Author: toad
Date: 2008-10-23 22:53:14 +0000 (Thu, 23 Oct 2008)
New Revision: 23064
Modified:
branches/db4o/freenet/src/freenet/support/io/SegmentedBucketChainBucket.java
Log:
This class does NOT support persistence. Explain why.
Modified:
branches/db4o/freenet/src/freenet/support/io/SegmentedBucketChainBucket.java
===================================================================
---
branches/db4o/freenet/src/freenet/support/io/SegmentedBucketChainBucket.java
2008-10-23 18:49:30 UTC (rev 23063)
+++
branches/db4o/freenet/src/freenet/support/io/SegmentedBucketChainBucket.java
2008-10-23 22:53:14 UTC (rev 23064)
@@ -16,6 +16,22 @@
/**
* Splits a large persistent file into a series of buckets, which are
collected
* into groups called segments to avoid huge transactions/memory usage.
+ *
+ * NON-PERSISTENT: This class uses persistent buckets, it stores them in the
+ * database to save memory, but the bucket itself does not support persistence.
+ * Making it support persistence cleanly requires major refactoring. The
obvious
+ * avenues are:
+ *
+ * 1. Pass DBJobRunner in to getOutputStream(), getInputStream(), free(),
+ * storeTo(). This will touch hundreds of files, mostly it is trivial though.
It
+ * will however increase the overhead for all buckets slightly.
+ * 2. Make DBJobRunner a static variable, hence there will be only one database
+ * thread for the whole VM, even in a simulation with more than one node. One
+ * difficulty with this is that the node.db4o needs to be in the correct
directory,
+ * yet the database would need to be initiated very early on.
+ *
+ * Generally we create it, write to it, call getBuckets() and clear(), anyway
...
+ *
* @author Matthew Toseland <toad at amphibian.dyndns.org> (0xE43DA450)
*/
public class SegmentedBucketChainBucket implements Bucket {
@@ -28,7 +44,6 @@
private boolean freed;
final BucketFactory bf;
private transient DBJobRunner dbJobRunner;
- boolean stored;
public SegmentedBucketChainBucket(int blockSize, BucketFactory factory,
DBJobRunner runner, int segmentSize2) {
@@ -272,7 +287,7 @@
}
public void removeFrom(ObjectContainer container) {
- // FIXME do something
+ throw new UnsupportedOperationException();
}
public void setReadOnly() {
@@ -293,10 +308,7 @@
* calling storeTo().
*/
public void storeTo(ObjectContainer container) {
- stored = true;
- dbJobRunner.removeRestartJob(killMe,
NativeThread.HIGH_PRIORITY, container);
- container.ext().store(segments, 1);
- container.ext().store(this, 1);
+ throw new UnsupportedOperationException();
}
public Bucket[] getBuckets() {
