Package com.sun.electric.database.geometry.btree

A B+Tree with many features.

See:
Description

Class Summary

BTree<K extends Serializable & Comparable,V extends Serializable,S extends Serializable>	A B+Tree implemented using PageStorage.
BTreeTest	A simple regression test for the BTree.
CachingPageStorage	API for a PageStorage with some sort of cache; the CachingPageStorage.CachedPage class provides an interface for interacting with the cache.
CachingPageStorageWrapper	A wrapper around PageStorage that makes it a CachingPageStorage.
FilePageStorage	PageStorage implemented via a RandomAccessFile.
MemoryPageStorage	A PageStorage that uses plain old memory.
OverflowPageStorage	Combines two PageStorage objects, using the first until the "high water mark" is exceeded, then moving to the other.
PageStorage	Stores and retrieves fixed-size byte sequences indexed by a page number; page numbers are guaranteed to be contiguous starting at zero.

Package com.sun.electric.database.geometry.btree Description

A B+Tree with many features.

At the moment, the on-disk format is NOT stable. It will almost certainly change in the future. Please do not use the BTree to store data across invocations of the JVM.

At the moment, the BTree does not support deleting or replacing values.

There are three kinds of classes in this package:

• The BTree class itself, which provides the B+Tree data structure parameterized over a key type (K), value type (V), and optional summary (see below) type (S).
• Subclasses of NodeCursor, which are package-private. These act like smart "pointers" to individual pages within the BTree and help to simplify BTree.java.
• The PageStorage class and subclasses. A PageStorage is sort of like a HashMap<Integer,byte[]> with a few extra features and restrictions. A CachingPageStorage is like a PageStorage that lets you write directly to the byte[]'s that are resident in memory.

The subpackage unboxed provides "unboxed" versions of many data structures; please take a brief look at it first.