/**
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.btree;
import java.io.IOException;
import com.bigdata.btree.AbstractBTreeTupleCursor.AbstractCursorPosition;
import com.bigdata.btree.IndexSegment.ImmutableNodeFactory.ImmutableLeaf;
import com.bigdata.btree.data.ILeafData;
import com.bigdata.btree.data.INodeData;
import com.bigdata.btree.raba.IRaba;
import com.bigdata.btree.raba.ReadOnlyKeysRaba;
import com.bigdata.btree.raba.ReadOnlyValuesRaba;
import com.bigdata.io.AbstractFixedByteArrayBuffer;
import com.bigdata.io.FixedByteArrayBuffer;
import com.bigdata.service.Event;
import com.bigdata.service.EventResource;
import com.bigdata.service.EventType;
/**
* An index segment is read-only btree corresponding to some key range of a
* potentially distributed index. The file format of the index segment includes
* a metadata record, the leaves of the segment in key order, and the nodes of
* the segment in an arbitrary order. It is possible to map or buffer the part
* of the file containing the index nodes or the entire file depending on
* application requirements.
* <p>
* Note: iterators returned by this class do not support removal (the nodes and
* leaves will all refuse mutation operations).
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class IndexSegment extends AbstractBTree {//implements ILocalBTreeView {
/**
* Type safe reference to the backing store.
*/
private final IndexSegmentStore fileStore;
/**
* Iff events are being reported.
*/
private volatile Event openCloseEvent = null;
// /**
// * An LRU for {@link ImmutableLeaf}s. This cache takes advantage of the
// * fact that the {@link LeafIterator} can read leaves without navigating
// * down the node hierarchy. This reference is set to <code>null</code>
// * if the {@link IndexSegment} is {@link #close()}d.
// */
// private ConcurrentWeakValueCacheWithTimeout<Long, ImmutableLeaf> leafCache;
// /**
// * Return the approximate #of open leaves and zero if the
// * {@link IndexSegment} is not open.
// */
// final public int getOpenLeafCount() {
//
// final ConcurrentWeakValueCacheWithTimeout<Long, ImmutableLeaf> tmp = leafCache;
//
// if (tmp == null) {
//
// return 0;
//
// }
//
// return tmp.size();
//
// }
//
// /**
// * The approximate #of bytes in the in-memory {@link IndexSegment} leaves
// * -or- ZERO (0) if the {@link IndexSegment} is closed.
// */
// public long getOpenLeafByteCount() {
//
// final ConcurrentWeakValueCacheWithTimeout<Long, ImmutableLeaf> tmp = leafCache;
//
// if (tmp == null)
// return 0L;
//
// final Iterator<WeakReference<ImmutableLeaf>> itr = tmp.iterator();
//
// long leafByteCount = 0;
//
// while (itr.hasNext()) {
//
// final ImmutableLeaf leaf = itr.next().get();
//
// if (leaf != null) {
//
// leafByteCount += fileStore.getByteCount(leaf.identity);
//
// }
//
// }
//
// return leafByteCount;
//
// }
@Override
final public int getHeight() {
// Note: fileStore.checkpoint is now final. reopen() is not required.
// reopen();
return fileStore.getCheckpoint().height;
}
@Override
final public long getNodeCount() {
// Note: fileStore.checkpoint is now final. reopen() is not required.
// reopen();
return fileStore.getCheckpoint().nnodes;
}
@Override
final public long getLeafCount() {
// Note: fileStore.checkpoint is now final. reopen() is not required.
// reopen();
return fileStore.getCheckpoint().nleaves;
}
@Override
final public long getEntryCount() {
// Note: fileStore.checkpoint is now final. reopen() is not required.
