AstyanaxStorageProvider.java 文件源码

private Iterator<Map.Entry<String, StorageSummary>> decodeMetadataRows(
        final Iterator<Row<ByteBuffer, Composite>> rowIter, final AstyanaxTable table) {
    return new AbstractIterator<Map.Entry<String, StorageSummary>>() {
        @Override
        protected Map.Entry<String, StorageSummary> computeNext() {
            while (rowIter.hasNext()) {
                Row<ByteBuffer, Composite> row = rowIter.next();
                ByteBuffer key = row.getKey();
                ColumnList<Composite> columns = row.getColumns();

                String blobId = AstyanaxStorage.getContentKey(key);

                StorageSummary summary = toStorageSummary(columns);
                if (summary == null) {
                    continue;  // Partial blob, parts may still be replicating.
                }

                // Cleanup older versions of the blob, if any (unlikely).
                deleteOldColumns(table, blobId, columns, summary.getTimestamp());

                return Maps.immutableEntry(blobId, summary);
            }
            return endOfData();
        }
    };
}