/
AVLTreeReader.java
608 lines (544 loc) · 14.4 KB
/
AVLTreeReader.java
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package org.sirix.index.avltree;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import java.io.PrintStream;
import java.util.ArrayDeque;
import java.util.Deque;
import javax.annotation.Nonnegative;
import org.sirix.access.Move;
import org.sirix.access.Moved;
import org.sirix.api.NodeCursor;
import org.sirix.api.PageReadTrx;
import org.sirix.api.visitor.VisitResultType;
import org.sirix.api.visitor.Visitor;
import org.sirix.exception.SirixIOException;
import org.sirix.index.IndexType;
import org.sirix.index.SearchMode;
import org.sirix.index.avltree.interfaces.References;
import org.sirix.node.DocumentRootNode;
import org.sirix.node.Kind;
import org.sirix.node.NullNode;
import org.sirix.node.interfaces.Node;
import org.sirix.node.interfaces.Record;
import org.sirix.node.interfaces.StructNode;
import org.sirix.node.interfaces.immutable.ImmutableNode;
import org.sirix.page.PageKind;
import org.sirix.settings.Fixed;
import org.sirix.utils.LogWrapper;
import org.slf4j.LoggerFactory;
import com.google.common.base.Optional;
import com.google.common.collect.AbstractIterator;
/**
* Simple AVLTreeReader (balanced binary search-tree -- based on BaseX(.org)
* version).
*
* @author Johannes Lichtenberger, University of Konstanz
*
* @param <K>
* the key to search for or insert
* @param <V>
* the value
*/
public final class AVLTreeReader<K extends Comparable<? super K>, V extends References>
implements NodeCursor {
/** {@link LogWrapper} reference. */
private static final LogWrapper LOGWRAPPER = new LogWrapper(
LoggerFactory.getLogger(AVLTreeReader.class));
/** Determines if tree is closed or not. */
private boolean mClosed;
/** Strong reference to currently selected node. */
private Node mCurrentNode;
/** {@link PageReadTrx} for persistent storage. */
final PageReadTrx mPageReadTrx;
/** Page kind. */
final PageKind mPageKind;
/** Index number. */
final int mIndex;
/** Determines movement of the internal cursor. */
public enum MoveCursor {
/** Cursor should be moved document root. */
TO_DOCUMENT_ROOT,
/** Cursor should not be moved. */
NO_MOVE
}
/**
* Private constructor.
*
* @param pageReadTrx
* {@link PageReadTrx} for persistent storage
* @param type
* kind of index
* @param index
* the index number
*/
private AVLTreeReader(final PageReadTrx pageReadTrx, final IndexType type,
final int index) {
mPageReadTrx = checkNotNull(pageReadTrx);
switch (type) {
case PATH:
mPageKind = PageKind.PATHPAGE;
break;
case CAS:
mPageKind = PageKind.CASPAGE;
break;
case NAME:
mPageKind = PageKind.NAMEPAGE;
break;
default:
throw new IllegalStateException();
}
mClosed = false;
mIndex = index;
try {
Optional<? extends Record> node = mPageReadTrx.getRecord(
Fixed.DOCUMENT_NODE_KEY.getStandardProperty(), mPageKind, index);
if (node.isPresent()) {
mCurrentNode = (Node) node.get();
} else {
throw new IllegalStateException(
"Node couldn't be fetched from persistent storage!");
}
} catch (final SirixIOException e) {
LOGWRAPPER.error(e.getMessage(), e);
}
}
/**
* Get a new instance.
*
* @param pageReadTrx
* {@link PageReadTrx} for persistent storage
* @param type
* type of index
* @return new tree instance
*/
public static <K extends Comparable<? super K>, V extends References> AVLTreeReader<K, V> getInstance(
final PageReadTrx pageReadTrx, final IndexType type,
final @Nonnegative int index) {
return new AVLTreeReader<K, V>(pageReadTrx, type, index);
}
/**
* Dump the AVLTree in preorder.
