/**
Copyright (C) SYSTAP, LLC DBA Blazegraph 2006-2016. All rights reserved.
Contact:
SYSTAP, LLC DBA Blazegraph
2501 Calvert ST NW #106
Washington, DC 20008
licenses@blazegraph.com
This program 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; version 2 of the License.
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package com.bigdata.resources;
import java.util.UUID;
import com.bigdata.btree.BTree;
import com.bigdata.btree.Checkpoint;
import com.bigdata.btree.IndexMetadata;
import com.bigdata.btree.IndexSegmentStore;
import com.bigdata.btree.keys.IKeyBuilder;
import com.bigdata.btree.keys.KeyBuilder;
import com.bigdata.io.SerializerUtil;
import com.bigdata.mdi.IResourceMetadata;
import com.bigdata.mdi.SegmentMetadata;
import com.bigdata.rawstore.IRawStore;
import com.bigdata.util.Bytes;
/**
* {@link BTree} mapping {@link IndexSegmentStore} <em>createTime</em>s to
* {@link IResourceMetadata} records. The keys are the long integers
* (commitTimes) followed by the index segment UUID to break ties (this is not
* the scale-out index UUID, but the UUID of the specific index segment). The
* values are {@link IResourceMetadata} objects.
* <p>
* Note: Access to this object MUST be synchronized.
* <p>
* Note: This is used as a transient data structure that is populated from the
* file system by the {@link ResourceManager}.
*/
public class IndexSegmentIndex extends BTree {
/**
* Instance used to encode the timestamp into the key.
*/
final private IKeyBuilder keyBuilder = new KeyBuilder(Bytes.SIZEOF_LONG
+ Bytes.SIZEOF_UUID);
/**
* Create a transient instance.
*
* @return The new instance.
*/
static public IndexSegmentIndex createTransient() {
final IndexMetadata metadata = new IndexMetadata(UUID.randomUUID());
metadata.setBTreeClassName(IndexSegmentIndex.class.getName());
return (IndexSegmentIndex) BTree.createTransient(metadata);
}
/**
* Load from the store.
*
* @param store
* The backing store.
* @param checkpoint
* The {@link Checkpoint} record.
* @param metadata
* The metadata record for the index.
*/
public IndexSegmentIndex(IRawStore store, Checkpoint checkpoint, IndexMetadata metadata, boolean readOnly) {
super(store, checkpoint, metadata, readOnly);
}
/**
* Encodes the commit time into a key.
*
* @param commitTime
* The commit time.
* @param The
* UUID of the resource.
*
* @return The corresponding key.
*/
protected byte[] getKey(long commitTime,UUID uuid) {
return keyBuilder.reset().append(commitTime).append(uuid).getKey();
}
/**
* Add an entry under the commitTime and resource UUID associated with the
* {@link IResourceMetadata} record.
*
* @param resourceMetadata
* The {@link IResourceMetadata} record.
*
* @exception IllegalArgumentException
* if <i>commitTime</i> is <code>0L</code>.
* @exception IllegalArgumentException
* if <i>resourceMetadata</i> is <code>null</code>.
* @exception IllegalArgumentException
* if there is already an entry registered under for the
* given timestamp.
*/
synchronized public void add(final SegmentMetadata resourceMetadata) {
if (resourceMetadata == null)
throw new IllegalArgumentException();
assert resourceMetadata.isIndexSegment();
final long createTime = resourceMetadata.getCreateTime();
if (createTime == 0L)
throw new IllegalArgumentException();
final byte[] key = getKey(createTime,resourceMetadata.getUUID());
if(super.contains(key)) {
throw new IllegalArgumentException("entry exists: timestamp="
+ createTime);
}
// add a serialized entry to the persistent index.
super.insert(key, SerializerUtil.serialize(resourceMetadata));
}
}