com.sleepycat.je.tree

Class ChildReference

java.lang.Object

com.sleepycat.je.tree.ChildReference

All Implemented Interfaces:

Loggable

public class ChildReference
extends Object
implements Loggable

A ChildReference is a reference in the tree from parent to child. It contains a node reference, key, and LSN.

Constructor Summary

Constructors

Constructor and Description
ChildReference() Construct an empty child reference, for reading from the log.
ChildReference(Node target, byte[] key, long lsn) Construct a ChildReference for inserting a new entry.
ChildReference(Node target, byte[] key, long lsn, byte existingState) Construct a ChildReference for inserting an existing entry.

Method Summary

Modifier and Type	Method and Description
void	clearTarget() Clear the target for this ChildReference.
void	dumpLog(StringBuilder sb, boolean verbose) Write the object into the string buffer for log dumping.
String	dumpString(int nspaces, boolean dumpTags)
Node	fetchTarget(DatabaseImpl database, IN parent) Fetch the target object that this ChildReference refers to.
byte[]	getKey() Return the key for this ChildReference.
int	getLogSize()
long	getLsn() Return the LSN for this ChildReference.
Node	getTarget() Return the target for this ChildReference.
long	getTransactionId()
boolean	isKnownDeleted()
boolean	logicalEquals(Loggable other)
void	readFromLog(ByteBuffer itemBuffer, int entryVersion) Initialize this object from the data in itemBuf.
void	setKey(byte[] key) Set the key for this ChildReference.
void	setLsn(long lsn) Sets the target LSN for this ChildReference.
void	setTarget(Node target) Sets the target for this ChildReference.
String	toString()
void	writeToLog(ByteBuffer logBuffer) Serialize this object into the buffer.

Methods inherited from class java.lang.Object

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

Constructor Detail

ChildReference

public ChildReference()

Construct an empty child reference, for reading from the log.

ChildReference

public ChildReference(Node target,
                      byte[] key,
                      long lsn)

Construct a ChildReference for inserting a new entry.

ChildReference

public ChildReference(Node target,
                      byte[] key,
                      long lsn,
                      byte existingState)

Construct a ChildReference for inserting an existing entry.

Method Detail

getKey

public byte[] getKey()

Return the key for this ChildReference.

setKey

public void setKey(byte[] key)

Set the key for this ChildReference.

fetchTarget

public Node fetchTarget(DatabaseImpl database,
                        IN parent)
                 throws DatabaseException

Fetch the target object that this ChildReference refers to. If the object is already in VM, then just return the reference to it. If the object is not in VM, then read the object from the log. If the object has been faulted in and the in arg is supplied, then the total memory size cache in the IN is invalidated.

Parameters:

database - The database that this ChildReference resides in.

parent - The IN that this ChildReference lives in. If the target is fetched (i.e. it is null on entry), then the total in memory count is invalidated in the IN. May be null. For example, the root is a ChildReference and there is no parent IN when the rootIN is fetched in.

Returns:

the Node object representing the target node in the tree, or null if there is no target of this ChildReference, or null if a pendingDelete or knownDeleted entry has been cleaned.

Throws:

DatabaseException

getTarget

public Node getTarget()

Return the target for this ChildReference.

setTarget

public void setTarget(Node target)

Sets the target for this ChildReference. No need to make dirty, that state only applies to key and LSN.

clearTarget

public void clearTarget()

Clear the target for this ChildReference. No need to make dirty, that state only applies to key and LSN. This method is public because it's safe and used by RecoveryManager. This can't corrupt the tree.

getLsn

public long getLsn()

Return the LSN for this ChildReference.

Returns:

the LSN for this ChildReference.

setLsn

public void setLsn(long lsn)

Sets the target LSN for this ChildReference.

Parameters:

lsn - the target LSN.

isKnownDeleted

public boolean isKnownDeleted()

Returns:

true if entry is deleted for sure.

getLogSize

public int getLogSize()

Specified by:

getLogSize in interface Loggable

Returns:

number of bytes used to store this object.

See Also:

Loggable.getLogSize()

writeToLog

public void writeToLog(ByteBuffer logBuffer)

Description copied from interface: Loggable

Serialize this object into the buffer.

Specified by:

writeToLog in interface Loggable

Parameters:

logBuffer - is the destination buffer

See Also:

Loggable.writeToLog(java.nio.ByteBuffer)

readFromLog

public void readFromLog(ByteBuffer itemBuffer,
                        int entryVersion)

Description copied from interface: Loggable

Initialize this object from the data in itemBuf.

Specified by:

readFromLog in interface Loggable

Parameters:

itemBuffer - the source buffer

entryVersion - the log version of the data

See Also:

Loggable.readFromLog(java.nio.ByteBuffer, int)

dumpLog

public void dumpLog(StringBuilder sb,
                    boolean verbose)

Description copied from interface: Loggable

Write the object into the string buffer for log dumping. Each object should be dumped without indentation or new lines and should be valid XML.

Specified by:

dumpLog in interface Loggable

Parameters:

sb - destination string buffer

verbose - if true, dump the full, verbose version

See Also:

Loggable.dumpLog(java.lang.StringBuilder, boolean)

getTransactionId

public long getTransactionId()

Specified by:

getTransactionId in interface Loggable

Returns:

the transaction id embedded within this loggable object. Objects that have no transaction id should return 0.

See Also:

Loggable.getTransactionId()

logicalEquals

public boolean logicalEquals(Loggable other)

Specified by:

logicalEquals in interface Loggable

Returns:

true if these two loggable items are logically the same. Used for replication testing.

See Also:

Always return false, this item should never be compared.

dumpString

public String dumpString(int nspaces,
                         boolean dumpTags)

toString

public String toString()

Overrides:

toString in class Object