Examples with BTreeIndex io.pravega.common.util.btree.BTreeIndex used on opensource projects

Example 1 with BTreeIndex

use of io.pravega.common.util.btree.BTreeIndex in project pravega by pravega.

the class SegmentAttributeBTreeIndex method get.

@Override
public CompletableFuture<Map<AttributeId, Long>> get(@NonNull Collection<AttributeId> keys, @NonNull Duration timeout) {
    ensureInitialized();
    if (keys.isEmpty()) {
        // Nothing to do.
        return CompletableFuture.completedFuture(Collections.emptyMap());
    }
    // Keep two lists, one of keys (in some order) and one of serialized keys (in the same order).
    val keyList = new ArrayList<AttributeId>(keys.size());
    val serializedKeys = new ArrayList<ByteArraySegment>(keys.size());
    for (AttributeId key : keys) {
        keyList.add(key);
        serializedKeys.add(this.keySerializer.serialize(key));
    }
    // segment file (see READ_RETRY Javadoc).
    return READ_RETRY.runAsync(() -> this.index.get(serializedKeys, timeout), this.executor).thenApply(entries -> {
        assert entries.size() == keys.size() : "Unexpected number of entries returned by the index search.";
        // The index search result is a list of values in the same order as the keys we passed in, so we need
        // to use the list index to match them.
        Map<AttributeId, Long> result = new HashMap<>();
        for (int i = 0; i < keyList.size(); i++) {
            ByteArraySegment v = entries.get(i);
            if (v != null) {
                // BTreeIndex will return null if a key is not present; however we exclude that from our result.
                result.put(keyList.get(i), deserializeValue(v));
            }
        }
        return result;
    }).exceptionally(this::handleIndexOperationException);
}