org.apache.hadoop.mapreduce.lib.join.CompositeInputSplit Maven / Gradle / Ivy
/**
* 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.hadoop.mapreduce.lib.join;
import java.io.DataInput;
import java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.HashSet;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableUtils;
import org.apache.hadoop.io.serializer.*;
import org.apache.hadoop.mapreduce.InputSplit;
import org.apache.hadoop.util.ReflectionUtils;
/**
* This InputSplit contains a set of child InputSplits. Any InputSplit inserted
* into this collection must have a public default constructor.
*/
@InterfaceAudience.Public
@InterfaceStability.Stable
public class CompositeInputSplit extends InputSplit implements Writable {
private int fill = 0;
private long totsize = 0L;
private InputSplit[] splits;
private Configuration conf = new Configuration();
public CompositeInputSplit() { }
public CompositeInputSplit(int capacity) {
splits = new InputSplit[capacity];
}
/**
* Add an InputSplit to this collection.
* @throws IOException If capacity was not specified during construction
* or if capacity has been reached.
*/
public void add(InputSplit s) throws IOException, InterruptedException {
if (null == splits) {
throw new IOException("Uninitialized InputSplit");
}
if (fill == splits.length) {
throw new IOException("Too many splits");
}
splits[fill++] = s;
totsize += s.getLength();
}
/**
* Get ith child InputSplit.
*/
public InputSplit get(int i) {
return splits[i];
}
/**
* Return the aggregate length of all child InputSplits currently added.
*/
public long getLength() throws IOException {
return totsize;
}
/**
* Get the length of ith child InputSplit.
*/
public long getLength(int i) throws IOException, InterruptedException {
return splits[i].getLength();
}
/**
* Collect a set of hosts from all child InputSplits.
*/
public String[] getLocations() throws IOException, InterruptedException {
HashSet hosts = new HashSet();
for (InputSplit s : splits) {
String[] hints = s.getLocations();
if (hints != null && hints.length > 0) {
for (String host : hints) {
hosts.add(host);
}
}
}
return hosts.toArray(new String[hosts.size()]);
}
/**
* getLocations from ith InputSplit.
*/
public String[] getLocation(int i) throws IOException, InterruptedException {
return splits[i].getLocations();
}
/**
* Write splits in the following format.
* {@code
* ......
* }
*/
@SuppressWarnings("unchecked")
public void write(DataOutput out) throws IOException {
WritableUtils.writeVInt(out, splits.length);
for (InputSplit s : splits) {
Text.writeString(out, s.getClass().getName());
}
for (InputSplit s : splits) {
SerializationFactory factory = new SerializationFactory(conf);
Serializer serializer =
factory.getSerializer(s.getClass());
serializer.open((DataOutputStream)out);
serializer.serialize(s);
}
}
/**
* {@inheritDoc}
* @throws IOException If the child InputSplit cannot be read, typically
* for failing access checks.
*/
@SuppressWarnings("unchecked") // Generic array assignment
public void readFields(DataInput in) throws IOException {
int card = WritableUtils.readVInt(in);
if (splits == null || splits.length != card) {
splits = new InputSplit[card];
}
Class[] cls = new Class[card];
try {
for (int i = 0; i < card; ++i) {
cls[i] =
Class.forName(Text.readString(in)).asSubclass(InputSplit.class);
}
for (int i = 0; i < card; ++i) {
splits[i] = ReflectionUtils.newInstance(cls[i], null);
SerializationFactory factory = new SerializationFactory(conf);
Deserializer deserializer = factory.getDeserializer(cls[i]);
deserializer.open((DataInputStream)in);
splits[i] = (InputSplit)deserializer.deserialize(splits[i]);
}
} catch (ClassNotFoundException e) {
throw new IOException("Failed split init", e);
}
}
}