// reopen();
return fileStore.getCheckpoint().nentries;
}
@Override
final public ICheckpoint getCheckpoint() {
return fileStore.getCheckpoint();
}
@Override
public long getRecordVersion() {
return getCheckpoint().getRecordVersion();
}
@Override
public long getMetadataAddr() {
return getCheckpoint().getMetadataAddr();
}
@Override
public long getRootAddr() {
return getCheckpoint().getRootAddr();
}
@Override
public void setLastCommitTime(long lastCommitTime) {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public long writeCheckpoint() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public Checkpoint writeCheckpoint2() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public IDirtyListener getDirtyListener() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public void setDirtyListener(IDirtyListener listener) {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public long handleCommit(long commitTime) {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public void invalidate(Throwable t) {
// NOP. Not a mutable index.
}
/**
* {@inheritDoc}
* <p>
* Overridden to be thread-safe without requiring any locks.
*/
public String toString() {
/*
* I moved to code to generate the human friendly representation into
* this class in order to avoid any locking. Taking a lock in toString()
* just makes me nervous. Most of the information is in the
* IndexSegmentCheckpoint, which is a final reference on the
* IndexSegmentStore. The rest of the information is on the
* IndexMetadata object, which is also final on the IndexSegmentStore.
*
* We could probably rely on the overrides of the relevant access
* methods on IndexSegment, e.g., getEntryCount(), etc. and just use
* super.toString(). However, it seems safer and more future proof to
* directly access the relevant fields from within this implementation.
*/
final StringBuilder sb = new StringBuilder();
sb.append(getClass().getSimpleName());
sb.append("{ ");
// Note: Guaranteed available on the IndexSegmentStore.
final IndexMetadata metadata = fileStore.getIndexMetadata();
if (metadata.getName() != null) {
sb.append("name=" + metadata.getName());
} else {
sb.append("uuid=" + metadata.getIndexUUID());
}
// Note: Guaranteed available on the IndexSegmentStore.
final IndexSegmentCheckpoint chk = fileStore.getCheckpoint();
// Note: [branchingFactor is final on AbstractBTree
sb.append(", m=" + branchingFactor);//getBranchingFactor());
sb.append(", height=" + chk.height);
sb.append(", entryCount=" + chk.nentries);
sb.append(", nodeCount=" + chk.nnodes);
sb.append(", leafCount=" + chk.nleaves);
sb.append(", lastCommitTime=" + chk.commitTime);
sb.append("}");
return sb.toString();
}
// /**
// * Returns ZERO (0) in order to disable the read-retention queue.
// * <p>
// * Note: The read-retention queue is <em>disabled</em> for the
// * {@link IndexSegment}. Instead the {@link IndexSegment} relies on the
// * write-retention queue (all touched nodes and leaves are placed on that
// * queue) and its {@link #leafCache}. The capacity of the write-retention
// * queue is the right order of magnitude to fully buffer the visited nodes
// * of an {@link IndexSegment} while the {@link #leafCache} capacity and
// * whether or not the nodes region are fully buffered may be used to control
// * the responsiveness for leaves.
// */
// @Override
// final protected int getReadRetentionQueueCapacity() {
//
// return 0;
//
// }
//
// @Override
// final protected int getReadRetentionQueueScan() {
//
// return 0;
//
// }
/**
* Open a read-only index segment.
*
* @param fileStore
* The store containing the {@link IndexSegment}.
*
* @see IndexSegmentStore#loadIndexSegment()
*/
public IndexSegment(final IndexSegmentStore fileStore) {
super(fileStore,//
ImmutableNodeFactory.INSTANCE,//
true, // always read-only
fileStore.getIndexMetadata(),//
fileStore.getIndexMetadata().getIndexSegmentRecordCompressorFactory()
);
// Type-safe reference to the backing store.
this.fileStore = (IndexSegmentStore) fileStore;
_reopen();
}
/**
* Extended to also close the backing file.
*/
@Override
public void close() {
if (root == null) {
throw new IllegalStateException(ERROR_CLOSED);
}
fileStore.lock.lock();
try {
// // release the leaf cache.
// leafCache.clear();
// leafCache = null;
// release buffers and hard reference to the root node.
super.close();
// close the backing file (can be re-opened).
fileStore.close();
if (openCloseEvent != null) {
openCloseEvent.end();
openCloseEvent = null;
}
} finally {
fileStore.lock.unlock();
}
}
/**
* {@inheritDoc}
* <p>
* Overridden to a more constrained type.
