Github user justinleet commented on a diff in the pull request:
https://github.com/apache/incubator-metron/pull/256#discussion_r79158991
--- Diff:
metron-platform/metron-common/src/main/java/org/apache/metron/common/hadoop/SequenceFileIterable.java
---
@@ -0,0 +1,138 @@
+/**
+ * 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.metron.common.hadoop;
+
+import com.google.common.collect.Iterators;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.BytesWritable;
+import org.apache.hadoop.io.LongWritable;
+import org.apache.hadoop.io.SequenceFile;
+import org.apache.log4j.Logger;
+
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.List;
+import java.util.NoSuchElementException;
+
+import static java.lang.String.format;
+
+public class SequenceFileIterable implements Iterable<byte[]> {
+ private static final Logger LOGGER =
Logger.getLogger(SequenceFileIterable.class);
+ private List<Path> files;
+ private Configuration config;
+
+ public SequenceFileIterable(List<Path> files, Configuration config) {
+ this.files = files;
+ this.config = config;
+ }
+
+ @Override
+ public Iterator<byte[]> iterator() {
+ return Iterators.concat(getIterators(files, config));
+ }
+
+ private Iterator<byte[]>[] getIterators(List<Path> files, Configuration
config) {
+ return files.stream().map(f -> new SequenceFileIterator(f,
config)).toArray(Iterator[]::new);
+ }
+
+ /**
+ * Cleans up all files read by this Iterable
+ *
+ * @return true if success, false if any files were not deleted
+ * @throws IOException
+ */
+ public boolean cleanup() throws IOException {
+ FileSystem fileSystem = FileSystem.get(config);
+ boolean success = true;
+ for (Path file : files) {
+ success &= fileSystem.delete(file, false);
+ }
+ return success;
+ }
+
+ private static class SequenceFileIterator implements Iterator<byte[]> {
+ private Path path;
+ private Configuration config;
+ private SequenceFile.Reader reader;
+ private LongWritable key = new LongWritable();
+ private BytesWritable value = new BytesWritable();
+ private byte[] next;
+ private boolean finished = false;
+
+ public SequenceFileIterator(Path path, Configuration config) {
+ this.path = path;
+ this.config = config;
+ }
+
+ @Override
+ public boolean hasNext() {
+ if (!finished && null == reader) {
+ try {
+ reader = new SequenceFile.Reader(config,
SequenceFile.Reader.file(path));
+ LOGGER.debug("Writing file: " + path.toString());
+ } catch (IOException e) {
+ throw new RuntimeException("Failed to get reader", e);
+ }
+ } else {
+ LOGGER.debug(format("finished=%s, reader=%s, next=%s", finished,
reader, next));
+ }
+ try {
+ //ensure hasnext is idempotent
+ if (!finished) {
+ if (null == next && reader.next(key, value)) {
+ next = value.copyBytes();
+ } else if (null == next) {
+ close();
+ }
+ }
+ } catch (IOException e) {
+ close();
+ throw new RuntimeException("Failed to get next record", e);
+ }
+ return (null != next);
+ }
+
+ private void close() {
+ LOGGER.debug("Closing file: " + path.toString());
+ finished = true;
+ try {
+ if (reader != null) {
+ reader.close();
+ reader = null;
+ }
+ } catch (IOException e) {
+ // ah well, we tried...
--- End diff --
Can we log this Exception? I'm not sure we can do anything about it, but
it would be nice to be able to ensure we can see it.
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