/*
* 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.flink.storm.util;
import org.apache.storm.spout.SpoutOutputCollector;
import org.apache.storm.task.TopologyContext;
import org.apache.storm.tuple.Values;
import java.io.IOException;
import java.util.Map;
/**
* Implements a Spout that reads data from a given local file. The spout stops automatically
* when it reached the end of the file.
*/
public class FiniteFileSpout extends FileSpout implements FiniteSpout {
private static final long serialVersionUID = -1472978008607215864L;
private String line;
private boolean newLineRead;
public FiniteFileSpout() {}
public FiniteFileSpout(String path) {
super(path);
}
@SuppressWarnings("rawtypes")
@Override
public void open(final Map conf, final TopologyContext context, final SpoutOutputCollector collector) {
super.open(conf, context, collector);
newLineRead = false;
}
@Override
public void nextTuple() {
this.collector.emit(new Values(line));
newLineRead = false;
}
/**
* Can be called before nextTuple() any times including 0.
*/
@Override
public boolean reachedEnd() {
try {
readLine();
} catch (IOException e) {
throw new RuntimeException("Exception occured while reading file " + path);
}
return line == null;
}
private void readLine() throws IOException {
if (!newLineRead) {
line = reader.readLine();
newLineRead = true;
}
}
}