*/
@Override
final public IndexSegmentStore getStore() {
return fileStore;
}
/**
* Extended to explicitly close the {@link IndexSegment} and the backing
* {@link IndexSegmentStore}. A finalizer is necessary for this class
* because we maintain {@link IndexSegment}s in a weak value cache and do
* not explicitly close then before their reference is cleared. This leads
* to the {@link IndexSegmentStore} being left open. The finalizer fixes
* that.
*/
@Override
protected void finalize() throws Throwable {
if (isOpen()) {
if (INFO)
log.info("Closing IndexSegment: " + fileStore.getFile());
close();
}
super.finalize();
}
@Override
protected void _reopen() {
// prevent concurrent close.
fileStore.lock.lock();
try {
if (fileStore.fed != null) {
openCloseEvent = new Event(fileStore.fed, new EventResource(
fileStore.getIndexMetadata(), fileStore.file),
EventType.IndexSegmentOpenClose);
}
if (!fileStore.isOpen()) {
// reopen the store.
fileStore.reopen();
}
// this.leafCache = new ConcurrentWeakValueCacheWithTimeout<Long, ImmutableLeaf>(
// fileStore.getIndexMetadata()
// .getIndexSegmentLeafCacheCapacity(), fileStore
// .getIndexMetadata()
// .getIndexSegmentLeafCacheTimeout());
// the checkpoint record (read when the backing store is opened).
final IndexSegmentCheckpoint checkpoint = fileStore.getCheckpoint();
// true iff we should fully buffer the nodes region of the index
// segment.
final boolean bufferNodes = metadata.getIndexSegmentBufferNodes();
if (checkpoint.nnodes > 0 && bufferNodes) {
try {
/*
* Read the index nodes from the file into a buffer. If
* there are no index nodes (that is if everything fits in
* the root leaf of the index) then we skip this step.
*
* Note: We always read in the root in IndexSegment#_open()
* and hold a hard reference to the root while the
* IndexSegment is open.
*/
fileStore.bufferIndexNodes();
} catch (IOException ex) {
throw new RuntimeException(ex);
}
}
/*
* Read the root node.
*
* Note: if this is an empty index segment then we actually create a
* new empty root leaf since there is nothing to be read from the
* file.
*/
final long addrRoot = checkpoint.addrRoot;
if (addrRoot == 0L) {
// empty index segment; create an empty root leaf.
this.root = new ImmutableLeaf(this);
} else {
// read the root node/leaf from the file.
this.root = readNodeOrLeaf(addrRoot);
}
if (checkpoint.addrBloom != 0L) {
try {
/*
* Read the optional bloom filter from the backing store.
*/
bloomFilter = fileStore.readBloomFilter();
} catch (IOException ex) {
throw new RuntimeException(ex);
}
}
// // report on the event.
// ResourceManager.openIndexSegment(null/* name */, fileStore
// .getFile().toString(), fileStore.size());
} finally {
fileStore.lock.unlock();
}
}
// /**
// * Extended to not place hard references to leaves into the
// * {@link AbstractBTree#writeRetentionQueue} since {@link IndexSegment}
// * leaves are normally held by the {@link #leafCache} for iterators and
// * single-tuple operations do not require that we hold a hard reference to
// * the leaf.
// */
// @Override
// protected void touch(final AbstractNode<?> node) {
//
// if (node.isLeaf())
// return;
//
// super.touch(node);
//
// }
@Override
final public BloomFilter getBloomFilter() {
// make sure the index is open.
reopen();
/*
* return the reference. The bloom filter is read when the file is
* (re-)opened. if the reference is null then there is no bloom filter.
*/
return bloomFilter;
}
// final public boolean isReadOnly() {
//
// return true;
//
// }
/**
* The value of the {@link IndexSegmentCheckpoint#commitTime} field.
