com.bigdata.btree.raba.codec

Class MutableRabaCoder

java.lang.Object

com.bigdata.btree.raba.codec.MutableRabaCoder

All Implemented Interfaces:

IRabaCoder, Serializable

public class MutableRabaCoder
extends Object
implements IRabaCoder

This "codes" a raba as a MutableKeyBuffer or MutableValueBuffer depending on whether it represents B+Tree keys or values. This class is used by some unit tests as a convenience for establishing a baseline for the performance of ICodedRabas against the core mutable IRaba implementations actually used by Node and Leaf.

Author:

Bryan Thompson

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
MutableRabaCoder()

Method Summary

Methods

Modifier and Type	Method and Description
ICodedRaba	decode(AbstractFixedByteArrayBuffer data) Return an IRaba which can access the coded data.
AbstractFixedByteArrayBuffer	encode(IRaba raba, DataOutputBuffer buf) Encode the data.
ICodedRaba	encodeLive(IRaba raba, DataOutputBuffer buf) Encode the data, returning an ICodedRaba.
boolean	isDuplicateKeys() Return true iff this IRabaCoder supports duplicate keys.
boolean	isKeyCoder() Yes.
boolean	isValueCoder() Yes.

Methods inherited from class java.lang.Object

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

Constructor Detail

MutableRabaCoder

public MutableRabaCoder()

Method Detail

decode

public ICodedRaba decode(AbstractFixedByteArrayBuffer data)

Description copied from interface: IRabaCoder

Return an IRaba which can access the coded data. In general, implementations SHOULD NOT materialize a backing byte[][]. Instead, the implementation should access the data in place within the caller's buffer. Frequently used fields MAY be cached, but the whole point of the IRabaCoder is to minimize the in-memory footprint for the B+Tree by using a coded (aka compressed) representation of the keys and values whenever possible.

Specified by:

decode in interface IRabaCoder

Parameters:

data - The record containing the coded data.

Returns:

A view of the coded data.

encode

public AbstractFixedByteArrayBuffer encode(IRaba raba,
                                  DataOutputBuffer buf)

Description copied from interface: IRabaCoder

Encode the data.

Note: Implementations of this method are typically heavy. While it is always valid to IRabaCoder.encode(IRaba, DataOutputBuffer) an IRaba , DO NOT invoke this arbitrarily on data which may already be coded. The ICodedRaba interface will always be implemented for coded data.

Specified by:

encode in interface IRabaCoder

Parameters:

raba - The data.

buf - A buffer on which the coded data will be written.

Returns:

A slice onto the post-condition state of the caller's buffer whose view corresponds to the coded record. This may be written directly onto an output stream or the slice may be converted to an exact fit byte[].

encodeLive

public ICodedRaba encodeLive(IRaba raba,
                    DataOutputBuffer buf)

Description copied from interface: IRabaCoder

Encode the data, returning an ICodedRaba. Implementations of this method should be optimized for the very common use case where the caller requires immediate access to the coded data record. In that case, many of the IRabaCoder implementations can be optimized by passing the underlying decoding object directly into an alternative constructor for the ICodedRaba. The byte[] slice for the coded data record is available from ICodedRaba.data().

This method covers the vast major of the use cases for coding data, which is to code B+Tree keys or values for a node or leaf that has been evicted from the AbstractBTree's write retention queue. The common use case is to wrap a coded record that was read from an IRawStore. The IndexSegmentBuilder is a special case, since the coded record will not be used other than to write it on the disk.

Specified by:

encodeLive in interface IRabaCoder

isKeyCoder

public final boolean isKeyCoder()

Yes.

Specified by:

isKeyCoder in interface IRabaCoder

isValueCoder

public final boolean isValueCoder()

Yes.

Specified by:

isValueCoder in interface IRabaCoder

isDuplicateKeys

public boolean isDuplicateKeys()

Description copied from interface: IRabaCoder

Return true iff this IRabaCoder supports duplicate keys.

Specified by:

isDuplicateKeys in interface IRabaCoder

See Also:

Stochastic Results With Analytic Query Mode