org.aspectj.org.eclipse.jdt.internal.core.nd.db

Class BTree

java.lang.Object

org.aspectj.org.eclipse.jdt.internal.core.nd.db.BTree

public class BTree
extends java.lang.Object

Implements B-Tree search structure.

Field Summary

Fields

Modifier and Type	Field and Description
protected IBTreeComparator	cmp
protected Database	db
protected int	degree
protected int	maxChildren
protected int	maxRecords
protected int	medianRecord
protected int	minRecords
protected int	offsetChildren
static int	RECORD_SIZE
protected long	rootPointer

Constructor Summary

Constructors

Constructor and Description
BTree(Nd nd, long rootPointer, IBTreeComparator cmp)
BTree(Nd nd, long rootPointer, int degree, IBTreeComparator cmp) Constructor.

Method Summary

Modifier and Type	Method and Description
boolean	accept(IBTreeVisitor visitor) Visit all nodes beginning when the visitor comparator returns >= 0 until the visitor visit returns falls.
void	delete(long record) Deletes the specified record from the B-tree.
void	destruct()
protected long	getChild(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk, long node, int index)
static ITypeFactory<BTree>	getFactory(IBTreeComparator cmp)
static ITypeFactory<BTree>	getFactory(int degree, IBTreeComparator cmp)
java.lang.String	getInvariantsErrorReport() Debugging method for checking B-tree invariants
protected long	getRecord(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk, long node, int index)
protected long	getRoot()
long	insert(long record) Inserts the record into the b-tree.
void	mergeNodes(org.aspectj.org.eclipse.jdt.internal.core.nd.db.BTree.BTNode src, org.aspectj.org.eclipse.jdt.internal.core.nd.db.BTree.BTNode keyProvider, int kIndex, org.aspectj.org.eclipse.jdt.internal.core.nd.db.BTree.BTNode dst) Merge node 'src' onto the right side of node 'dst' using node 'keyProvider' as the source of the median key.
protected void	putChild(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk, long node, int index, long child)
protected void	putRecord(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk, long node, int index, long record)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

RECORD_SIZE

public static final int RECORD_SIZE

See Also:

Constant Field Values

db

protected final Database db

rootPointer

protected final long rootPointer

degree

protected final int degree

maxRecords

protected final int maxRecords

maxChildren

protected final int maxChildren

minRecords

protected final int minRecords

offsetChildren

protected final int offsetChildren

medianRecord

protected final int medianRecord

cmp

protected final IBTreeComparator cmp

Constructor Detail

BTree

public BTree(Nd nd,
             long rootPointer,
             IBTreeComparator cmp)

BTree

public BTree(Nd nd,
             long rootPointer,
             int degree,
             IBTreeComparator cmp)

Constructor.

Parameters:

nd - the database containing the btree

rootPointer - offset into database of the pointer to the root node

Method Detail

getFactory

public static ITypeFactory<BTree> getFactory(IBTreeComparator cmp)

getFactory

public static ITypeFactory<BTree> getFactory(int degree,
                                             IBTreeComparator cmp)

getRoot

protected long getRoot()
                throws IndexException

Throws:

IndexException

putRecord

protected final void putRecord(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk,
                               long node,
                               int index,
                               long record)

getRecord

protected final long getRecord(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk,
                               long node,
                               int index)

putChild

protected final void putChild(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk,
                              long node,
                              int index,
                              long child)

getChild

protected final long getChild(org.aspectj.org.eclipse.jdt.internal.core.nd.db.Chunk chunk,
                              long node,
                              int index)

destruct

public void destruct()

insert

public long insert(long record)
            throws IndexException

Inserts the record into the b-tree. We don't insert if the key was already there, in which case we return the record that matched. In other cases, we just return the record back.

Parameters:

record - offset of the record

Throws:

IndexException

delete

public void delete(long record)
            throws IndexException

Deletes the specified record from the B-tree.

If the specified record is not present then this routine has no effect.

Specifying a record r for which there is another record q existing in the B-tree where cmp.compare(r,q)==0 && r!=q will also have no effect

N.B. The record is not deleted itself - its storage is not deallocated. The reference to the record in the btree is deleted.

Parameters:

record - the record to delete

Throws:

IndexException

mergeNodes

public void mergeNodes(org.aspectj.org.eclipse.jdt.internal.core.nd.db.BTree.BTNode src,
                       org.aspectj.org.eclipse.jdt.internal.core.nd.db.BTree.BTNode keyProvider,
                       int kIndex,
                       org.aspectj.org.eclipse.jdt.internal.core.nd.db.BTree.BTNode dst)
                throws IndexException

Merge node 'src' onto the right side of node 'dst' using node 'keyProvider' as the source of the median key. Bounds checking is not performed.

Parameters:

src - the key to merge into dst

keyProvider - the node that provides the median key for the new node

kIndex - the index of the key in the node mid which is to become the new node's median key

dst - the node which is the basis and result of the merge

Throws:

IndexException

accept

public boolean accept(IBTreeVisitor visitor)
               throws IndexException

Visit all nodes beginning when the visitor comparator returns >= 0 until the visitor visit returns falls.

Parameters:

visitor -

Throws:

IndexException

getInvariantsErrorReport

public java.lang.String getInvariantsErrorReport()
                                          throws IndexException

Debugging method for checking B-tree invariants

Returns:

the empty String if B-tree invariants hold, otherwise a human readable report

Throws:

IndexException