org.janusgraph.graphdb.olap

Class VertexJobConverter

java.lang.Object

org.janusgraph.graphdb.olap.AbstractScanJob

org.janusgraph.graphdb.olap.VertexJobConverter

All Implemented Interfaces:

Cloneable, ScanJob

Direct Known Subclasses:

VertexMapJob.Executor, VertexProgramScanJob.Executor

public class VertexJobConverter
extends AbstractScanJob

Author:

Matthias Broecheler ([email protected])

Field Summary

Fields

Modifier and Type	Field and Description
static String	GHOST_VERTEX_COUNT
protected VertexScanJob	job
static String	TRUNCATED_ENTRY_LISTS Number of result sets that got (possibly) truncated due to an applied query limit
protected static SliceQuery	VERTEX_EXISTS_QUERY

Fields inherited from class org.janusgraph.graphdb.olap.AbstractScanJob

graph, tx

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	VertexJobConverter(JanusGraph graph, VertexScanJob job)
protected	VertexJobConverter(VertexJobConverter copy)

Method Summary

Modifier and Type	Method and Description
VertexJobConverter	clone() Returns a clone of this ScanJob.
static ScanJob	convert(JanusGraph graph, VertexScanJob vertexJob)
static ScanJob	convert(VertexScanJob vertexJob)
Predicate<StaticBuffer>	getKeyFilter() A predicate that determines whether ScanJob.process(org.janusgraph.diskstorage.StaticBuffer, java.util.Map, ScanMetrics) should be invoked for the given key.
List<SliceQuery>	getQueries() Returns one or more SliceQuery instances belonging to this ScanJob.
void	process(StaticBuffer key, Map<SliceQuery,EntryList> entries, ScanMetrics metrics) Run this ScanJob's computation on the supplied row-key and entries.
protected StandardJanusGraphTx	startTransaction(StandardJanusGraph graph)
void	workerIterationEnd(ScanMetrics metrics) Invoked after a block of computation (i.e.
void	workerIterationStart(Configuration jobConfig, Configuration graphConfig, ScanMetrics metrics) Invoked before a block of computation (i.e.

Methods inherited from class org.janusgraph.graphdb.olap.AbstractScanJob

close, getVertexId, isGhostVertex, open

Methods inherited from class java.lang.Object

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

Field Detail

VERTEX_EXISTS_QUERY

protected static final SliceQuery VERTEX_EXISTS_QUERY

GHOST_VERTEX_COUNT

public static final String GHOST_VERTEX_COUNT

See Also:

Constant Field Values

TRUNCATED_ENTRY_LISTS

public static final String TRUNCATED_ENTRY_LISTS

Number of result sets that got (possibly) truncated due to an applied query limit

See Also:

Constant Field Values

job

protected final VertexScanJob job

Constructor Detail

VertexJobConverter

protected VertexJobConverter(JanusGraph graph,
                             VertexScanJob job)

VertexJobConverter

protected VertexJobConverter(VertexJobConverter copy)

Method Detail

convert

public static ScanJob convert(JanusGraph graph,
                              VertexScanJob vertexJob)

convert

public static ScanJob convert(VertexScanJob vertexJob)

workerIterationStart

public void workerIterationStart(Configuration jobConfig,
                                 Configuration graphConfig,
                                 ScanMetrics metrics)

Description copied from interface: ScanJob

Invoked before a block of computation (i.e. multiple process() calls) is handed to this particular ScanJob. Can be used to initialize the iteration. This method is called exactly once for each before a block of computation. This method is semantically aligned with VertexProgram.workerIterationStart(Memory) This method may not be called if there is no data to be processed. Correspondingly, the end method won't be called either. No-op default implementation.

Parameters:

jobConfig - configuration for this particular job

graphConfig - configuration options for the entire graph against which this job is executed

metrics - ScanMetrics for this job

startTransaction

protected StandardJanusGraphTx startTransaction(StandardJanusGraph graph)

Specified by:

startTransaction in class AbstractScanJob

workerIterationEnd

public void workerIterationEnd(ScanMetrics metrics)

Description copied from interface: ScanJob

Invoked after a block of computation (i.e. multiple process() calls) is handed to this particular ScanJob. Can be used to close any resources held by this job. This method is called exactly once for each after a block of computation. This method is semantically aligned with VertexProgram.workerIterationEnd(Memory) This method may not be called if there is no data to be processed. Correspondingly, the start method won't be called either. No-op default implementation.

Parameters:

metrics - ScanMetrics for this job

process

public void process(StaticBuffer key,
                    Map<SliceQuery,EntryList> entries,
                    ScanMetrics metrics)

Description copied from interface: ScanJob

Run this ScanJob's computation on the supplied row-key and entries.

This method will be called by a client of this interface if and only if both of the following criteria are satisfied:

• The predicate returned by ScanJob.getKeyFilter() must evaluate to true on the key.
• The entries parameter must contain an entry whose key is the first SliceQuery returned by ScanJob.getQueries() and whose value is an EntryList with at least size one. In other words, the initial query in this job's query list must have matched at least once.

Implementations may assume these two conditions are satisfied. Calling this method when either of these two conditions is false yields undefined behavior.

It is the caller's responsibility to construct an entries map that maps each SliceQuery to that query's matches. The caller is also responsible for truncating the entries values to honor BaseQuery.getLimit() when BaseQuery.hasLimit() is true. Passing in an entries value longer than the limit set in its respective key yields undefined behavior.

This method may be called by concurrent threads in a single process.

getQueries

public List<SliceQuery> getQueries()

Description copied from interface: ScanJob

Returns one or more SliceQuery instances belonging to this ScanJob.

Before calling ScanJob.process(org.janusgraph.diskstorage.StaticBuffer, java.util.Map, ScanMetrics), users of this interface must check that the key in question contains at least one entry matching the initial SliceQuery returned by this method. See the javadoc for the process method for more information.

If this method returns more than one query, then the initial query's lower bound must be all zero bits and the initial query's upper bound must be all one bits (per the preconditions in StandardScannerExecutor, the reference ScanJob executor).

Returns:

one or more queries

getKeyFilter

public Predicate<StaticBuffer> getKeyFilter()

Description copied from interface: ScanJob

A predicate that determines whether ScanJob.process(org.janusgraph.diskstorage.StaticBuffer, java.util.Map, ScanMetrics) should be invoked for the given key. If the predicate returns true, then users of this interface should invoke process for the key and its associated entries. If the predicate returns false, then users of this interface need not invoke process for the key and its associated entries.

This is essentially an optimization that lets implementations of this interface signal to client code that a row can be safely skipped without affecting the execution of this ScanJob.

The returned predicate may be called by concurrent threads in a single process.

Returns:

a threadsafe predicate for edgestore keys

clone

public VertexJobConverter clone()

Description copied from interface: ScanJob

Returns a clone of this ScanJob. The clone will not yet be initialized for computation but all of its internal state (if any) must match that of the original copy.

Specified by:

clone in interface ScanJob

Specified by:

clone in class AbstractScanJob

Returns:

A clone of this ScanJob