*/
final public long getLastCommitTime() {
return fileStore.getCheckpoint().commitTime;
}
/**
* @throws UnsupportedOperationException
* always since the {@link IndexSegment} is read-only.
*/
final public long getRevisionTimestamp() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
/*
* ISimpleBTree (disallows mutation operations, applies the optional bloom
* filter when present).
*/
/**
* Operation is disallowed - the counter is only stored in the mutable
* {@link BTree}.
*/
final public ICounter getCounter() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
/**
* @throws UnsupportedOperationException
* always.
*/
@Override
final public void removeAll() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
/**
* Type-safe method reads the leaf from the backing file given the address
* of that leaf. This method is suitable for ad-hoc examination of the leaf
* or for a low-level iterator based on the prior/next leaf addresses.
* <p>
* Note: The parent is NOT set on the leaf but it MAY be defined if the leaf
* was read from cache.
*
* @param addr
* The address of a leaf.
*
* @return That leaf.
*/
public ImmutableLeaf readLeaf(final long addr) {
final ImmutableLeaf leaf = (ImmutableLeaf) readNodeOrLeaf(addr);
// Note: not necessary. Was already touched on the global LRU by
// readNodeOrLeaf().
// /*
// * This method is called in the context of the direct access methods for
// * the first and last leaves and the sequential scans of linked leaves.
// * Normally, the leaf would have been touched during top-down
// * navigation. However, the contexts in which this is invoked do not
// * involve top-down navigation so we touch the leaf on the LRU so it
// * will be strongly held for a while.
// */
// globalLRU.add(leaf.getDelegate());
return leaf;
}
/**
* Extended to transparently re-open the backing {@link IndexSegmentStore}.
*/
@Override
protected AbstractNode<?> readNodeOrLeaf(final long addr) {
// final Long tmp = Long.valueOf(addr);
//
// {
//
// // test the leaf cache.
// final ImmutableLeaf leaf = leafCache.get(tmp);
//
// if (leaf != null) {
//
// // cache hit.
// return leaf;
//
// }
//
// }
if (!fileStore.isOpen()) {
/*
* Make sure the backing store is open.
*
* Note: DO NOT call IndexSegment#reopen() here since it invokes
* this method in order to read in the root node!
*/
fileStore.reopen();
}
// read the node or leaf
final AbstractNode<?> node = super.readNodeOrLeaf(addr);
// if (node.isLeaf()) {
//
// /*
// * Put the leaf in the LRU cache.
// */
//
// final ImmutableLeaf leaf = (ImmutableLeaf) node;
//
// /*
// * Synchronize on the cache first to make sure that the leaf has not
// * been concurrently entered into the cache.
// */
//
// synchronized (leafCache) {
//
// if (leafCache.get(tmp) == null) {
//
// leafCache.put(tmp, leaf);//, false/* dirty */);
//
// }
//
// }
//
// }
return node;
}
public ImmutableLeaf findLeaf(final byte[] key) {
if (key == null)
throw new IllegalArgumentException();
assert rangeCheck(key, true/*allowUpperBound*/);
if (getStore().getCheckpoint().height == 0) {
/*
* When only the root leaf exists, any key is spanned by that node.
*/
return (ImmutableLeaf) getRoot();
}
return readLeaf( findLeafAddr( key ) );
}
/**
* Find the address of the leaf that would span the key.
*
* @param key
* The key
*
* @return The address of the leaf which would span that key.
*
* @throws IllegalArgumentException
* if the <i>key</i> is <code>null</code>.
* @throws RuntimeException
* if the key does not lie within the optional key-range
* constraints for an index partition.
*/
public long findLeafAddr(final byte[] key) {
if (key == null)
throw new IllegalArgumentException();
assert rangeCheck(key, true/*allowUpperBound*/);
final int height = getStore().getCheckpoint().height;
if (height == 0) {
/*
* When only the root leaf exists, any key is spanned by that node.
