org.eclipse.jgit.notes

Class FanoutBucket

java.lang.Object

org.eclipse.jgit.notes.NoteBucket

org.eclipse.jgit.notes.InMemoryNoteBucket

org.eclipse.jgit.notes.FanoutBucket

class FanoutBucket
extends InMemoryNoteBucket

A note tree holding only note subtrees, each named using a 2 digit hex name. The fanout buckets/trees contain on average 256 subtrees, naming the subtrees by a slice of the ObjectId contained within them, from "00" through "ff". Each fanout bucket has a 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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private class	FanoutBucket.LazyNoteBucket

Field Summary

Fields

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.

Fields inherited from class org.eclipse.jgit.notes.InMemoryNoteBucket

nonNotes, prefixLen

Constructor Summary

Constructors

Constructor and Description
FanoutBucket(int prefixLen)

Method Summary

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)

Methods inherited from class java.lang.Object

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

Field Detail

table

private final NoteBucket[] table

Fan-out table similar to the PackIndex structure. Notes for an object are stored within the sub-bucket that is held here as table[ objectId.getByte( prefixLen / 2 ) ]. If the slot is null there are no notes with that prefix.

cnt

private int cnt

Number of non-null slots in table.

hexchar

private static final byte[] hexchar

Constructor Detail

FanoutBucket

FanoutBucket(int prefixLen)

Method Detail

setBucket

void setBucket(int cell,
               ObjectId id)

setBucket

void setBucket(int cell,
               InMemoryNoteBucket bucket)

getNote

Note getNote(AnyObjectId objId,
             ObjectReader or)
      throws java.io.IOException

Specified by:

getNote in class NoteBucket

Throws:

java.io.IOException

getBucket

NoteBucket getBucket(int cell)

loadIfLazy

static InMemoryNoteBucket loadIfLazy(NoteBucket b,
                                     AnyObjectId prefix,
                                     ObjectReader or)
                              throws java.io.IOException

Throws:

java.io.IOException

iterator

java.util.Iterator<Note> iterator(AnyObjectId objId,
                                  ObjectReader reader)
                           throws java.io.IOException

Specified by:

iterator in class NoteBucket

Throws:

java.io.IOException

estimateSize

int estimateSize(AnyObjectId noteOn,
                 ObjectReader or)
          throws java.io.IOException

Specified by:

estimateSize in class NoteBucket

Throws:

java.io.IOException

set

InMemoryNoteBucket set(AnyObjectId noteOn,
                       AnyObjectId noteData,
                       ObjectReader or)
                throws java.io.IOException

Specified by:

set in class NoteBucket

Throws:

java.io.IOException

contractIfTooSmall

InMemoryNoteBucket contractIfTooSmall(AnyObjectId noteOn,
                                      ObjectReader or)
                               throws java.io.IOException

Throws:

java.io.IOException

writeTree

ObjectId writeTree(ObjectInserter inserter)
            throws java.io.IOException

Specified by:

writeTree in class NoteBucket

Throws:

java.io.IOException

getTreeId

ObjectId getTreeId()

Specified by:

getTreeId in class NoteBucket

build

private TreeFormatter build(boolean insert,
                            ObjectInserter inserter)
                     throws java.io.IOException

Throws:

java.io.IOException

treeSize

private int treeSize()

append

InMemoryNoteBucket append(Note note)

Specified by:

append in class InMemoryNoteBucket

cell

private int cell(AnyObjectId id)