com.bigdata.rdf.spo

Class SPOTupleSerializer

java.lang.Object

com.bigdata.btree.DefaultTupleSerializer<SPO,SPO>

com.bigdata.rdf.spo.SPOTupleSerializer

All Implemented Interfaces:

ITupleSerializer<SPO,SPO>, IKeyBuilderFactory, Externalizable, Serializable

public class SPOTupleSerializer
extends DefaultTupleSerializer<SPO,SPO>

(De-)serializes SPOs for statement indices.

Note: the encoded key for a statement is formed from the 64-bit long term identifier for the subject, predicate, and object positions of the statement. Each statement index uses a permutation of those term identifiers, e.g., {s,p,o}, {o,s,p}, or {p,o,s}. The SPOKeyOrder identifies the specific permutation for a given index. The keys are fully decodable and are NOT stored redundantly in the tuple's value.

The tuple value encodes the StatementEnum, indicating whether the statement is {explicit, inferred, or an axiom}, and optionally the unique statement identifier.

Note: While the static methods used to decode an existing key are safe for concurrent readers, concurrent readers also form keys using #statement2Key(IV, IV, IV) and therefore require a thread-local IKeyBuilder.

Author:

Bryan Thompson

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor and Description
SPOTupleSerializer() De-serialization constructor.
SPOTupleSerializer(SPOKeyOrder keyOrder, boolean sids) Create an ITupleSerializer for the indicated access path.
SPOTupleSerializer(SPOKeyOrder keyOrder, boolean sids, IRabaCoder leafKeySer, IRabaCoder leafValSer) Create an ITupleSerializer for the indicated access path.

Method Summary

Methods

Modifier and Type	Method and Description
ISPO	decodeValue(ISPO spo, byte[] val) Set the statement type, bit flags, and optional sid based on the tuple value.
SPO	deserialize(ITuple tuple) De-serializes an object from the value stored in the tuple (ignores the key stored in the tuple).
SPO	deserializeKey(ITuple tuple) This is an unsupported operation.
SPOKeyOrder	getKeyOrder()
void	readExternal(ObjectInput in)
byte[]	serializeKey(ISPO spo) Forms the statement key.
byte[]	serializeKey(Object obj) Serialize a facet of an object's state that places the object into the total sort order for the index.
byte[]	serializeVal(boolean override, boolean userFlag, StatementEnum type) Return the byte[] that would be written into a statement index for this SPO, including the optional StatementEnum.MASK_OVERRIDE bit.
byte[]	serializeVal(ISPO spo) Variant duplicates the behavior of serializeVal(SPO) to provide support for non-SPO ISPOs.
byte[]	serializeVal(SPO spo) Encodes the StatementEnum and the optional statement identifier.
void	writeExternal(ObjectOutput out)

Methods inherited from class com.bigdata.btree.DefaultTupleSerializer

getDefaultKeyBuilderFactory, getDefaultLeafKeysCoder, getDefaultValuesCoder, getKeyBuilder, getLeafKeysCoder, getLeafValuesCoder, getPrimaryKeyBuilder, newInstance, setLeafKeysCoder, setLeafValuesCoder, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

SPOTupleSerializer

public SPOTupleSerializer()

De-serialization constructor.

SPOTupleSerializer

public SPOTupleSerializer(SPOKeyOrder keyOrder,
                  boolean sids)

Create an ITupleSerializer for the indicated access path.

Parameters:

keyOrder - The access path.

SPOTupleSerializer

public SPOTupleSerializer(SPOKeyOrder keyOrder,
                  boolean sids,
                  IRabaCoder leafKeySer,
                  IRabaCoder leafValSer)

Create an ITupleSerializer for the indicated access path.

