org.netbeans.mdr.persistence.btreeimpl.btreeindex

Class Btree

java.lang.Object

org.netbeans.mdr.persistence.btreeimpl.btreeindex.Btree

All Implemented Interfaces:

Index, StorageClient, Streamable

Direct Known Subclasses:

MultivaluedBtree, SinglevaluedBtree

public abstract class Btree
extends java.lang.Object
implements Index, Streamable, StorageClient

Btree index implementation. This is the top of the Btree hierarchy which implements the org.netbeans.mdr.persistence.Index interface hierarchy. This abstract class and its subclasses contain the persistent state of a Btree and the public interface methods for accessing it. The main logic for searching and updating a Btree is contained in the BtreePage class.

The btreeindex package is as much as possible independent of the btreestorage implementation. However, there are a few dependencies which would need to be addressed if this code was to be used with some other storage mechanism. The main one is the need, when instantiating a that was retrieved from the repository via Btree.read(), to instantiate the specific BtreePageSource implementation that this btree will use. The MOFID class also comes from the btreestorage package, and the Converter routines from that package are used to convert integers to byte arrays and back.

Version:

1.0

Author:

Dana Bergen

Field Summary

Fields

Modifier and Type	Field and Description
protected EntryTypeInfo	dataInfo
protected int	dataLength
protected Storage.EntryType	dataType
protected boolean	hasBigKeys
protected EntryTypeInfo	keyInfo
protected Storage.EntryType	keyType
protected java.lang.String	name
protected int	pageIdLength
protected int	pageSize
protected BtreePageSource	pageSource
protected byte[]	rootPageId
protected BtreeStorage	storage
protected boolean	uniqueKeys
protected boolean	uniqueValues

Constructor Summary

Constructors

Constructor and Description
Btree()
Btree(java.lang.String name, Storage.EntryType keyType, Storage.EntryType dataType, BtreePageSource pageSource)

Method Summary

Methods

Modifier and Type	Method and Description
void	add(java.lang.Object key, java.lang.Object data) Add a new entry to the index.
protected void	beginRead()
protected void	beginWrite()
protected void	btreePut(java.lang.Object key, java.lang.Object data, byte operation, int index)
int	consistencyCheck(java.io.PrintWriter out) Check the btree for consistency, for testing and debugging.
void	dumpTree(java.io.PrintWriter out) Print the contents of the btree for debugging purposes.
protected void	endRead()
protected void	endWrite()
Storage.EntryType	getKeyType() Returns the type of keys in index.
java.lang.String	getName() Returns the unique name of the index in the Storage.
Storage.EntryType	getValueType() Returns the type of values indexed by this index.
protected void	init()
java.util.Set	keySet() Returns a set view of the keys contained in this index.
BtreePage	pageFactory() Returns the right kind of BtreePage for this btree.
void	read(java.io.InputStream inputStream) Populate this Btree from the InputStream.
boolean	remove(java.lang.Object key) Remove all entries associated with the specified key.
void	setStorage(Storage storage) Pass the object the Storage implementation.
void	write(java.io.OutputStream outputStream) Write the state of this Btree to the OutputStream.

Methods inherited from class java.lang.Object

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

Field Detail

pageSource

protected BtreePageSource pageSource

storage

protected BtreeStorage storage

keyType

protected Storage.EntryType keyType

dataType

protected Storage.EntryType dataType

name

protected java.lang.String name

keyInfo

protected EntryTypeInfo keyInfo

dataInfo

protected EntryTypeInfo dataInfo

dataLength

protected int dataLength

pageIdLength

protected int pageIdLength

pageSize

protected int pageSize

rootPageId

protected byte[] rootPageId

uniqueKeys

protected boolean uniqueKeys

uniqueValues

protected boolean uniqueValues

hasBigKeys

protected boolean hasBigKeys

Constructor Detail

Btree

public Btree(java.lang.String name,
     Storage.EntryType keyType,
     Storage.EntryType dataType,
     BtreePageSource pageSource)
      throws StorageException

Throws:

StorageException

Btree

public Btree()

Method Detail

init

protected void init()
             throws StorageException

Throws:

StorageException

write

public void write(java.io.OutputStream outputStream)
           throws StorageException

Write the state of this Btree to the OutputStream.

Specified by:

write in interface Streamable

Parameters:

outputStream - OutputStream

Throws:

StorageException

read

public void read(java.io.InputStream inputStream)
          throws StorageException

Populate this Btree from the InputStream. The Storage reference will have already been set up in setStorage.

Specified by:

read in interface Streamable

Parameters:

inputStream - InputStream

Throws:

StorageException

setStorage

public void setStorage(Storage storage)

Description copied from interface: StorageClient

Pass the object the Storage implementation. The object can use this to fetch other objects from the MDR.

Specified by:

setStorage in interface StorageClient

Parameters:

storage - the Stroage implementation which instantiated the object

getKeyType

public Storage.EntryType getKeyType()

Returns the type of keys in index.

Specified by:

getKeyType in interface Index

Returns:

Throws:

StorageException

getValueType

public Storage.EntryType getValueType()

Returns the type of values indexed by this index.

Specified by:

getValueType in interface Index

Returns:

Throws:

StorageException

getName

public java.lang.String getName()

Returns the unique name of the index in the Storage.

Specified by:

getName in interface Index

Returns:

Throws:

StorageException

keySet

public java.util.Set keySet()
                     throws StorageException

Returns a set view of the keys contained in this index. Returned set is read only and may not be modified.

Specified by:

keySet in interface Index

Returns:

keys contained in this index

Throws:

StorageException

add

public void add(java.lang.Object key,
       java.lang.Object data)
         throws StorageException

Add a new entry to the index.

Specified by:

add in interface Index

Parameters:

key - key to insert

data - data associated with key

Throws:

StorageBadRequestException - If key or data are incorrect type, or if the insert would violate the constraints of this index

StorageException - If a problem was encountered accessing storage

remove

public boolean remove(java.lang.Object key)
               throws StorageException

Remove all entries associated with the specified key.

Specified by:

remove in interface Index

Parameters:

key - key for entry to be removed

Returns:

true if a matching entry was found

Throws:

StorageException - If there was a problem reading or writing pages

pageFactory

public BtreePage pageFactory()

Returns the right kind of BtreePage for this btree.

btreePut

protected void btreePut(java.lang.Object key,
            java.lang.Object data,
            byte operation,
            int index)
                 throws StorageException

Throws:

StorageException

beginRead

protected void beginRead()

endRead

protected void endRead()

beginWrite

protected void beginWrite()

endWrite

protected void endWrite()

dumpTree

public void dumpTree(java.io.PrintWriter out)
              throws StorageException

Print the contents of the btree for debugging purposes.

Parameters:

out - PrintWriter to print btree to

Throws:

StorageException

consistencyCheck

public int consistencyCheck(java.io.PrintWriter out)
                     throws StorageException

Check the btree for consistency, for testing and debugging.

Parameters:

out - PrintWriter to print results to

Returns:

number of errors encountered

Throws:

StorageException