattern, int patternIdx,
+ String string, int stringIdx)
+ {
+ for (int p = patternIdx; ; ++p)
+ {
+ for (int s = stringIdx; ; ++p, ++s)
+ {
+ // End of string yet?
+ boolean sEnd = (s >= string.length());
+ // End of pattern yet?
+ boolean pEnd = (p >= pattern.length());
+
+ // If we're looking at the end of the string...
+ if (sEnd)
+ {
+ // Assume the only thing left on the pattern is/are wildcards
+ boolean justWildcardsLeft = true;
+
+ // Current wildcard position
+ int wildcardSearchPos = p;
+ // While we haven't found the end of the pattern,
+ // and haven't encountered any non-wildcard characters
+ while (wildcardSearchPos < pattern.length() && justWildcardsLeft)
+ {
+ // Check the character at the current position
+ char wildchar = pattern.charAt(wildcardSearchPos);
+ // If it's not a wildcard character, then there is more
+ // pattern information after this/these wildcards.
+
+ if (wildchar != WILDCARD_CHAR &&
+ wildchar != WILDCARD_STRING)
+ {
+ justWildcardsLeft = false;
+ }
+ else
+ {
+ // Look at the next character
+ wildcardSearchPos++;
+ }
+ }
+
+ // This was a prefix wildcard search, and we've matched, so
+ // return true.
+ if (justWildcardsLeft)
+ {
+ return true;
+ }
+ }
+
+ // If we've gone past the end of the string, or the pattern,
+ // return false.
+ if (sEnd || pEnd)
+ {
+ break;
+ }
+
+ // Match a single character, so continue.
+ if (pattern.charAt(p) == WILDCARD_CHAR)
+ {
+ continue;
+ }
+
+ //
+ if (pattern.charAt(p) == WILDCARD_STRING)
+ {
+ // Look at the character beyond the '*'.
+ ++p;
+ // Examine the string, starting at the last character.
+ for (int i = string.length(); i >= s; --i)
+ {
+ if (wildcardEquals(pattern, p, string, i))
+ {
+ return true;
+ }
+ }
+ break;
+ }
+ if (pattern.charAt(p) != string.charAt(s))
+ {
+ break;
+ }
+ }
+ return false;
+ }
+ }
+
+ public void close() throws IOException
+ {
+ super.close();
+ searchTerm = null;
+ field = null;
+ text = null;
}
- }
-
- public void close() throws IOException {
- super.close();
- searchTerm = null;
- field = null;
- text = null;
- }
}




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