/*
* 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.tinkerpop.gremlin.hadoop.structure.HadoopGraph;
import org.apache.tinkerpop.gremlin.hadoop.structure.HadoopVertex;
import org.apache.tinkerpop.gremlin.process.traversal.util.FastNoSuchElementException;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import java.io.IOException;
/**
* @author Marko A. Rodriguez (http://markorodriguez.com)
*/
public final class HadoopVertexIterator extends HadoopElementIterator<Vertex> {
private HadoopVertex nextVertex = null;
public HadoopVertexIterator(final HadoopGraph graph) throws IOException {
super(graph);
}
@Override
public Vertex next() {
try {
if (this.nextVertex != null) {
final Vertex temp = this.nextVertex;
this.nextVertex = null;
return temp;
} else {
while (!this.readers.isEmpty()) {
if (this.readers.peek().nextKeyValue())
return new HadoopVertex(this.readers.peek().getCurrentValue().get(), this.graph);
else
this.readers.remove().close();
}
}
throw FastNoSuchElementException.instance();
} catch (final Exception e) {
throw new IllegalStateException(e.getMessage(), e);
}
}
@Override
public boolean hasNext() {
try {
if (null != this.nextVertex) return true;
else {
while (!this.readers.isEmpty()) {
if (this.readers.peek().nextKeyValue()) {
this.nextVertex = new HadoopVertex(this.readers.peek().getCurrentValue().get(), this.graph);
return true;
} else
this.readers.remove().close();
}
}
} catch (final Exception e) {
throw new IllegalStateException(e.getMessage(), e);
}
return false;
}
}