Parameters:

keyOrder - The access path.

sids - If true, attach sids to decoded SPOs where appropriate.

leafKeySer -

leafValSer -

Method Detail

getKeyOrder

public SPOKeyOrder getKeyOrder()

serializeKey

public byte[] serializeKey(Object obj)

Description copied from interface: ITupleSerializer

Serialize a facet of an object's state that places the object into the total sort order for the index. This method is automatically applied by IAutoboxBTree.insert(Object, Object) and friends to convert the key object into an unsigned variable length byte[].

Note: This handles the conversion between an object and the unsigned variable length byte[] representation of that object which determines its place within the total index order. Since this transform imposes the total order of the index, different techniques are applied here than are applied to the serialization of the index values.

Specified by:

serializeKey in interface ITupleSerializer<SPO,SPO>

Overrides:

serializeKey in class DefaultTupleSerializer<SPO,SPO>

Parameters:

obj - A object (MAY NOT be null).

Returns:

An unsigned byte[] which places the object into the total sort order for the index and never null ( null keys are not allowed into an index).

serializeKey

public byte[] serializeKey(ISPO spo)

Forms the statement key.

Parameters:

spo - The statement.

Returns:

The key.

serializeVal

public byte[] serializeVal(ISPO spo)

Variant duplicates the behavior of serializeVal(SPO) to provide support for non-SPO ISPOs.

serializeVal

public byte[] serializeVal(SPO spo)

Encodes the StatementEnum and the optional statement identifier.

Specified by:

serializeVal in interface ITupleSerializer<SPO,SPO>

Overrides:

serializeVal in class DefaultTupleSerializer<SPO,SPO>

Parameters:

spo - The object to be serialized (MAY be null).

Returns:

The serialized representation of the object as a byte[] -or- null if the reference is null.

serializeVal

public byte[] serializeVal(boolean override,
                  boolean userFlag,
                  StatementEnum type)

Return the byte[] that would be written into a statement index for this SPO, including the optional StatementEnum.MASK_OVERRIDE bit. If the statement identifier is non-null then it will be included in the returned byte[].

Parameters:

override - true iff you want the StatementEnum.MASK_OVERRIDE bit set (this is only set when serializing values for a remote procedure that will write on the index, it is never set in the index itself).

userFlag - true iff you want the StatementEnum.MASK_USER_FLAG bit set.

type - The StatementEnum.

Returns:

The value that would be written into a statement index for this SPO.

deserialize

public SPO deserialize(ITuple tuple)

Description copied from class: DefaultTupleSerializer

De-serializes an object from the value stored in the tuple (ignores the key stored in the tuple).

Specified by:

deserialize in interface ITupleSerializer<SPO,SPO>

Overrides:

deserialize in class DefaultTupleSerializer<SPO,SPO>

Parameters:

tuple - The tuple.

Returns:

The de-serialized object.

deserializeKey

public SPO deserializeKey(ITuple tuple)

Description copied from class: DefaultTupleSerializer

This is an unsupported operation. Additional information is required to either decode the internal unsigned byte[] keys or to extract the key from the de-serialized value (if it is being stored in that value). You can either write your own ITupleSerializer or you can specialize this one so that it can de-serialize your keys using whichever approach makes the most sense for your data.

Specified by:

deserializeKey in interface ITupleSerializer<SPO,SPO>

Overrides:

deserializeKey in class DefaultTupleSerializer<SPO,SPO>

decodeValue

public ISPO decodeValue(ISPO spo,
               byte[] val)

Set the statement type, bit flags, and optional sid based on the tuple value.

readExternal

public void readExternal(ObjectInput in)
                  throws IOException,
                         ClassNotFoundException

Specified by:

readExternal in interface Externalizable

Overrides:

readExternal in class DefaultTupleSerializer<SPO,SPO>

Throws:

IOException

ClassNotFoundException

writeExternal

public void writeExternal(ObjectOutput out)
                   throws IOException

Specified by:

writeExternal in interface Externalizable

Overrides:

writeExternal in class DefaultTupleSerializer<SPO,SPO>

Throws:

IOException