*
* @param out
* {@link PrintStream} to print to
*/
public void dump(final PrintStream out) {
moveToDocumentRoot();
if (((DocumentRootNode) getNode()).hasFirstChild()) {
moveToFirstChild();
} else {
return;
}
internalDump(out);
}
// Internal function to dump data to a PrintStream instance.
private void internalDump(final PrintStream out) {
out.println(getAVLNode());
final long nodeKey = getAVLNode().getNodeKey();
if (getAVLNode().hasLeftChild()) {
moveToFirstChild();
internalDump(out);
}
moveTo(nodeKey);
if (getAVLNode().hasRightChild()) {
moveToLastChild();
internalDump(out);
}
}
/**
* Get the {@link AVLNode}.
*
* @return {@link AVLNode} instance
*/
AVLNode<K, V> getAVLNode() {
if (mCurrentNode.getKind() != Kind.DOCUMENT) {
@SuppressWarnings("unchecked")
final AVLNode<K, V> node = (AVLNode<K, V>) mCurrentNode;
return node;
}
return null;
}
/**
* Finds the specified key in the index and returns its value.
*
* @param key
* key to be found
* @param mode
* the search mode
* @return {@link Optional} reference (with the found value, or a reference
* which indicates that the value hasn't been found)
*/
public Optional<V> get(final K key, final SearchMode mode) {
moveToDocumentRoot();
if (!((DocumentRootNode) getNode()).hasFirstChild()) {
return Optional.absent();
}
moveToFirstChild();
AVLNode<K, V> node = getAVLNode();
while (true) {
final int c = mode.compare(key, node.getKey());
if (c == 0) {
return Optional.fromNullable(node.getValue());
}
final boolean moved = c < 0 ? moveToFirstChild().hasMoved()
: moveToLastChild().hasMoved();
if (moved) {
node = getAVLNode();
} else {
break;
}
}
return Optional.absent();
}
/**
* Iterator supporting different search modes.
*
* @author Johannes Lichtenberger
*
*/
public final class AVLNodeIterator extends AbstractIterator<AVLNode<K, V>> {
/** Determines if it's the first call. */
private boolean mFirst;
/** All AVLNode keys which are part of the result sequence. */
private final Deque<Long> mKeys;
/** Start node key. */
private final long mKey;
/**
* Constructor.
*
* @param nodeKey
* node key to start from, root node of AVLTree is selected if
* {@code Fixed.DOCUMENT_NODE_KEY.getStandardProperty} is
* specified.
*/
public AVLNodeIterator(final long nodeKey) {
mFirst = true;
mKeys = new ArrayDeque<>();
checkArgument(nodeKey >= 0, "nodeKey must be >= 0!");
mKey = nodeKey;
}
@Override
protected AVLNode<K, V> computeNext() {
if (!mFirst) {
if (!mKeys.isEmpty()) {
// Subsequent results.
final AVLNode<K, V> node = moveTo(mKeys.pop()).get().getAVLNode();
stackOperation(node);
return node;
}
return endOfData();
}
// First search.
mFirst = false;
boolean moved = moveTo(mKey).hasMoved();
if (mKey == Fixed.DOCUMENT_NODE_KEY.getStandardProperty()) {
moved = moveToFirstChild().hasMoved();
}
if (moved) {
final AVLNode<K, V> node = getAVLNode();
stackOperation(node);
return node;
}
return endOfData();
}
private void stackOperation(final AVLNode<K, V> node) {
if (node.hasRightChild()) {
final AVLNode<K, V> right = moveToLastChild().get().getAVLNode();
mKeys.push(right.getNodeKey());
}
moveTo(node.getNodeKey());
if (node.hasLeftChild()) {
final AVLNode<K, V> left = moveToFirstChild().get().getAVLNode();
mKeys.push(left.getNodeKey());
}
}
}
// /**
// * Iterator supporting different search modes.
