| /* |
| * 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.tinkerpop.gremlin.hadoop.structure.io; |
| |
| import org.apache.hadoop.conf.Configuration; |
| import org.apache.hadoop.fs.FileStatus; |
| import org.apache.hadoop.fs.FileSystem; |
| import org.apache.hadoop.fs.Path; |
| import org.apache.hadoop.io.SequenceFile; |
| import org.apache.tinkerpop.gremlin.process.computer.KeyValue; |
| import org.apache.tinkerpop.gremlin.process.traversal.util.FastNoSuchElementException; |
| |
| import java.io.IOException; |
| import java.util.Iterator; |
| import java.util.LinkedList; |
| import java.util.Queue; |
| |
| /** |
| * @author Marko A. Rodriguez (http://markorodriguez.com) |
| */ |
| public final class ObjectWritableIterator implements Iterator<KeyValue> { |
| |
| private final ObjectWritable key = new ObjectWritable(); |
| private final ObjectWritable value = new ObjectWritable(); |
| private boolean available = false; |
| private final Queue<SequenceFile.Reader> readers = new LinkedList<>(); |
| |
| public ObjectWritableIterator(final Configuration configuration, final Path path) throws IOException { |
| for (final FileStatus status : FileSystem.get(configuration).listStatus(path, HiddenFileFilter.instance())) { |
| this.readers.add(new SequenceFile.Reader(configuration, SequenceFile.Reader.file(status.getPath()))); |
| } |
| } |
| |
| @Override |
| public boolean hasNext() { |
| try { |
| if (this.available) { |
| return true; |
| } else { |
| while (true) { |
| if (this.readers.isEmpty()) |
| return false; |
| if (this.readers.peek().next(this.key, this.value)) { |
| this.available = true; |
| return true; |
| } else |
| this.readers.remove().close(); |
| } |
| } |
| } catch (final IOException e) { |
| throw new IllegalStateException(e.getMessage(), e); |
| } |
| } |
| |
| @Override |
| public KeyValue next() { |
| try { |
| if (this.available) { |
| this.available = false; |
| return new KeyValue<>(this.key.get(), this.value.get()); |
| } else { |
| while (true) { |
| if (this.readers.isEmpty()) |
| throw FastNoSuchElementException.instance(); |
| if (this.readers.peek().next(this.key, this.value)) { |
| return new KeyValue<>(this.key.get(), this.value.get()); |
| } else |
| this.readers.remove().close(); |
| } |
| } |
| } catch (final IOException e) { |
| throw new IllegalStateException(e.getMessage(), e); |
| } |
| } |
| } |