dmitrys 2003/09/25 14:41:51
Modified: src/java/org/apache/lucene/index IndexReader.java
Log:
Submitted by: Christoph Goller via Dmitry
Slightly modified patch from Christoph to prohibit modifications of an
index by readers that have a stale view of it.
Revision Changes Path
1.18 +35 -16 jakarta-lucene/src/java/org/apache/lucene/index/IndexReader.java
Index: IndexReader.java
===================================================================
RCS file:
/home/cvs/jakarta-lucene/src/java/org/apache/lucene/index/IndexReader.java,v
retrieving revision 1.17
retrieving revision 1.18
diff -u -r1.17 -r1.18
--- IndexReader.java 12 Aug 2003 15:05:03 -0000 1.17
+++ IndexReader.java 25 Sep 2003 21:41:51 -0000 1.18
@@ -80,11 +80,15 @@
public abstract class IndexReader {
protected IndexReader(Directory directory) {
this.directory = directory;
+ segmentInfosAge = Long.MAX_VALUE;
}
Directory directory;
private Lock writeLock;
+ //used to determine whether index has chaged since reader was opened
+ private long segmentInfosAge;
+
/** Returns an IndexReader reading the index in an FSDirectory in the named
path. */
public static IndexReader open(String path) throws IOException {
@@ -101,18 +105,24 @@
public static IndexReader open(final Directory directory) throws IOException{
synchronized (directory) { // in- & inter-process sync
return (IndexReader)new Lock.With(directory.makeLock("commit.lock"),
IndexWriter.COMMIT_LOCK_TIMEOUT) {
- public Object doBody() throws IOException {
- SegmentInfos infos = new SegmentInfos();
- infos.read(directory);
- if (infos.size() == 1) // index is optimized
- return new SegmentReader(infos.info(0), true);
-
- SegmentReader[] readers = new SegmentReader[infos.size()];
- for (int i = 0; i < infos.size(); i++)
- readers[i] = new SegmentReader(infos.info(i), i==infos.size()-1);
- return new SegmentsReader(directory, readers);
- }
- }.run();
+ public Object doBody() throws IOException {
+ IndexReader result = null;
+
+ SegmentInfos infos = new SegmentInfos();
+ infos.read(directory);
+ if (infos.size() == 1) { // index is optimized
+ result = new SegmentReader(infos.info(0), true);
+ } else {
+ SegmentReader[] readers = new SegmentReader[infos.size()];
+ for (int i = 0; i < infos.size(); i++)
+ readers[i] = new SegmentReader(infos.info(i), i==infos.size()-1);
+ result = new SegmentsReader(directory, readers);
+ }
+
+ result.segmentInfosAge = lastModified(directory);
+ return result;
+ }
+ }.run();
}
}
@@ -229,8 +239,8 @@
<p><ul>
Term => <docNum, freq,
<pos<sub>1</sub>, pos<sub>2</sub>, ...
- pos<sub>freq-1</sub>>
- ><sup>*</sup>
+ pos<sub>freq-1</sub>>
+ ><sup>*</sup>
</ul>
<p> This positional information faciliates phrase and proximity searching.
<p>The enumeration is ordered by document number. Each document number is
@@ -258,6 +268,15 @@
if (!writeLock.obtain(IndexWriter.WRITE_LOCK_TIMEOUT)) // obtain write lock
throw new IOException("Index locked for write: " + writeLock);
this.writeLock = writeLock;
+
+ // we have to check whether index has changed since this reader was opened.
+ // if so, this reader is no longer valid for deletion
+ if(lastModified(directory) > segmentInfosAge){
+ this.writeLock.release();
+ this.writeLock = null;
+ throw new IOException(
+ "IndexReader out of date and no longer valid for deletion");
+ }
}
doDelete(docNum);
}
@@ -276,8 +295,8 @@
int n = 0;
try {
while (docs.next()) {
- delete(docs.doc());
- n++;
+ delete(docs.doc());
+ n++;
}
} finally {
docs.close();
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