*/
return getStore().getCheckpoint().addrRoot;
}
final IndexSegmentAddressManager am = getStore().getAddressManager();
AbstractNode<?> node = getRootOrFinger(key);
int i = 0;
while(true) {
final int childIndex = ((Node) node).findChild(key);
final long childAddr = ((Node) node).getChildAddr(childIndex);
if(am.isLeafAddr(childAddr)) {
// This is a leaf address so we are done.
return childAddr;
}
// descend the node hierarchy.
node = (Node)((Node)node).getChild(childIndex);
i++;
assert i <= height : "Exceeded tree height";
}
}
/*
* INodeFactory
*/
/**
* Factory for immutable nodes and leaves used by the {@link NodeSerializer}.
*/
protected static class ImmutableNodeFactory implements INodeFactory {
public static final INodeFactory INSTANCE = new ImmutableNodeFactory();
private ImmutableNodeFactory() {
}
public Leaf allocLeaf(final AbstractBTree btree, final long addr,
final ILeafData data) {
return new ImmutableLeaf(btree, addr, data);
}
public Node allocNode(final AbstractBTree btree, final long addr,
final INodeData data) {
return new ImmutableNode(btree, addr, data);
}
/**
* Immutable node throws {@link UnsupportedOperationException} for the
* public mutator API but does not try to override all low-level
* mutation behaviors.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan
* Thompson</a>
* @version $Id$
*/
public static class ImmutableNode extends Node {
/**
* @param btree
* @param addr
* @param data
*/
protected ImmutableNode(final AbstractBTree btree, final long addr,
final INodeData data) {
super(btree, addr, data);
}
@Override
public void delete() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public Tuple insert(byte[] key, byte[] val, boolean deleted, boolean putIfAbsent,
long timestamp, Tuple tuple) {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public Tuple remove(byte[] key, Tuple tuple) {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
}
/**
* A double-linked, read-only, empty leaf. This is used for the root
* leaf of an empty {@link IndexSegment}.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan
* Thompson</a>
* @version $Id: IndexSegment.java 2265 2009-10-26 12:51:06Z thompsonbry
* $
*/
private static class EmptyReadOnlyLeafData implements ILeafData {
final private boolean deleteMarkers;
final private boolean versionTimestamps;
final private boolean rawRecords;
public EmptyReadOnlyLeafData(final boolean deleteMarkers,
final boolean versionTimestamps, final boolean rawRecords) {
this.deleteMarkers = deleteMarkers;
this.versionTimestamps = versionTimestamps;
this.rawRecords = rawRecords;
}
final public boolean hasDeleteMarkers() {
return deleteMarkers;
}
final public boolean hasVersionTimestamps() {
return versionTimestamps;
}
final public boolean hasRawRecords() {
return rawRecords;
}
final public int getValueCount() {
return 0;
}
final public IRaba getValues() {
return ReadOnlyValuesRaba.EMPTY;
}
final public boolean getDeleteMarker(int index) {
throw new IndexOutOfBoundsException();
}
final public long getVersionTimestamp(int index) {
throw new IndexOutOfBoundsException();
}
final public long getRawRecord(int index) {
throw new IndexOutOfBoundsException();
}
/** Yes. */
final public boolean isDoubleLinked() {
return true;
}
/** Returns ZERO (0) since there is no next leaf. */
final public long getNextAddr() {
return 0L;
}
/** Returns ZERO (0) since there is no prior leaf. */
final public long getPriorAddr() {
return 0L;
}
final public int getKeyCount() {
return 0;
}
final public IRaba getKeys() {
return ReadOnlyKeysRaba.EMPTY;
}
final public long getMaximumVersionTimestamp() {
return Long.MIN_VALUE;
}
final public long getMinimumVersionTimestamp() {
return Long.MAX_VALUE;
}
// final public int getSpannedTupleCount() {
// return 0;
// }
final public boolean isLeaf() {
return true;
}
final public boolean isReadOnly() {
return true;
}
final public boolean isCoded() {
return true;
}
final public AbstractFixedByteArrayBuffer data() {
return FixedByteArrayBuffer.EMPTY;
}
} // class EmptyReadOnlyLeaf
/**
* Immutable leaf throws {@link UnsupportedOperationException} for the
* public mutator API but does not try to override all low-level
* mutation behaviors.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan
* Thompson</a>
* @version $Id$
*/
public static class ImmutableLeaf extends Leaf {
/**
* Ctor used when the {@link IndexSegment} is empty (no tuples) to
* create an empty (and immutable) root leaf.
