| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.rya.indexing.pcj.storage.accumulo; |
| |
| import static java.util.Objects.requireNonNull; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| import java.util.Map.Entry; |
| |
| import org.apache.accumulo.core.client.Scanner; |
| import org.apache.accumulo.core.data.Key; |
| import org.apache.accumulo.core.data.Value; |
| import org.apache.rya.api.utils.CloseableIterator; |
| import org.apache.rya.indexing.pcj.storage.accumulo.BindingSetConverter.BindingSetConversionException; |
| import org.eclipse.rdf4j.query.BindingSet; |
| |
| import edu.umd.cs.findbugs.annotations.DefaultAnnotation; |
| import edu.umd.cs.findbugs.annotations.NonNull; |
| |
| /** |
| * Iterates over the results of a {@link Scanner} assuming the results are |
| * binding sets that can be converted using a {@link AccumuloPcjSerializer}. |
| */ |
| @DefaultAnnotation(NonNull.class) |
| public class ScannerBindingSetIterator implements CloseableIterator<BindingSet> { |
| |
| private static final AccumuloPcjSerializer converter = new AccumuloPcjSerializer(); |
| |
| private final Scanner scanner; |
| private final Iterator<Entry<Key, Value>> accEntries; |
| private final VariableOrder varOrder; |
| |
| /** |
| * Constructs an instance of {@link ScannerBindingSetIterator}. |
| * |
| * @param scanner - The scanner whose results will be iterated over. (not null) |
| * @param varOrder - The variable order of the binding sets the scanner returns. (not null) |
| */ |
| public ScannerBindingSetIterator(final Scanner scanner, final VariableOrder varOrder) { |
| this.scanner = requireNonNull(scanner); |
| this.accEntries = scanner.iterator(); |
| this.varOrder = requireNonNull(varOrder); |
| } |
| |
| @Override |
| public boolean hasNext() { |
| return accEntries.hasNext(); |
| } |
| |
| @Override |
| public BindingSet next() { |
| final Entry<Key, Value> entry = accEntries.next(); |
| final byte[] bindingSetBytes = entry.getKey().getRow().getBytes(); |
| try { |
| return converter.convert(bindingSetBytes, varOrder); |
| } catch (final BindingSetConversionException e) { |
| throw new RuntimeException("Could not deserialize a BindingSet from Accumulo.", e); |
| } |
| } |
| |
| @Override |
| public void close() throws IOException { |
| scanner.close(); |
| } |
| } |