// *
// * @author Johannes Lichtenberger
// *
// */
// public final class AVLNodeSearchIterator extends
// AbstractIterator<AVLNode<K, V>> {
//
// /** The key to search. */
// private final K mKey;
//
// /** Determines if it's the first call. */
// private boolean mFirst;
//
// /** All AVLNode keys which are part of the result sequence. */
// private final Deque<Long> mKeys;
//
// /** Search mode. */
// private final SearchMode mMode;
//
// /**
// * Constructor.
// *
// * @param key
// * the key to search for
// * @param mode
// * the search mode
// */
// public AVLNodeSearchIterator(final K key, final SearchMode mode) {
// mKey = checkNotNull(key);
// mFirst = true;
// mKeys = new ArrayDeque<>();
// mMode = checkNotNull(mode);
// }
//
// @Override
// protected AVLNode<K, V> computeNext() {
// if (!mFirst) {
// if (!mKeys.isEmpty()) {
// // Subsequent results.
// final AVLNode<K, V> node = moveTo(mKeys.pop()).get().getAVLNode();
// stackOperation(node);
// if (mMode.compare(mKey, node.getKey()) == 0) {
// return node;
// }
// }
// return endOfData();
// }
//
// // First search.
// mFirst = false;
// final Optional<V> result = get(mKey, mMode);
// if (result.isPresent()) {
// final AVLNode<K, V> node = getAVLNode();
// stackOperation(node);
// return node;
// }
// return endOfData();
// }
//
// private void stackOperation(final AVLNode<K, V> node) {
// if (node.hasRightChild()) {
// final AVLNode<K, V> right = moveToLastChild().get().getAVLNode();
// mKeys.push(right.getNodeKey());
// }
// moveTo(node.getNodeKey());
// if (node.hasLeftChild()) {
// final AVLNode<K, V> left = moveToFirstChild().get().getAVLNode();
// mKeys.push(left.getNodeKey());
// }
// }
// }
/**
* Returns the number of index entries.
*
* @return number of index entries
*/
public long size() {
return ((DocumentRootNode) moveToDocumentRoot().get().getNode())
.getDescendantCount();
}
@Override
public void close() throws Exception {
mClosed = true;
}
/**
* Make sure that the path summary is not yet closed when calling this method.
*/
final void assertNotClosed() {
if (mClosed) {
throw new IllegalStateException("Path summary is already closed.");
}
}
/**
* Set current node.
*
* @param node
*/
public void setCurrentNode(final AVLNode<K, V> node) {
mCurrentNode = checkNotNull(node);
}
/**
* Get the structural node of the current node.
*
* @return structural node
*/
private StructNode getStructuralNode() {
if (mCurrentNode instanceof StructNode) {
return (StructNode) mCurrentNode;
} else {
return new NullNode(mCurrentNode);
}
}
@Override
public boolean hasNode(final long key) {
final long currKey = mCurrentNode.getNodeKey();
final boolean moved = moveTo(key).hasMoved();
final Move<AVLTreeReader<K, V>> movedCursor = moveTo(currKey);
assert movedCursor.hasMoved() == true : "Must be moveable back!";
return moved;
}
@Override
public boolean hasParent() {
return mCurrentNode.hasParent();
}
@Override
public boolean hasFirstChild() {
return getStructuralNode().hasFirstChild();
}
@Override
public boolean hasLastChild() {
if (mCurrentNode instanceof AVLNode) {
return getAVLNode().hasRightChild();
}
return false;
}
@Override
public boolean hasLeftSibling() {
return getStructuralNode().hasLeftSibling();
}
@Override
public boolean hasRightSibling() {
assertNotClosed();
return getStructuralNode().hasRightSibling();
}
@Override
public VisitResultType acceptVisitor(Visitor visitor) {
throw new UnsupportedOperationException();
}
@Override
public Move<AVLTreeReader<K, V>> moveTo(final long nodeKey) {
assertNotClosed();
if (nodeKey == Fixed.NULL_NODE_KEY.getStandardProperty()) {
return Move.notMoved();
}
// Remember old node and fetch new one.
final Node oldNode = mCurrentNode;
Optional<? extends Node> newNode;
try {
// Immediately return node from item list if node key negative.
