diff --git a/java/server/src/main/java/org/softwareheritage/graph/Graph.java b/java/server/src/main/java/org/softwareheritage/graph/Graph.java
index 183b1e4..1221984 100644
--- a/java/server/src/main/java/org/softwareheritage/graph/Graph.java
+++ b/java/server/src/main/java/org/softwareheritage/graph/Graph.java
@@ -1,217 +1,227 @@
package org.softwareheritage.graph;
import java.io.IOException;
import it.unimi.dsi.big.webgraph.BVGraph;
import it.unimi.dsi.lang.FlyweightPrototype;
import it.unimi.dsi.big.webgraph.LazyLongIterator;
import org.softwareheritage.graph.Node;
import org.softwareheritage.graph.SwhPID;
import org.softwareheritage.graph.backend.NodeIdMap;
import org.softwareheritage.graph.backend.NodeTypesMap;
/**
* Main class storing the compressed graph and node id mappings.
*
* The compressed graph is stored using the WebGraph
* ecosystem. Additional mappings are necessary because Software Heritage uses string based persistent
* identifiers (PID) while WebGraph uses integers internally. These two mappings (long id ↔
* PID) are used for the input (users refer to the graph using PID) and the output (convert back to
* PID for users results). However, since graph traversal can be restricted depending on the node
* type (see {@link AllowedEdges}), a long id → node type map is stored as well to avoid a full
* PID lookup.
*
* @author The Software Heritage developers
* @see org.softwareheritage.graph.AllowedEdges
* @see org.softwareheritage.graph.backend.NodeIdMap
* @see org.softwareheritage.graph.backend.NodeTypesMap
*/
public class Graph implements FlyweightPrototype {
/** File extension for the SWH PID to long node id map */
public static final String PID_TO_NODE = ".pid2node.csv";
/** File extension for the long node id to SWH PID map */
public static final String NODE_TO_PID = ".node2pid.csv";
/** File extension for the long node id to node typ map */
public static final String NODE_TO_TYPE = ".node2type.map";
/** Compressed graph stored as a {@link it.unimi.dsi.big.webgraph.BVGraph} */
BVGraph graph;
/** Transposed compressed graph (used for backward traversals) */
BVGraph graphTransposed;
/** Path and basename of the compressed graph */
String path;
/** Mapping long id ↔ SWH PIDs */
NodeIdMap nodeIdMap;
/** Mapping long id → node types */
NodeTypesMap nodeTypesMap;
/**
* Constructor.
*
* @param path path and basename of the compressed graph to load
*/
public Graph(String path) throws IOException {
this.graph = BVGraph.load(path);
this.graphTransposed = BVGraph.load(path + "-transposed");
this.path = path;
this.nodeTypesMap = new NodeTypesMap(path);
// TODO: we don't need to load the nodeIdMap now that all the
// translation between ints and PIDs is happening on the Python side.
// However, some parts of the code still depend on this, so it's
// commented out while we decide on what to do with it.
this.nodeIdMap = null; // new NodeIdMap(path, getNbNodes());
}
// Protected empty constructor to implement copy()
protected Graph() { }
/**
* Return a flyweight copy of the graph.
*/
@Override
public Graph copy() {
final Graph ng = new Graph();
ng.graph = this.graph.copy();
ng.graphTransposed = this.graphTransposed.copy();
ng.path = path;
ng.nodeIdMap = this.nodeIdMap;
ng.nodeTypesMap = this.nodeTypesMap;
return ng;
}
/**
* Cleans up graph resources after use.
*/
public void cleanUp() throws IOException {
nodeIdMap.close();
}
/**
* Returns the graph full path.
*
* @return graph full path
*/
public String getPath() {
return path;
}
/**
* Converts {@link SwhPID} node to long.
*
* @param swhPID node specified as a {@link SwhPID}
* @return internal long node id
* @see org.softwareheritage.graph.SwhPID
*/
public long getNodeId(SwhPID swhPID) {
return nodeIdMap.getNodeId(swhPID);
}
/**
* Converts long id node to {@link SwhPID}.
*
* @param nodeId node specified as a long id
* @return external SWH PID
* @see org.softwareheritage.graph.SwhPID
*/
public SwhPID getSwhPID(long nodeId) {
return nodeIdMap.getSwhPID(nodeId);
}
/**
* Returns node type.
*
* @param nodeId node specified as a long id
* @return corresponding node type
* @see org.softwareheritage.graph.Node.Type
*/
public Node.Type getNodeType(long nodeId) {
return nodeTypesMap.getType(nodeId);
}
/**
* Returns number of nodes in the graph.
*
* @return number of nodes in the graph
*/
public long getNbNodes() {
return graph.numNodes();
}
/**
* Returns number of edges in the graph.
*
* @return number of edges in the graph
*/
public long getNbEdges() {
return graph.numArcs();
}
/**
* Returns lazy iterator of successors of a node.
*
* @param nodeId node specified as a long id
* @return lazy iterator of successors of the node, specified as a WebGraph LazyLongIterator
*/
public LazyLongIterator successors(long nodeId) {
return graph.successors(nodeId);
}
/**
* Returns the outdegree of a node.
*
* @param nodeId node specified as a long id
* @return outdegree of a node
*/
public long outdegree(long nodeId) {
return graph.outdegree(nodeId);
}
/**
* Returns lazy iterator of predecessors of a node.
*
* @param nodeId node specified as a long id
* @return lazy iterator of predecessors of the node, specified as a WebGraph LazyLongIterator
*/
public LazyLongIterator predecessors(long nodeId) {
return graphTransposed.successors(nodeId);
}
/**
* Returns the indegree of a node.
*
* @param nodeId node specified as a long id
* @return indegree of a node
*/
public long indegree(long nodeId) {
return graphTransposed.outdegree(nodeId);
}
/**
* Returns the degree of a node, depending on graph orientation.
*
* @param nodeId node specified as a long id
* @param useTransposed boolean value to use transposed graph
* @return degree of a node
*/
public long degree(long nodeId, boolean useTransposed) {
return (useTransposed) ? indegree(nodeId) : outdegree(nodeId);
}
/**
* Returns the neighbors of a node (as a lazy iterator), depending on graph orientation.
*
* @param nodeId node specified as a long id
* @param useTransposed boolean value to use transposed graph
* @return lazy iterator of neighbors of the node, specified as a WebGraph LazyLongIterator
*/
public LazyLongIterator neighbors(long nodeId, boolean useTransposed) {
return (useTransposed) ? predecessors(nodeId) : successors(nodeId);
}
+
+ /**
+ * Returns the underlying BVGraph.
+ *
+ * @param useTransposed boolean value to use transposed graph
+ * @return WebGraph BVGraph
+ */
+ public BVGraph getBVGraph(boolean useTransposed) {
+ return (useTransposed) ? this.graphTransposed : this.graph;
+ }
}