*
* @param btree
*/
protected ImmutableLeaf(final AbstractBTree btree) {
// Note: This creates a _mutable_ leaf.
super(btree);
/*
* So we replace the data record with a special immutable leaf
* data object that is double-linked. This is only used for
* the empty, immutable root leaf of an IndexSegment.
*/
this.data = new EmptyReadOnlyLeafData(//
btree.getIndexMetadata().getDeleteMarkers(), //
btree.getIndexMetadata().getVersionTimestamps(),//
btree.getIndexMetadata().getRawRecords()//
);
// super(btree);
// priorAddr = nextAddr = 0L;
}
/**
* @param btree
* @param addr
* @param keys
* @param values
*/
protected ImmutableLeaf(final AbstractBTree btree, final long addr,
final ILeafData data
// , final long priorAddr,
// final long nextAddr
) {
super(btree, addr, data);
// // prior/next addrs must be known.
// assert priorAddr != -1L;
// assert nextAddr != -1L;
//
// this.priorAddr = priorAddr;
//
// this.nextAddr = nextAddr;
}
@Override
public void delete() {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public Tuple insert(byte[] key, byte[] val, boolean deleted, boolean putIfAbsent,
long timestamp, Tuple tuple) {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
@Override
public Tuple remove(byte[] key, Tuple tuple) {
throw new UnsupportedOperationException(ERROR_READ_ONLY);
}
public ImmutableLeaf nextLeaf() {
final long nextAddr = getNextAddr();
if (nextAddr == 0L) {
// no more leaves.
if (DEBUG)
log.debug("No more leaves");
return null;
}
// return the next leaf in the key order.
return ((IndexSegment) btree).readLeaf(nextAddr);
}
public ImmutableLeaf priorLeaf() {
final long priorAddr = getPriorAddr();
if (priorAddr == 0L) {
// no more leaves.
if (DEBUG)
log.debug("No more leaves");
return null;
}
// return the previous leaf in the key order.
return ((IndexSegment) btree).readLeaf(priorAddr);
}
} // class ImmutableLeaf
// /**
// * An immutable empty leaf used as the right-most child of an
// * {@link IndexSegment} {@link Node} when the right-most child was not
// * emitted by the {@link IndexSegmentBuilder}. Normally the builder will
// * assign tuples to the nodes and leaves in the {@link IndexSegmentPlan}
// * such that each separatorKey in a {@link Node} has a left and a right
// * child. When the {@link IndexSegmentPlan} was based on an overestimate
// * of the actual range count, then the right child for a separatorKey in
// * a {@link Node} is sometimes not populated and will have the address
// * 0L. When that address is dereferenced an instance of this class is
// * transparently materialized which gives the {@link Node} the
// * appearence of having both a left- and right-child for that
// * separatorKey.
// * <p>
// * Nodes other than those immediately dominating leaves can have a mock
// * rightmost leaf as a child. This means that the rightSibling of a Node
// * can be a Leaf!
// *
// * @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan
// * Thompson</a>
// * @version $Id$
// */
// static public class ImmutableEmptyLastLeaf extends ImmutableLeaf {
//
// /**
// * @param btree
// * The owning {@link IndexSegment}.
// * @param priorAddr
// * The address of the previous leaf in the natural
// * traversal order or 0L if there is no prior leaf.
// */
// public ImmutableEmptyLastLeaf(final AbstractBTree btree,
// final long priorAddr) {
//
// super( (IndexSegment) btree,
// 0L/* selfAddr */,
// new EmptyReadOnlyLeafData(//
// btree.getIndexMetadata().getDeleteMarkers(), //
// btree.getIndexMetadata().getVersionTimestamps()) {
// /**
// * Overridden to use the priorAddr field passed to
// * the constructor.
