/**
* Load an out-of-core partition in memory.
*
* @param partitionId Partition id
*/
private void loadPartition(Integer partitionId) {
if (loadedPartition != null) {
if (loadedPartition.getId() == partitionId) {
return;
}
if (LOG.isInfoEnabled()) {
LOG.info("loadPartition: moving partition " + loadedPartition.getId() + " out of core");
}
try {
writePartition(loadedPartition);
onDiskPartitions.put(loadedPartition.getId(), loadedPartition.getVertices().size());
loadedPartition = null;
} catch (IOException e) {
throw new IllegalStateException(
"loadPartition: failed writing " + "partition " + loadedPartition.getId() + " to disk",
e);
}
}
if (LOG.isInfoEnabled()) {
LOG.info("loadPartition: loading partition " + partitionId + " in memory");
}
try {
loadedPartition = readPartition(partitionId);
} catch (IOException e) {
throw new IllegalStateException(
"loadPartition: failed reading " + "partition " + partitionId + " from disk");
}
}
/**
* Write a partition to disk.
*
* @param partition The partition object to write
* @throws java.io.IOException
*/
private void writePartition(Partition<I, V, E, M> partition) throws IOException {
File file = new File(getPartitionPath(partition.getId()));
file.getParentFile().mkdirs();
file.createNewFile();
DataOutputStream outputStream =
new DataOutputStream(new BufferedOutputStream(new FileOutputStream(file)));
for (Vertex<I, V, E, M> vertex : partition.getVertices()) {
vertex.write(outputStream);
}
outputStream.close();
}
/**
* Add a new partition without requiring a lock.
*
* @param partition Partition to be added
*/
private void addPartitionNoLock(Partition<I, V, E, M> partition) {
synchronized (inMemoryPartitions) {
if (inMemoryPartitions.size() + 1 < maxInMemoryPartitions) {
inMemoryPartitions.put(partition.getId(), partition);
return;
}
}
try {
writePartition(partition);
onDiskPartitions.put(partition.getId(), partition.getVertices().size());
} catch (IOException e) {
throw new IllegalStateException(
"addPartition: failed writing " + "partition " + partition.getId() + "to disk");
}
}