@SuppressWarnings("unchecked")
final Optional<? extends Node> node = (Optional<? extends Node>) mPageReadTrx
.getRecord(nodeKey, mPageKind, mIndex);
newNode = node;
} catch (final SirixIOException e) {
newNode = Optional.absent();
}
if (newNode.isPresent()) {
mCurrentNode = newNode.get();
return Move.moved(this);
} else {
mCurrentNode = oldNode;
return Move.notMoved();
}
}
@Override
public Move<AVLTreeReader<K, V>> moveToDocumentRoot() {
return moveTo(Fixed.DOCUMENT_NODE_KEY.getStandardProperty());
}
@Override
public Move<AVLTreeReader<K, V>> moveToParent() {
return moveTo(mCurrentNode.getParentKey());
}
@Override
public Move<AVLTreeReader<K, V>> moveToFirstChild() {
assertNotClosed();
if (mCurrentNode instanceof AVLNode) {
final AVLNode<K, V> node = getAVLNode();
if (!node.hasLeftChild()) {
return Moved.notMoved();
}
return moveTo(node.getLeftChildKey());
}
return moveTo(((DocumentRootNode) mCurrentNode).getFirstChildKey());
}
@Override
public Move<AVLTreeReader<K, V>> moveToLastChild() {
if (mCurrentNode instanceof AVLNode) {
final AVLNode<K, V> node = getAVLNode();
if (!node.hasRightChild()) {
return Moved.notMoved();
}
return moveTo(node.getRightChildKey());
}
return Move.notMoved();
}
@Override
public Move<? extends NodeCursor> moveToPrevious() {
return moveToParent();
}
@Override
public Move<? extends NodeCursor> moveToNext() {
if (mCurrentNode instanceof AVLNode) {
@SuppressWarnings("unchecked")
AVLNode<K, V> node = (AVLNode<K, V>) mCurrentNode;
if (node.hasLeftChild()) {
moveToFirstChild();
} else if (node.hasRightChild()) {
moveToLastChild();
} else {
while (moveToParent().get().getNode() instanceof AVLNode
&& !hasLastChild()) {
}
if (getNode() instanceof AVLNode) {
return Move.moved(moveToLastChild().get());
} else {
return Move.notMoved();
}
}
}
return Move.moved(moveToFirstChild().get());
}
@Override
public Move<AVLTreeReader<K, V>> moveToLeftSibling() {
return Move.notMoved();
}
@Override
public Move<AVLTreeReader<K, V>> moveToRightSibling() {
return Move.notMoved();
}
@Override
public long getNodeKey() {
return mCurrentNode.getNodeKey();
}
@Override
public Kind getRightSiblingKind() {
return Kind.UNKNOWN;
}
@Override
public Kind getLeftSiblingKind() {
return Kind.UNKNOWN;
}
@Override
public Kind getFirstChildKind() {
final Kind firstChildKind = moveToFirstChild().get().getKind();
moveToParent();
return firstChildKind;
}
@Override
public Kind getLastChildKind() {
final Kind lastChildKind = moveToLastChild().get().getKind();
moveToParent();
return lastChildKind;
}
@Override
public Kind getParentKind() {
if (hasParent()) {
if (mCurrentNode.getParentKey() == Fixed.DOCUMENT_NODE_KEY
.getStandardProperty()) {
return Kind.DOCUMENT;
} else {
final long nodeKey = mCurrentNode.getNodeKey();
final Kind parentKind = moveToParent().get().getKind();
moveTo(nodeKey);
return parentKind;
}
}
return Kind.UNKNOWN;
}
@Override
public Kind getKind() {
return mCurrentNode.getKind();
}
@Override
public ImmutableNode getNode() {
return mCurrentNode;
}
}