// */
// @Override
// public long getPriorAddr() {
// return priorAddr;
// }
// });
//
// }
//
// } // class ImmutableEmptyLastLeaf
} // class ImmutableNodeFactory
/**
* A position for the {@link IndexSegmentTupleCursor}.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
* @param <E>
* The generic type for objects de-serialized from the values in
* the index.
*/
static private class CursorPosition<E> extends AbstractCursorPosition<ImmutableLeaf,E> {
@SuppressWarnings("unchecked")
public IndexSegmentTupleCursor<E> getCursor() {
return (IndexSegmentTupleCursor)cursor;
}
/**
* Create position on the specified key, or on the successor of the
* specified key if that key is not found in the index.
*
* @param cursor
* The {@link ITupleCursor}.
* @param leafCursor
* The leaf cursor.
* @param index
* The index of the tuple in the <i>leaf</i>.
* @param key
* The key.
*/
public CursorPosition(IndexSegmentTupleCursor<E> cursor,
ILeafCursor<ImmutableLeaf> leafCursor, int index, byte[] key) {
super(cursor, leafCursor, index, key);
}
/**
* Copy constructor.
*
* @param p
*/
public CursorPosition(CursorPosition<E> p) {
super( p );
}
}
/**
* Implementation for an immutable {@link IndexSegment}. This
* implementation uses the prior/next leaf references for fast forward and
* reference scans of the {@link IndexSegment}.
* <p>
* Note: Since the {@link IndexSegment} is immutable it does not maintain
* listeners for concurrent modifications.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
* @param <E>
* The generic type for the objects de-serialized from the index.
*/
public static class IndexSegmentTupleCursor<E> extends
AbstractBTreeTupleCursor<IndexSegment, ImmutableLeaf, E> {
public IndexSegmentTupleCursor(final IndexSegment btree,
final Tuple<E> tuple, final byte[] fromKey, final byte[] toKey) {
super(btree, tuple, fromKey, toKey);
}
@Override
final protected CursorPosition<E> newPosition(
final ILeafCursor<ImmutableLeaf> leafCursor, final int index,
final byte[] key) {
final CursorPosition<E> pos = new CursorPosition<E>(this,
leafCursor, index, key);
return pos;
}
@Override
protected CursorPosition<E> newTemporaryPosition(
final ICursorPosition<ImmutableLeaf, E> p) {
return new CursorPosition<E>((CursorPosition<E>)p );
}
/*
* The methods below are apparently never used. BBT 12/29/2009.
*/
// /**
// * The {@link IndexSegmentStore} backing the {@link IndexSegment} for
// * that is being traversed by the {@link ITupleCursor}.
// */
// protected IndexSegmentStore getStore() {
//
// return btree.getStore();
//
// }
//
// /**
// * Return the leaf that spans the optional {@link #getFromKey()}
// * constraint and the first leaf if there is no {@link #getFromKey()}
// * constraint.
// *
// * @return The leaf that spans the first tuple that can be visited by
// * this cursor.
// *
// * @see Leaf#getKeys()
// * @see IKeyBuffer#search(byte[])
// */
// protected ImmutableLeaf getLeafSpanningFromKey() {
//
// final long addr;
//
// if (fromKey == null) {
//
// addr = getStore().getCheckpoint().addrFirstLeaf;
//
// } else {
//
// // find leaf for fromKey
// addr = getIndex().findLeafAddr(fromKey);
//
// }
//
// assert addr != 0L;
//
// final ImmutableLeaf leaf = getIndex().readLeaf(addr);
//
// assert leaf != null;
//
// return leaf;
//
// }
//
//// /**
//// * Return the leaf that spans the optional {@link #getToKey()}
//// * constraint and the last leaf if there is no {@link #getFromKey()}
//// * constraint.
