com.bigdata.btree.data
Class AbstractReadOnlyNodeData<U extends IAbstractNodeData>

java.lang.Object
  com.bigdata.btree.data.AbstractReadOnlyNodeData<U>

public abstract class AbstractReadOnlyNodeData<U extends IAbstractNodeData>
extends Object

Abstract base class for a read-only view of the data for B+Tree node or leaf. The data are stored in a ByteBuffer. Access to the keys, values and other metadata are via operations on that ByteBuffer.

Version:

$Id: AbstractReadOnlyNodeData.java 2265 2009-10-26 12:51:06Z thompsonbry $

Author:

Bryan Thompson

Field Summary

protected static short	DELTA_VERSION_TIMESTAMPS Bit flag indicating that the tuple revision timestamps have been written out using an array n-bit deltas computed as maxTimestamp - minTimestamp, where n is the number of bits required to code (maxTimestamp - minTimestamp).
protected static short	FLAG_DELETE_MARKERS Bit flag for a leaf carrying delete markers for each tuple.
protected static short	FLAG_VERSION_TIMESTAMPS Bit flag for a leaf carrying version timestamps for each tuple.
protected static byte	LEAF A B+Tree leaf data record.
protected static byte	LINKED_LEAF A B+Tree leaf data record with with priorAddr and nextAddr fields.
protected static byte	NODE A B+Tree node data record.
static int	O_NEXT The offset of the long field which codes the address of the next leaf.
static int	O_PRIOR The offset of the long field which codes the address of the previous leaf.
static int	O_TYPE The offset of the byte field which codes the type of the node or leaf.
protected static int	SIZEOF_ADDR The size of a field in the data record which encodes the address of a child node or leaf.
protected static int	SIZEOF_ENTRY_COUNT The size of the field in the data record which encodes the #of tuples spanned by a node.
protected static int	SIZEOF_FLAGS The size of the field in the data record which encodes bit flags for the node or leaf.
protected static int	SIZEOF_KEYS_SIZE The size of the field in the data record which encodes the #of bytes in the coded keys (or the coded values).
protected static int	SIZEOF_NKEYS The size of the field in the data record which encodes the #of keys in the node or leaf.
protected static int	SIZEOF_TIMESTAMP The size of a field in the data record which encodes the revision timestamp of a tuple in a leaf.
protected static int	SIZEOF_TYPE The size of the field in the data record which encodes whether the data record represents a B+Tree NODE, a LEAF, or a LINKED_LEAF.
protected static int	SIZEOF_VERSION The size of the field in the data record which encodes the serialization version of the data record.
protected static short	VERSION0 Version zero is the only version defined at this time.

Constructor Summary

protected

AbstractReadOnlyNodeData() Core ctor.

Method Summary

static boolean	isLeaf(byte b) Return true iff the byte indicates an ILeafData record.
static boolean	isNode(byte b) Return true iff the byte indicates an INodeData record.

Methods inherited from class java.lang.Object

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

Field Detail

NODE

protected static final byte NODE

A B+Tree node data record.

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Constant Field Values

LEAF

protected static final byte LEAF

A B+Tree leaf data record.

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Constant Field Values

LINKED_LEAF

protected static final byte LINKED_LEAF

A B+Tree leaf data record with with priorAddr and nextAddr fields. This is used for the leaves in an IndexSegment.

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Constant Field Values

VERSION0

protected static final short VERSION0

Version zero is the only version defined at this time.

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Constant Field Values

FLAG_DELETE_MARKERS

protected static final short FLAG_DELETE_MARKERS

Bit flag for a leaf carrying delete markers for each tuple.

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Constant Field Values

FLAG_VERSION_TIMESTAMPS

protected static final short FLAG_VERSION_TIMESTAMPS

Bit flag for a leaf carrying version timestamps for each tuple.

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Constant Field Values

DELTA_VERSION_TIMESTAMPS

protected static final short DELTA_VERSION_TIMESTAMPS

Bit flag indicating that the tuple revision timestamps have been written out using an array n-bit deltas computed as maxTimestamp - minTimestamp, where n is the number of bits required to code (maxTimestamp - minTimestamp). This is a relatively compact coding.

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Constant Field Values

SIZEOF_TYPE

protected static final int SIZEOF_TYPE

The size of the field in the data record which encodes whether the data record represents a B+Tree NODE, a LEAF, or a LINKED_LEAF.

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Constant Field Values

SIZEOF_VERSION

protected static final int SIZEOF_VERSION

The size of the field in the data record which encodes the serialization version of the data record. The offset of this field depends on whether the record is a node or leaf versus a linked leaf. For a linked leaf, the version information starts after the prior/next addr fields. Otherwise it starts immediately after the type field.

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Constant Field Values

SIZEOF_FLAGS

protected static final int SIZEOF_FLAGS

The size of the field in the data record which encodes bit flags for the node or leaf.

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Constant Field Values

SIZEOF_NKEYS

protected static final int SIZEOF_NKEYS

The size of the field in the data record which encodes the #of keys in the node or leaf. The #of children in a node is always nkeys+1.

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Constant Field Values

SIZEOF_KEYS_SIZE

protected static final int SIZEOF_KEYS_SIZE

The size of the field in the data record which encodes the #of bytes in the coded keys (or the coded values). This is an int32 because it is possible that an int16 would limit the size of records for RMI.

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Constant Field Values

SIZEOF_ENTRY_COUNT

protected static final int SIZEOF_ENTRY_COUNT

The size of the field in the data record which encodes the #of tuples spanned by a node.

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Constant Field Values

SIZEOF_ADDR

protected static final int SIZEOF_ADDR

The size of a field in the data record which encodes the address of a child node or leaf.

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Constant Field Values

SIZEOF_TIMESTAMP

protected static final int SIZEOF_TIMESTAMP

The size of a field in the data record which encodes the revision timestamp of a tuple in a leaf.

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Constant Field Values

O_TYPE

public static final int O_TYPE

The offset of the byte field which codes the type of the node or leaf.

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Constant Field Values

O_PRIOR

public static final int O_PRIOR

The offset of the long field which codes the address of the previous leaf. This field IS NOT present unless the record type is LINKED_LEAF.

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Constant Field Values

O_NEXT

public static final int O_NEXT

The offset of the long field which codes the address of the next leaf. This field IS NOT present unless the record type is LINKED_LEAF.

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Constant Field Values

Constructor Detail

AbstractReadOnlyNodeData

protected AbstractReadOnlyNodeData()

Core ctor. There are two basic use cases. One when you already have the ByteBuffer with the encoded node or leaf data and one when you have a mutable Node or Leaf and you want to persist it. In the latter case, the derived class allocates a ByteBuffer and encodes the data onto that buffer.

Method Detail

isNode

public static boolean isNode(byte b)

Return true iff the byte indicates an INodeData record.

Parameters:

b - The byte value.

Returns:

isLeaf

public static boolean isLeaf(byte b)

Return true iff the byte indicates an ILeafData record. Note that this will return true for both LEAF and LINKED_LEAF.

Parameters:

b - The byte value.

Returns: