Package org.neo4j.gds.core.loading

Class DeltaVarLongCompressor

java.lang.Object

org.neo4j.gds.core.loading.DeltaVarLongCompressor

All Implemented Interfaces:

java.lang.AutoCloseable, AdjacencyCompressor

public final class DeltaVarLongCompressor
extends java.lang.Object
implements AdjacencyCompressor

Nested Class Summary

Nested classes/interfaces inherited from interface org.neo4j.gds.core.compress.AdjacencyCompressor

AdjacencyCompressor.ValueMapper

Method Summary

Modifier and Type	Method	Description
void	close()	Closing this compressor will release some internal data structures, making them eligible for garbage collection.
int	compress(long nodeId, byte[] targets, long[][] properties, int numberOfCompressedTargets, int compressedBytesSize, LongArrayBuffer buffer, AdjacencyCompressor.ValueMapper mapper)	Compress a list of target ids into an adjacency list.
static AdjacencyCompressorFactory	factory(java.util.function.LongSupplier nodeCountSupplier, AdjacencyListBuilderFactory<byte[],? extends AdjacencyList,long[],? extends AdjacencyProperties> adjacencyListBuilderFactory, org.neo4j.gds.PropertyMappings propertyMappings, org.neo4j.gds.core.Aggregation[] aggregations, boolean noAggregation)

Methods inherited from class java.lang.Object

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

Method Detail

factory

public static AdjacencyCompressorFactory factory(java.util.function.LongSupplier nodeCountSupplier,
                                                 AdjacencyListBuilderFactory<byte[],? extends AdjacencyList,long[],? extends AdjacencyProperties> adjacencyListBuilderFactory,
                                                 org.neo4j.gds.PropertyMappings propertyMappings,
                                                 org.neo4j.gds.core.Aggregation[] aggregations,
                                                 boolean noAggregation)

compress

public int compress(long nodeId,
                    byte[] targets,
                    long[][] properties,
                    int numberOfCompressedTargets,
                    int compressedBytesSize,
                    LongArrayBuffer buffer,
                    AdjacencyCompressor.ValueMapper mapper)

Description copied from interface: AdjacencyCompressor

Compress a list of target ids into an adjacency list. The input values are an unsorted and separately compressed list of target ids. The provided long[] must be able to hold at least numberOfCompressedTargets elements. The input values might also store properties. The properties has the number of properties in the first dimension, followed by an uncompressed long[] for each property. Those values belong to the target id that is stored at the same array index in the uncompressed target list. Implementors need to make sure to maintain that order when re-ordering the target ids. Implementors of this method can use the provided LongArrayBuffer to reuse existing allocations of a long[] or share newly created buffers with next invocations of this method. The buffer exists solely so that implementors can reduce allocations of long[]. It is not expected that the buffer contains any useful data after this method invocation. The provided targets array will not be used after this method call. Implementors will need to write the resulting target list somewhere. Where exactly is up to the implementation. The results should end up in the data that is returned by the AdjacencyCompressorFactory.build() method. The method only needs to return the degree of the compressed adjacency list. This value can be different from numberOfCompressedTargets due to possible deduplication, though it should never be larger. The return value is only used for tracking progress and reporting, it is not stored in the graph. How the degree is stored so that it can be used by the Graph is up the implementor of this method.

Specified by:

compress in interface AdjacencyCompressor

Parameters:

nodeId - The node id that is the source node for this adjacency list. The id is from the GDS internal scope, it is *not* the Neo4j ID.

targets - A list of target ids, unsorted and compressed.

properties - A nested list of property values.

numberOfCompressedTargets - The number of targets compressed in `targets`.

compressedBytesSize - The byte size of targets.

buffer - A long array that may or may not be used during the compression.

mapper - A mapper to transform values before compressing them.

Returns:

the degree of the compressed adjacency list

close

public void close()

Description copied from interface: AdjacencyCompressor

Closing this compressor will release some internal data structures, making them eligible for garbage collection. The compressor cannot be used after it has been closed.

Specified by:

close in interface AdjacencyCompressor

Specified by:

close in interface java.lang.AutoCloseable