//// *
//// * @return The leaf that spans the first tuple that can NOT be visited
//// * by this cursor (exclusive upper bound).
//// *
//// * @see Leaf#getKeys()
//// * @see IKeyBuffer#search(byte[])
//// */
//// protected ImmutableLeaf getLeafSpanningToKey() {
////
//// final long addr;
////
//// if (toKey == null) {
////
//// addr = getStore().getCheckpoint().addrLastLeaf;
////
//// } else {
////
//// // find leaf for toKey
//// addr = getIndex().findLeafAddr(toKey);
////
//// }
////
//// assert addr != 0L;
////
//// final ImmutableLeaf leaf = getIndex().readLeaf(addr);
////
//// assert leaf != null;
////
//// return leaf;
////
//// }
//
// /**
// * Return the leaf that spans the key. The caller must check to see
// * whether the key actually exists in the leaf.
// *
// * @param key
// * The key.
// *
// * @return The leaf spanning that key.
// */
// protected ImmutableLeaf getLeafSpanningKey(final byte[] key) {
//
// final long addr = getIndex().findLeafAddr(key);
//
// assert addr != 0L;
//
// final ImmutableLeaf leaf = getIndex().readLeaf(addr);
//
// assert leaf != null;
//
// return leaf;
//
// }
}
@Override
public ImmutableLeafCursor newLeafCursor(final SeekEnum where) {
return new ImmutableLeafCursor(where);
}
@Override
public ImmutableLeafCursor newLeafCursor(final byte[] key) {
return new ImmutableLeafCursor(key);
}
/**
* Cursor using the double-linked leaves for efficient scans.
*
* @author <a href="mailto:thompsonbry@users.sourceforge.net">Bryan Thompson</a>
* @version $Id$
*/
public class ImmutableLeafCursor implements ILeafCursor<ImmutableLeaf> {
private ImmutableLeaf leaf;
public ImmutableLeaf leaf() {
return leaf;
}
public IndexSegment getBTree() {
return IndexSegment.this;
}
public ImmutableLeafCursor clone() {
return new ImmutableLeafCursor(this);
}
/**
* Copy constructor.
*
* @param src
*/
private ImmutableLeafCursor(final ImmutableLeafCursor src) {
if (src == null)
throw new IllegalArgumentException();
this.leaf = src.leaf;
}
public ImmutableLeafCursor(final SeekEnum where) {
switch (where) {
case First:
first();
break;
case Last:
last();
break;
default:
throw new AssertionError("Unknown seek directive: " + where);
}
}
public ImmutableLeafCursor(final byte[] key) {
seek(key);
}
public ImmutableLeaf seek(final byte[] key) {
leaf = findLeaf(key);
return leaf;
}
public ImmutableLeaf seek(final ILeafCursor<ImmutableLeaf> src) {
if (src == null)
throw new IllegalArgumentException();
if (src == this) {
// NOP
return leaf;
}
if (src.getBTree() != IndexSegment.this) {
throw new IllegalArgumentException();
}
return leaf = src.leaf();
}
public ImmutableLeaf first() {
final long addr = getStore().getCheckpoint().addrFirstLeaf;
leaf = readLeaf(addr);
return leaf;
}
public ImmutableLeaf last() {
final long addr = getStore().getCheckpoint().addrLastLeaf;
leaf = readLeaf(addr);
return leaf;
}
public ImmutableLeaf next() {
final ImmutableLeaf l = leaf.nextLeaf();
if (l == null)
return null;
leaf = l;
return l;
}
public ImmutableLeaf prior() {
final ImmutableLeaf l = leaf.priorLeaf();
if (l == null)
return null;
leaf = l;
return l;
}
}
public BTree getMutableBTree() {
throw new UnsupportedOperationException();
}
public int getSourceCount() {
return 1;
}
public AbstractBTree[] getSources() {
return new AbstractBTree[]{this};
}
// @Override
// ByteBuffer readRawRecord(final long addr) {
//
// // read from the backing store.
// return getStore().read(addr);
//
// }
}