class FanoutBucket extends InMemoryNoteBucket
InMemoryNoteBucket.prefixLen
that defines how many digits it
skips in an ObjectId before it gets to the digits matching table
.
The root tree has prefixLen == 0
, and thus does not skip any digits.
For ObjectId "c0ffee...", the note (if it exists) will be stored within the
bucket table[0xc0]
.
The first level tree has prefixLen == 2
, and thus skips the first two
digits. For the same example "c0ffee..." object, its note would be found
within the table[0xff]
bucket (as first 2 digits "c0" are skipped).
Each subtree is loaded on-demand, reducing startup latency for reads that
only need to examine a few objects. However, due to the rather uniform
distribution of the SHA-1 hash that is used for ObjectIds, accessing 256
objects is very likely to load all of the subtrees into memory.
A FanoutBucket must be parsed from a tree object by NoteParser
.Modifier and Type | Class and Description |
---|---|
private class |
FanoutBucket.LazyNoteBucket |
Modifier and Type | Field and Description |
---|---|
private int |
cnt
Number of non-null slots in
table . |
private static byte[] |
hexchar |
private NoteBucket[] |
table
Fan-out table similar to the PackIndex structure.
|
nonNotes, prefixLen
Constructor and Description |
---|
FanoutBucket(int prefixLen) |
Modifier and Type | Method and Description |
---|---|
(package private) InMemoryNoteBucket |
append(Note note) |
private TreeFormatter |
build(boolean insert,
ObjectInserter inserter) |
private int |
cell(AnyObjectId id) |
(package private) InMemoryNoteBucket |
contractIfTooSmall(AnyObjectId noteOn,
ObjectReader or) |
(package private) int |
estimateSize(AnyObjectId noteOn,
ObjectReader or) |
(package private) NoteBucket |
getBucket(int cell) |
(package private) Note |
getNote(AnyObjectId objId,
ObjectReader or) |
(package private) ObjectId |
getTreeId() |
(package private) java.util.Iterator<Note> |
iterator(AnyObjectId objId,
ObjectReader reader) |
(package private) static InMemoryNoteBucket |
loadIfLazy(NoteBucket b,
AnyObjectId prefix,
ObjectReader or) |
(package private) InMemoryNoteBucket |
set(AnyObjectId noteOn,
AnyObjectId noteData,
ObjectReader or) |
(package private) void |
setBucket(int cell,
InMemoryNoteBucket bucket) |
(package private) void |
setBucket(int cell,
ObjectId id) |
private int |
treeSize() |
(package private) ObjectId |
writeTree(ObjectInserter inserter) |
private final NoteBucket[] table
table[ objectId.getByte( prefixLen / 2 ) ]
. If the slot is null
there are no notes with that prefix.private int cnt
table
.private static final byte[] hexchar
void setBucket(int cell, ObjectId id)
void setBucket(int cell, InMemoryNoteBucket bucket)
Note getNote(AnyObjectId objId, ObjectReader or) throws java.io.IOException
getNote
in class NoteBucket
java.io.IOException
NoteBucket getBucket(int cell)
static InMemoryNoteBucket loadIfLazy(NoteBucket b, AnyObjectId prefix, ObjectReader or) throws java.io.IOException
java.io.IOException
java.util.Iterator<Note> iterator(AnyObjectId objId, ObjectReader reader) throws java.io.IOException
iterator
in class NoteBucket
java.io.IOException
int estimateSize(AnyObjectId noteOn, ObjectReader or) throws java.io.IOException
estimateSize
in class NoteBucket
java.io.IOException
InMemoryNoteBucket set(AnyObjectId noteOn, AnyObjectId noteData, ObjectReader or) throws java.io.IOException
set
in class NoteBucket
java.io.IOException
InMemoryNoteBucket contractIfTooSmall(AnyObjectId noteOn, ObjectReader or) throws java.io.IOException
java.io.IOException
ObjectId writeTree(ObjectInserter inserter) throws java.io.IOException
writeTree
in class NoteBucket
java.io.IOException
ObjectId getTreeId()
getTreeId
in class NoteBucket
private TreeFormatter build(boolean insert, ObjectInserter inserter) throws java.io.IOException
java.io.IOException
private int treeSize()
InMemoryNoteBucket append(Note note)
append
in class InMemoryNoteBucket
private int cell(AnyObjectId id)